| 1. |
- Kjellberg, Malin, 1974, et al.
(author)
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Challenges in implementing PBL: Chalmers Formula Student as a case
- 2015
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In: Proceedings of the 43rd Annual SEFI Conference June 29-July 2, 2015 Orléans, France. - 9782873520120
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Conference paper (peer-reviewed)abstract
- Over the past two decades, we have witnessed several worldwide calls for reform in engineering education. Despite these calls there is still a significant gap between educational research and practice [1]. Previous research has demonstrated that faculty are aware of student-centred teaching methods, believe in them and try them out, but find it difficult to deal with unexpected issues that arise and thus often return to more traditional teaching methods [2]. It is therefore important to identify, describe and deal with different types of challenges or barriers that have a direct bearing on educational development.In this paper, we use a case-study approach to identify and describe key challenges in relation to implementing project- and problem-based learning (PBL) in engineering education. Based on the first author’s experiences of running and developing the PBL course Chalmers Formula Student over six years, we give a thick description of challenges in connection to running a large multi-disciplinary Design-Build-Test, DBT, project. We also describe how these challenges have been addressed over the years. As a theoretical lens for identifying and describing these challenges, we draw on an extended constructive alignment framework [3].The challenges we identified do not only concern student learning or course design, but also the organisation of the course within the university and of the teacher team, different levels of communication: multicultural and cross-disciplinary within the teams, as well as external communication between the teacher team and the university, industry and society. Further challenges comprise the recruitment and composition of teams consisting of students with different skills as well as providing possibilities for the student teams to develop ownership of the project. It is also a challenge to run an industrial project and course in parallel, manifested here in the “two-hats” issue for the person acting as examiner and project manager.Some of these challenges we identified in a workshop discussing challenges with PBL courses, held by the authors at the international CDIO conference 2014 and attended by a broad spectre of teachers. The challenges discussed mainly concern course design, organisation, activities and especially assessment, which are the obvious and most important challenges when first implementing PBL methods. After some time managing a PBL course, this is especially true for large DBT projects, the full scope of challenges will unveil.These different challenges highlight the complexity of implementing PBL courses in engineering education and point to the importance of providing faculty with adequate support.
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| 2. |
- Antona, Jacobo, 1981, et al.
(author)
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Correlation of Global Head and Brain Tissue Injury Criteria to Experimental Concussion derived from Monkey Head Trauma Experiments
- 2013
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In: IRCOBI Conference. - 2235-3151. ; :IRC-13-55, s. 509-522
-
Conference paper (peer-reviewed)abstract
- A series of 24 frontal head traumatic impacts on macaques carried out in the past were simulatedwith a validated finite element model of the specimens. From these simulations, brain tissue response and headaccelerations were extracted. Based on the accelerations, global head injury criteria were calculated.Correlation between the brain tissue mechanical parameters, the global head injury criteria and the concussionscored in the experiments were analyzed. Based on this analysis, global head injury criteria that best correlatewith concussion score for frontal impacts were identified and injury risk functions for brain tissue that can beused for human FE models are proposed. In addition, the new results were compared to a previous study basedon simulations of 19 occipital head impacts from the same data source.
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| 3. |
- Arbogast, Kristy B, et al.
(author)
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Child Occupant Protection: Latest Knowledge and Future Opportunities – Results of a 2015 Workshop in Gothenburg, Sweden
- 2015
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In: 13th International Conference on Protection of children in cars, December 3 – 4, Munich, Germany.
-
Conference paper (other academic/artistic)abstract
- Child occupant protection research remains a critical need for industry, academia, government and safety advocacy organizations. While reductions in fatalities and serious injuries have been achieved, motor vehicle crashes remain a leading cause of death and disability for children and adolescents and as a result, represent a public health priority.To facilitate international coordination and sharing of knowledge around this topic, the fourth biennial international workshop on Child Occupant Protection was convened in September 2015, bringing together worldwide leaders in the fields of child occupant protection, biomechanics, and auto safety to critically review the state-of-knowledge in the field and identify high-priority research topics and strategize toward their implementation.Summaries of previous workshops were presented at the 2011 and 2013 Protection of Children in Cars Conferences. The following describes the recommendations that emanated from the 2015 meeting.
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| 4. |
- Brindefalk, B., et al.
(author)
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Bacterial composition in Swedish raw drinking water reveals three major interacting ubiquitous metacommunities
- 2022
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In: Microbiologyopen. - : Wiley. - 2045-8827. ; 11:5
-
Journal article (peer-reviewed)abstract
- Background Surface raw water used as a source for drinking water production is a critical resource, sensitive to contamination. We conducted a study on Swedish raw water sources, aiming to identify mutually co-occurring metacommunities of bacteria, and environmental factors driving such patterns. Methods The water sources were different regarding nutrient composition, water quality, and climate characteristics, and displayed various degrees of anthropogenic impact. Water inlet samples were collected at six drinking water treatment plants over 3 years, totaling 230 samples. The bacterial communities of DNA sequenced samples (n = 175), obtained by 16S metabarcoding, were analyzed using a joint model for taxa abundance. Results Two major groups of well-defined metacommunities of microorganisms were identified, in addition to a third, less distinct, and taxonomically more diverse group. These three metacommunities showed various associations to the measured environmental data. Predictions for the well-defined metacommunities revealed differing sets of favored metabolic pathways and life strategies. In one community, taxa with methanogenic metabolism were common, while a second community was dominated by taxa with carbohydrate and lipid-focused metabolism. Conclusion The identification of ubiquitous persistent co-occurring bacterial metacommunities in freshwater habitats could potentially facilitate microbial source tracking analysis of contamination issues in freshwater sources.
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| 5. |
- Brolin, Karin, 1974, et al.
(author)
-
A prestudy of the potential of using finite element analysis for understanding horse accidents
- 2015
-
Reports (other academic/artistic)abstract
- This prestudy is an investigation into the potential of using the THUMS [5] model and LS-Dyna [6] simulations to understand the risk of thorax injury in horse related accidents such as horse kicks, tramples, falls from horse backs or rotational falls. A simple model of a security vest was also developed for the THUMS model, to facilitate injury risk comparisons with and without the vest. The severity of thorax injuries was quantified by measuring local stresses and strains in the cortical bone of the ribs, as well as the total deformation of the thorax, measured with Dmax and DcTHOR [2]. This prestudy attempt to answer five questions:•What is the worst location on the chest to be trampled by a horse with respect to rib fractures?•How does the stiffness of the ground compound affect the risk of rib fractures when trampled by a horse?•How does the risk of thorax injuries vary when falling off a horseback in different angles?•How does the momentum of a horse kick affect the risk of thorax injury on the THUMS model with and without a protective vest?•How can a rotational fall be modelled and how severe is the injury outcome?Simulations were set up in LS-Dyna with the THUMS model representing the human body with different environments built up around it representing the scenarios in the five questions. The structure of the report follows the five questions through both the method and results sections.
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| 6. |
- Brolin, Karin, 1974, et al.
(author)
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Active Child Models for Traffic Safety Research Interim Report 2, October 2013
- 2014
-
Reports (other academic/artistic)abstract
- The project Active Child Models for Traffic Safety Research is funded by Folksams Forskningsstiftelse. The overall project aim is to increase the safety of child car occupants and thereby reduce the number of traffic induced injuries in 3 to 12 year-old children. The specific aim is to create a computer model of a child that includes active musculature. Based on literature review of child numerical models it was decided to proceed with child multi body models in the MADYMO code (TASS, Rijswijk, the Netherlands). The 6 and 10 year-old child facet models, the Q6, Q10 and Hybrid III 6 year-old ATD models were compared regarding kinematics to experimental data with child volunteers in 1 g braking and steering events. The ATD models did not represent the experimental ATD response. The child facet models represented the child volunteers for about 3-400 ms of the events, and after that behaved cadaver like with much larger head and sternum displacement compared to the volunteers. Then, the child facet model representing the 6 year-old child was chosen to implement muscle activity. Muscle activity was represented by an active spine that applied torques at each vertebral joint in response to joint angle changes in two directions: flexion-extension motions and lateral bending. A partial, integrative and derivative controller governed with input from angular sensors controlled torque actuators. The controller gains were based on adult data and scaled by 50% for a first version of the active child model. Then, an optimization approach was adopted to tune the control gains in the lumbar, thoracic and cervical spine such that head and sternum kinematics would correlate to the mean values from the volunteer braking and steering experiments. The first version of the active child model had a significantly improved biofidelity compared to the original facet model, with shape and magnitude of head and sternum displacements similar to the volunteer data. The optimization created non biofidelic gain combinations, although providing important input to future work. It is necessary to perform a reanalyses of the experimental data in order to have data for powerful performance criteria in future optimizations. Future work is needed to improve the optimization and provide controller gains based on child volunteer data, rather than scaled adult data. Then, the tuned active child model has to be validated to new experimental data sets. A new steering and braking experiment with approximately 1 g acceleration loading was performed during 2013 and will provide a good validation data set. Also, there is a data set with child volunteers in sled test of approximately 4 g that can be used. Then, the active model is suitable to perform parameters studies of how child restraints design, emergency manoeuver characteristics and child posture influences the safety of children in the rear seat.
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| 7. |
- Brolin, Karin, 1974, et al.
(author)
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Active Spine Modeling Representing a 6 Year-Old Child
- 2014
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In: 7th World Congress of Biomechanics.
-
Conference paper (other academic/artistic)abstract
- In a car crash, properly restrained forward facing children may sustain head injuries due to contact with the car interior. Emergency events such as braking and steering will influence the kinematics of the child, thereby affecting the child’s interaction with the restraint systems. Volunteer experiments (Stockman et al. 2013) have shown that children around six years of age, properly restrained on a booster cushion, may slip out of the shoulder belt during a 1g emergency event, while older children can maintain their posture better. A numerical human body model of the 6 year-old would be a valuable tool to study and improve the performance of restraint systems in the pre-crash phase. Compared to a crash, an emergency event typically has low g and long duration loading; hence, the muscle activity will influence the kinematics of the child. Therefore, the aim of this work is to develop an active 6 year-old human body model.The 6 year-old facet occupant multi body model in the MADYMO code (TASS, Rijswijk, the Netherlands) was selected. The spine is composed of rigid vertebral bodies connected with spherical joints. Muscle activity was implemented by applying torques at each vertebral joint for flexion-extension and lateral bending. The torque actuators were controlled by proportional, integrative and derivative controllers comparing the current joint angles to an initial posture reference value. The controller gains were based on adult data and scaled by 50% for a first version of the active child model. The resulting active 6 year-old model was used to simulate the volunteer experiments by Stockman et al. 2013. The model was seated on a booster cushion and loaded with the average experimental pulse. The first version of the active child model had a significantly improved biofidelity compared to the original facet model, with shape and magnitude of displacements similar to the volunteer data, see Figure.It is concluded that the first version active 6 year-old model can reproduce this specific emergency event. Future work should focus on controller gain optimization and further validation.
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| 8. |
- Brolin, Karin, 1974, et al.
(author)
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Aiming for an average female virtual human body model for seat performance assessment in rear-end impacts
- 2015
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In: The 24th ESV Conference Proceedings.
-
Conference paper (peer-reviewed)abstract
- The female part of the population suffers more Whiplash Associated Disorders (WAD) in car crashes than males. Several studies have illustrated the need to consider the female population when developing and assessing the WAD prevention performance of advanced restraint systems in rear-end collisions. Presently only one crash test dummy is available, the average sized male BioRID. Recently a virtual dummy model of an average female, EvaRID, was developed and used in rear impact simulations. The results stressed the need for models representing the female part of the population, as well. Virtual crash simulations have become essential in traffic safety and with models of both an average male and female, further steps in addressing improved assessment of WAD prevention can be taken. The present paper presents a starting point of research aiming to develop an open-source average female Finite Element (FE) model with an anatomically detailed cervical spine. This paper provides a review of the literature to identify gender specific neck biomechanics and anatomical differences, followed by a review of published FE models of the cervical spine. Data on vertebral body dimensions (height, width, depth, spinal canal diameter, facet joint angles) have been compiled from biomechanical literature. Significant gender differences exist for the vertebral body depth and width, the spinal curvature in the seated posture, and the spinal stiffness and range of motion. All have the potential to influence the outcome of an impact and should be accounted for in the development of WAD prevention. The review of FE models of the cervical spine presented 17 models based on male geometry but only one model scaled to represent a female. An overview of the models are given with respect to the solver, geometry source, number of elements, and implementation of the facet joints, ligaments, and muscles. It is recommended that an average female model is developed with focus on; 1) the shape of the female vertebral body, especially the depth and width that provides less support area than for males,2) defining the spinal curvature representative of seated female volunteers who generally display less lordosis than males, 3) the dimensions of the spinal ligaments, rather than the material properties, to capture the larger range of motion and less spinal stiffness of female subjects compared to males, and validation to female volunteers and PMHS tests for range of motion, while failure prediction seem less gender sensitive.
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| 9. |
- Brolin, Karin, 1974
(author)
-
Biomekanik och skadeprevention
- 2015
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In: Elitidrottskonferens.
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Conference paper (other academic/artistic)abstract
- Den grundläggande forskning inom biomekanik med fokus på människans skadetoleranser och skyddsprinciper inom trafiksäkerhet kan användas inom sport och idrott för att minimera skaderisker, med bibehållen eller ökad idrottsprestation.
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| 10. |
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| 11. |
- Brolin, Karin, 1974-
(author)
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Cervical Spine Injuries - Numerical Analyses and Statistical Survey
- 2002
-
Doctoral thesis (other academic/artistic)abstract
- Injuries to the neck, or cervical region, are very importantsince there is a potential risk of damage to the spinal cord.Any neck injury can have devastating if not life threateningconsequences. High-speed transportation as well as leisure-timeadventures have increased the number of serious neck injuriesand made us increasingly aware of its consequences.Surveillance systems and epidemiological studies are importantprerequisites in defining the scope of the problem. Thedevelopment of mechanical and clinical tools is important forprimary prevention of neck injuries.Thus, the main objectives of the present doctoral thesisare:- To illustrate the dimension of cervical injuries inSweden,- To develop a Finite Element (FE) model of the uppercervical spine, and- To study spinal stability for cervical injuries.The incidence studies were undertaken with data from theinjury surveillance program at the Swedish National Board ofHealth and Welfare. All in-patient data from Swedish hospitals,ranging over thirteen years from 1987 to 1999, were analyzed.During this period 14,310 nonfatal and 782 fatal cervicalinjuries occurred. The lower cervical spine is the mostfrequent location for spinal trauma, although, this changeswith age so that the upper cervical spine is the most frequentlocation for the population over 65 years of age. The incidencefor cervical fractures for the Swedish population decreased forall age groups, except for those older than 65 years of age.The male population, in all age groups, has a higher incidencefor neck fractures than females. Transportation relatedcervical fractures have dropped since 1991, leaving fallaccidents as the sole largest cause of cervical trauma.An anatomically detailed FE model of the human uppercervical spine was developed. The model was validated to ensurerealistic motions of the joints, with significant correlationfor flexion, extension, lateral bending, axial rotation, andtension. It was shown that an FE-model could simulate thecomplex anatomy and mechanism of the upper cervical spine withgood correlation to experimental data. Three studies wereconducted with the FE model. Firstly, the model of the uppercervical spine was combined with an FE model of the lowercervical spine and a head model. The complete model was used toinvestigate a new car roof structure. Secondly, the FE modelwas used for a parameter study of the ligament materialcharacteristics. The kinematics of the upper cervical spine iscontrolled by the ligamentous structures. The ligaments have tomaintain spinal stability while enabling for large rotations ofthe joints. Thirdly, the FE-model was used to study spinalinjuries and their effect on cervical spinal stability inflexion, extension, and lateral bending. To do this, the intactupper cervical spine FE model was modified to implementruptures of the various spinal ligaments. Transection of theposterior atlantooccipital membrane, the ligametum flavum andthe capsular ligament had the most impact on flexion, while theanterior longitudinal ligament and the apical ligamentinfluenced extension.It is concluded that neck injuries in Sweden is a problemthat needs to be address with new preventive strategies. It isespecially important that results from the research on fallaccidents among the elderly are implemented in preventiveprograms. Secondly, it is concluded that an FE model of thecervical region is a powerful tool for development andevaluation of preventive systems. Such models will be importantin defining preventive strategies for the future. Lastly, it isconcluded that the FE model of the cervical spine can increasethe biomechanical understanding of the spine and contribute inanalyses of spinal stability.
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| 12. |
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| 13. |
- Brolin, Karin, 1974, et al.
(author)
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Development of an Active 6-Year-Old Child Human Body Model for Simulation of Emergency Events
- 2015
-
In: 2015 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury. ; :IRC-15-74, s. 689-700
-
Conference paper (peer-reviewed)abstract
- One contributing factor to head injury in restrained child occupants is pre‐crash maneuvers andactive child human body models (HBMs) can be useful tools to design pre‐crash interventions with child safety infocus. This paper implemented postural control in the MADYMO human facet occupant model of a 6‐year‐oldchild using feedback controlled torque actuators. Control parameters were tuned and the active HBM wascompared to experimental data from braking and steering events with child volunteers. The head and sternumdisplacements of the active HBM were within one standard deviation of the experimental data, while theoriginal HBM did not capture the volunteer kinematics at all. By predicting biofidelic child kinematics, thedeveloped model shows potential as a useful tool for the automotive industry to study the protective propertiesof restraint systems in pre‐crash scenarios. For autonomous steering events, it was illustrated that the shape ofthe acceleration pulse highly influences the peak head displacements of child occupants. This is an aspect thatneeds to be considered when autonomous interventions are designed, to ensure the safety of short forwardfacing child occupants.
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| 14. |
- Brolin, Karin, 1974, et al.
(author)
-
Evaluation at low g-level loading
- 2014
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In: 5th International Symposium on Human Modelling and Simulation in Automotive Engineering, Munich, Germany, October 16-17, 2014.
-
Conference paper (other academic/artistic)
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| 15. |
- Brolin, Karin, 1974, et al.
(author)
-
Explicit finite element methods for equestrian applications
- 2016
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In: Procedia Engineering. - : Elsevier BV. - 1877-7058 .- 1877-7058. ; 147, s. 275-280
-
Conference paper (peer-reviewed)abstract
- A virtual human body model (HBM), developed for vehicle crash simulations, was used to conduct a pilot study of dangerous accidents that occur in equestrian sports. It was performed to illustrate the potential that the explicit finite element (FE) HBMs have to improve rider safety and to assess the protective capacity of the safety vest. Four different questions were addressed: 1. When a rider is trampled by a horse, how does the risk of injury vary with chest impact location? 2. Does a safety-vest provide protection if the rider is kicked by a horse and does the protection vary with the violence of the hoof impact? 3. Can a safety-vest provide any benefit when the rider is hit by the horse after a rotational fall? 4. How does the risk for thoracic injuries vary when the rider falls off the back of a horse at different angles? The HBM was the Total Human Model for Safety AM50 version 3.0 (Toyota Motor Corporation, Japan), improved for thorax injury predictability in a previous automotive project. The FE code was LS-DYNA (Livermore Software Technology Corporation, USA). Models of a generic safety vest, a horse impactor and a hoof were developed as part of this project. The risk of thorax injury was evaluated with stresses and strains measured for each rib, and the chest deformation criteria Dmax and DcTHOR. 1. The risk of injury was higher for hoof impacts close to the sternum compared to more lateral locations that had up to 25% less risk. Hence, this knowledge could be used to optimize novel safety-vest designs with HBM simulations. 2. Yes, the safety-vest provided protection against horse kicks, and it varied with the violence of the kick. Therefore, if the range of impact energy that occurs in real-world accidents is known, HBM simulations can be used to optimize the vest material properties. 3. No, the safety-vest did not provide any benefit when the horse lands on top of the rider. This conclusion suggests that safety measures should focus on preventing this type of accident, rather than designing personal protection for the rider. 4. When the rider falls with the head first, the number of predicted rib fractures increases compared to flat falls. However, the model predicts rib fractures for all of the falls simulated from a height of 1.5 meters for a rider without a safety vest. To conclude, FE HBMs have the potential to improve equestrian safety and further studies on equestrian safety-vests designs are warranted. (C) 2016 The Authors. Published by Elsevier Ltd.
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| 16. |
- Brolin, Karin, 1974, et al.
(author)
-
Finite Element Musculoskeletal Model with Feedback Control to Simulate Spinal Postural Responses
- 2014
-
In: 7th World Congress of Biomechanics. ; July 6-11, Boston, USA:18-14
-
Conference paper (other academic/artistic)abstract
- Today, most Finite Element (FE) Human Body Models (HBMs) are intended for crash simulations and not for pre-crash events, due to the lack of active muscles. To study combined pre- and in crash events, muscle activity is essential. Therefore, this work presents a method to implement postural muscle responses in an FE HBM.The Total HUman Model for Safety (THUMS®) AM50 version 3.0 (Toyota Central Labs Inc, Nagakute, Japan) was chosen and a model of active musculature was added (Östh et al. 2012). The trunk, neck, upper and lower extremities were represented by 394 Hill-type line elements. Muscle activation levels were generated by seven proportional, integrative, and derivative feedback controllers for the controlled angles of the spine and upper extremities, Figure 1. For each controller, the deviation from the initial angle was used to generate correcting moment requests to the flexors and extensor muscles in the respective body region. Neural delay was implemented by a time offset for the controlled angle. The request was scaled with the maximum strength of the muscles and then passed through a muscle activation dynamics model.The model response was compared to an experimental volunteer study that measured muscle activity, kinematics, and boundary conditions for drivers and passengers, riding on rural roads in a passenger car, subjected to autonomous and driver braking. The experimental braking pulse was applied to the model seated in an FE model of the front seat and restrained with seat belts. The results show that postural feedback control can be utilized to model driver and passenger responses to autonomous braking interventions in the sagittal plane. However, the model overestimated head rotation for driver braking events. Volunteer muscle activity occurred prior to deceleration onset, which cannot be captured by the feedback control model. Therefore, a hypothesized anticipatory postural response was implemented by modifying the reference value of the feedback controllers based on the volunteer data. The result was earlier onset of muscle activity and a kinematic response that was within one standard deviation of the corresponding test data from volunteers performing maximum braking.
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| 17. |
- Brolin, Karin, 1974, et al.
(author)
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HUMAN BODY MODELING FOR APPLIED TRAFFIC SAFETY
- 2011
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In: SVENSKA MEKANIKDAGAR, 13-15 JUNI, 2011, Göteborg.
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Conference paper (other academic/artistic)abstract
- Traffic injuries are an important public health issue. To prevent, diagnose and treat injuriesit is vital to understand the mechanics of injuries. Here, mathematical models of the humanpresent a valuable complement to other models, such as animal models and crash dummies.Today, Human Body Models (HBM) are recognized as important tools within traffic safetyresearch. To successfully apply an HBM to improve and evaluate real life safety systems,it has to: (1) be numerically robust in a wide range of crash loading conditions, (2) becomputationally efficient to enable analyses with full car models, (3) represent the humanpopulation with respect to age, gender and anthropometry, (4) maintain its posture in agravitational field for pre-crash events, (5) predict the onset of tissue injury and organ failure,and (6) simulate muscle tension due to bracing and muscle reflexes. Therefore, work is ongoingto model the active muscle response and improve the injury predictability of currently availableFE HBM.The commercially available HBM Total HUman Model for Safety [1], called THUMS,was used with the explicit capabilities in the FE code LS-DYNA [2]. It is a model of a 50thpercentile adult male vehicle occupant and contains approximately 150,000 elements. To studythoracic injuries, the responses of the THUMS were compared to several cadaver experiments.Then, a sensitivity study was performed to evaluate the influence of belt interaction and tissueparameters on the predicted thoracic response. Lastly, several candidates to predict rib cagefractures were compared in loading conditions relevant to frontal car crashes.The central nervous system controls the muscle contraction and was modeled using feedbackproportional, integral, and derivative (PID) control. The reference signal is a joint angledefining a body position. The neural delays, due to the time needed for the nerve signalsto travel back and forth to the central nervous system, and muscle activation dynamics areincluded. Firstly, this was applied to evaluate the response of the elbow joint comparedto volunteer experiments [3], and secondly, to compare passenger kinematics in autonomousbraking events. It was seen that by changing the controller gains, the model can can capturedifferences in the muscle response when the human is relaxed compared to tensed, which isimportant to study the difference between occupants who are or who are not aware of anoncoming accident.
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| 18. |
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| 19. |
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| 20. |
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| 21. |
- Brolin, Karin, 1974
(author)
-
Human Body Models
- 2016
-
In: Transport Planning and Traffic Safety - Making Cities, Roads, and Vehicles Safer. - 9781498751452 - 9781498751476 ; , s. 175-186
-
Book chapter (other academic/artistic)abstract
- Experimental studies with human subjects, volunteers or post mortem human subjects (PMHS)help us understand the biomechanics of the impact during a traffic crash. Anthropometric crash test dummies (ATDs) were developed to provide tools for the development and assessment of safety systems to address the variation in human anthropometry. ATDs are available with varying specifications of gender, age, and body sizes. Still, due to persistant limitations associated with ATDs and the advancement in computer based simulation capabilities, the human body computer models have become more popular in recent times. Their ability to simulate both precrash and post-crash scenarios, including active muscle response, has made them invaluable to crash analysis. This chapter discusses basic methodological considerations regarding human body models, includes a limited review of recently published whole body models, and briefly presents the biomechanical properties of human tissue. The chapter concludes with a discussion on futureoutlook and recommendations for targeted research on the aspect of injury predictability and making human body models more numerically robust.
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| 22. |
- Brolin, Karin, 1974, et al.
(author)
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Safety of children in cars: A review of biomechanical aspects and human body models
- 2015
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In: IATSS Research. - : Elsevier BV. - 0386-1112. ; 38:2, s. 92-102
-
Research review (peer-reviewed)abstract
- The protection of children in motor vehicle crashes has improved since the introduction of child restraint systems. However, motor vehicle crashes remain one of the top leading causes of death for children. Today, computer-aided engineering is an essential part of vehicle development and it is anticipated that safety assessments will increasingly rely on simulations. Therefore, this study presents a review of important biomechanical aspects for the safety of children in cars, including child human body models, for scenarios ranging from on-road driving, emergency maneuvers, and pre-crash events to crash loading. The review is divided into four parts: Crash safety, On-road driving for forward facing children, Numerical whole body models, and Discussion and future outlook.The first two parts provide ample references and a state-of-the-art description of important biomechanical aspects for the safety of children in cars. That children are not small adults has been known for decades and has been considered during the development of current restraints that protect the child in the crash phase. The head, neck, thorax, and pelvis are body areas where development with age changes the biomechanics and the interaction with restraint systems. The rear facing child seat distributes the crash load over a large area of the body and has proved to be a very efficient means of reducing child injuries and fatalities. Children up to age 4. years need to be seated rearward facing for optimal protection, mainly because of the proportionally large head, neck anthropometry and cartilaginous pelvis. Children aged 4 up to 12. years should use a belt positioning booster together with the vehicle seat belt to ensure good protection, as the pelvis is not fully developed and because of the smaller size of these children compared to adults. On-road driving studies have illustrated that children frequently change seated posture and may choose slouched positions that are poor for lap belt interaction if seated directly on the rear seat. Emergency maneuvers with volunteers illustrate that pre-crash loading forces forward-facing children into involuntary postures with large head displacements, having potential influence on the risk of head impact. Children, similar to adults, benefit from the safety systems offered in the vehicle. By providing child adaptability of the vehicle, such as integrated booster cushions, the child-restraint interaction can be further optimized. An example of this is the significant reduction of lap belt misuse when using integrated boosters, due to the simplified and natural positioning of the lap belt in close contact with the pelvis. The research presented in this review illustrates that there is a need for enhanced tools, such as child human body models, to take into account the requirements of children of different ages and sizes in the development of countermeasures.To study how children interact with restraints during on-road driving and during pre- and in-crash events, numerical child models implementing age-specific anthropometric features will be essential. The review of human whole body models covers multi body models (age 1.5 to 15. years) and finite element models (ages 3, 6, and 10. years). All reviewed child models are developed for crash scenarios. The only finite element models to implement age dependent anthropometry details for the spine and pelvis were a 3. year-old model and an upcoming 10. year-old model. One ongoing project is implementing active muscles response in a 6. year-old multi body model to study pre-crash scenarios. These active models are suitable for the next important step in providing the automotive industry with adequate tools for development and assessment of future restraint systems in the full sequence of events from pre- to in-crash.
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| 23. |
- Brolin, Karin, 1974, et al.
(author)
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Towards omni-directional active human body models
- 2016
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In: 6th International Symposium on Human Modeling and Simulation in Automotive Engineering, Heidelberg, GERMANY, October 20-21.
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Conference paper (other academic/artistic)
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| 24. |
- Cutcliffe, Hattie, et al.
(author)
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Gender Differences in Occupant Posture and Muscle Activity with Motorized Seat Belts
- 2015
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In: The 24th ESV Conference Proceedings.
-
Conference paper (other academic/artistic)abstract
- The aim of this study was to assess gender differences in the posture and muscular activity of occupants in response to pretension from motorized seatbelts. Male and female vehicle occupants were tested in both front seat positions during normal driving and autonomous braking. This data is useful for the development of human body models (HBM), and increases the understanding of the effects of motorized belts.Kinematics and electromyography (EMG) were analyzed for 18 volunteers (9 male, 9 female) subjected to autonomous braking (11 m/s2 deceleration) during real driving on rural roads. Two restraint configurations were tested: a standard belt and a motorized belt, activated 240 ms before the initiation of braking. Statistical comparison of volunteers’ posture and normalized EMG amplitudes was performed to understand differences incurred by the motorized belts, as well as to compare response across gender and role (occupant position within the vehicle). Data was analyzed both prior to and at vehicle deceleration, which occurred 240 ms after motorized belt onset.Motorized belts significantly affected all postural metrics, and significantly elevated the activity of all muscles compared to typical riding. Though increases in muscle activity were small at deceleration onset compared with typical riding for male occupants and female passengers, female drivers demonstrated significantly larger increases in muscular activity: between 5 and 13% of the maximum voluntary contraction (MVC). At deceleration onset, standard belts showed little change in posture or muscle activation, with the median changes being well within the ranges exhibited during typical riding for all groups (i.e. not distinguishable from typical riding). Typical riding postures of males and females were similar, as were muscular activation levels—generally less than 5% of the MVC. However, drivers exhibited significantly higher muscular activity in the arm and shoulder muscles than passengers.Limitations include the repeated nature of the testing, as prior work has shown that habituation across trials alters occupant response compared to that of unaware occupants. However, randomization of the trial order helped mitigate potential habituation effects. Another limitation is the sample size of 18 volunteers.An important finding of this study is that the increase in occupant muscular activation seen with motorized belts was gender-specific: at deceleration, the change in activation of most muscles was significantly different across gender and belt type, with female drivers exhibiting larger increases in muscular activation than male drivers or passengers of either gender, particularly in the arm muscles. These activations appeared to be startle responses, and may have implications for interactions with the steering wheel and motion during a braking or crash event. This warrants further studies and stresses the importance of quantifying male and female subjects separately in future studies of pre-crash systems.
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| 25. |
- Cutcliffe, Hattie, et al.
(author)
-
Gender differences in Occupant Posture during Driving and Riding
- 2017
-
In: Conference proceedings International Research Council on the Biomechanics of Injury, IRCOBI. - 2235-3151. ; Antwerp, 2017, September 13-15:IRC-17-12, s. 23-33
-
Conference paper (peer-reviewed)abstract
- The aim of this study was to compare postures of male and female vehicle occupants, tested in both front seat positions, during normal driving and deceleration onset. These data are useful for the development and initialisation of computational human body models. A secondary aim was to examine the effect of reversible, motorised seat belts in these events. Kinematics were analysed for volunteers driving on rural roads, prior to autonomous braking (11 m/s2 deceleration). Two restraint configurations were tested: a standard versus a motorized belt, activated 200 ms before braking initiation. Kinematic metric comparison via ANCOVA was performed to understand postural differences across gender, role (driver/passenger), and belt type (standard/motorised). Data was analysed prior to and at vehicle deceleration, termed typical riding and initial braking, respectively.While males and females displayed similar postures during typical riding, differences existed between driversand passengers, especially with respect to neck posture. Drivers displayed more protracted neck postures, withsignificantly smaller (by 22‐27 mm, depending on gender) head‐to‐sternum horizontal distances, than passengers.Motorised belts significantly changed posture during initial braking, notably of the chest (which was shiftedposteriorly by approximately 13 mm, depending on gender and role), while standard belts did not. Within a given belt type, occupants’ change in posture was similar across gender and role during initial braking.
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| 26. |
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| 27. |
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| 28. |
- Fice, Jason, 1985, et al.
(author)
-
Neck Muscle and Head/Neck Kinematic Responses While Bracing Against the Steering Wheel During Front and Rear Impacts
- 2021
-
In: Annals of Biomedical Engineering. - : Springer Science and Business Media LLC. - 1573-9686 .- 0090-6964. ; 49:3, s. 1069-1082
-
Journal article (peer-reviewed)abstract
- Drivers often react to an impending collision by bracing against the steering wheel. The goal of the present study was to quantify the effect of bracing on neck muscle activity and head/torso kinematics during low-speed front and rear impacts. Eleven seated subjects (3F, 8 M) experienced multiple sled impacts (Delta v = 0.77 m/s; a(peak) = 19.9 m/s(2), Delta t = 65.5 ms) with their hands on the steering wheel in two conditions: relaxed and braced against the steering wheel. Electromyographic activity in eight neck muscles (sternohyoid, sternocleidomastoid, splenius capitis, semispinalis capitis, semispinalis cervicis, multifidus, levator scapulae, and trapezius) was recorded unilaterally with indwelling electrodes and normalized by maximum voluntary contraction (MVC) levels. Head and torso kinematics (linear acceleration, angular velocity, angular rotation, and retraction) were measured with sensors and motion tracking. Muscle and kinematic variables were compared between the relaxed and braced conditions using linear mixed models. We found that pre-impact bracing generated only small increases in the pre-impact muscle activity (< 5% MVC) when compared to the relaxed condition. Pre-impact bracing did not increase peak neck muscle responses during the impacts; instead it reduced peak trapezius and multifidus muscle activity by about half during front impacts. Bracing led to widespread changes in the peak amplitude and timing of the torso and head kinematics that were not consistent with a simple stiffening of the head/neck/torso system. Instead pre-impact bracing served to couple the torso more rigidly to the seat while not necessarily coupling the head more rigidly to the torso.
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| 29. |
- Ghaffari, Ghazaleh, 1985, et al.
(author)
-
Passenger muscle responses in lane change and lane change with braking maneuvers using two belt configurations: Standard and reversible pre-pretensioner
- 2019
-
In: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 20:sup1, s. S43-S51
-
Journal article (peer-reviewed)abstract
- Objective : The introduction of integrated safety technologies in new car models calls for an improved understanding of the human occupant response in precrash situations. The aim of this article is to extensively study occupant muscle activation in vehicle maneuvers potentially occurring in precrash situations with different seat belt configurations. Methods : Front seat male passengers wearing a 3-point seat belt with either standard or pre-pretensioning functionality were exposed to multiple autonomously carried out lane change and lane change with braking maneuvers while traveling at 73 km/h. This article focuses on muscle activation data (surface electromyography [EMG] normalized using maximum voluntary contraction [MVC] data) obtained from 38 muscles in the neck, upper extremities, the torso, and lower extremities. The raw EMG data were filtered, rectified, and smoothed. All muscle activations were presented in corridors of mean ± one standard deviation. Separate Wilcoxon signed ranks tests were performed on volunteers’ muscle activation onset and amplitude considering 2 paired samples with the belt configuration as an independent factor. Results : In normal driving conditions prior to any of the evasive maneuvers, activity levels were low (<2% MVC) in all muscles except for the lumbar extensors (3–5.5% MVC). During the lane change maneuver, selective muscles were activated and these activations restricted the sideway motions due to inertial loading. Averaged muscle activity, predominantly in the neck, lumbar extensor, and abdominal muscles, increased up to 24% MVC soon after the vehicle accelerated in lateral direction for all volunteers. Differences in activation time and amplitude between muscles in the right and left sides of the body were observed relative to the vehicle’s lateral motion. For specific muscles, lane changes with the pre-pretensioner belt were associated with earlier muscle activation onsets and significantly smaller activation amplitudes than for the standard belt (P <.05). Conclusions : Applying a pre-pretensioner belt affected muscle activations; that is, amplitude and onset time. The present muscle activation data complement the results in a preceding publication, the volunteers’ kinematics and the boundary conditions from the same data set. An effect of belt configuration was also seen on previously published volunteers’ kinematics with lower lateral and forward displacements for head and upper torso using the pre-pretensioner belt versus the standard belt. The data provided in this article can be used for validation and further improvement of active human body models with active musculature in both sagittal and lateral loading scenarios intended for simulation of some evasive maneuvers that potentially occur prior to a crash.
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| 30. |
- Gonzalez Carcedo, Marta, 1986, et al.
(author)
-
Generation of numerical human models based on medical imaging
- 2012
-
Reports (other academic/artistic)abstract
- The aim of this project was to increase the knowledge of how numerical models can be generated based on medical imaging data. The software used was Scan IP+FE/+CAD (Simpleware Ltd, UK). Three studies were conducted to generate models for Computer Fluid Dynamics (CFD) and Finite Element (FE) analysis, focusing on the medical imaging process. The real geometry of an aorta with a stent graft was generated based on Computer Tomography (CT) images from two patients. Several meshes were generated, evaluated and exported to OpenFOAM for CFD analysis. It was possible to run the simulation. Two FE models of the cervical vertebrae were generated based on CT images of female necks. The mesh density needed to capture joint slope and other important features were investigated. Lastly, image processing of rat and monkey head, brain and neck was performed to extract anatomical details and compare brain size with specimen mass.This project was finalized with a workshop to spread the gained knowledge to the graduate students and researchers at the Department of Applied Mechanics of Chalmers, active in the field of human body modeling, and open to participants from partners of the SAFER - Vehicle and Traffic Safety Center- at Chalmers and the Strategic Area of Transport at Chalmers.
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| 31. |
- Gras, Laure-Lise, 1985, et al.
(author)
-
Active Child Models for Traffic Safety Research, Interim Report 1, October 2012
- 2012
-
Reports (other academic/artistic)abstract
- The project Active Child Models for Traffic Safety Research is funded by Folksams Forskningsstiftelse. The overall aim is to increase the safety of child car occupants and thereby reduce the number of traffic induced injuries in 3 to 12 year-old children. This will be done by creating a computer model of a child that includes active musculature. The model will be used to reproduce emergency manoeuvres with biofidelic response at low acceleration levels. Literature on child safety has been reviewed with a main focus on child numerical models. Very few child models exist and for most of them, their response is validated against Anthropometric Test Devices (ATDs) certification corridors and not paediatric data. Models of children and child sized ATDs are either finite element or multi body models. Finite element models are more likely to predict injuries and contacts, whereas multi body models can preferably be used to reproduce kinematics in long duration events like emergency manoeuvres. Because of this, it has thus been decided to first work with child multi body models in the MADYMO code (TASS, Rijswijk, the Netherlands). The models that will be studied are the 6 and 10 year-old child facet models and the Q6 and Hybrid III 6 year-old ATDs available in MADYMO as well as the 6 year-old pedestrian model previously developed by Jikuang Yang at Chalmers University of Technology. Simulation activities have been planned and the models’ responses will be analysed and compared with kinematics data of child volunteers in emergency manoeuvres and sled tests. Then, based on their performance, one model will be chosen to implement active musculature. Extra experimental data for tuning and validation of the model may be required. As a consequence, new experiments on child volunteers are planned, including the acquisition of muscular activity. The model response will be compared to those results. Based on the active child multi body model capability to reproduce pre-crash events, it will be discussed and decided in January 2013 whether to continue with a multi body model or start the same process with a finite element model. In the long term, the active child model will be used to reproduce both pre-crash and in-crash events and help understanding the protective principles of forward facing children and how they interact with current and future vehicle safety systems and child restraints.
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| 32. |
- Gras, Laure-Lise, 1985, et al.
(author)
-
Evaluation of 6 and 10 Year-Old Child Human Body Models in Emergency Events
- 2017
-
In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203 .- 1932-6203. ; 12:1, s. e0170377-
-
Journal article (peer-reviewed)abstract
- Emergency events can influence a child’s kinematics prior to a car-crash, and thus its interaction with the restraint system. Numerical Human Body Models (HBMs) can help understand the behaviour of children in emergency events. The kinematic responses of two child HBMs–MADYMO 6 and 10 year-old models–were evaluated and compared with child volunteers’ data during emergency events–braking and steering–with a focus on the forehead and sternum displacements. The response of the 6 year-old HBM was similar to the response of the 10 year-old HBM, however both models had a different response compared with the volunteers. The forward and lateral displacements were within the range of volunteer data up to approximately 0.3 s; but then, the HBMs head and sternum moved significantly downwards, while the volunteers experienced smaller displacement and tended to come back to their initial posture. Therefore, these HBMs, originally intended for crash simulations, are not too stiff and could be able to reproduce properly emergency events thanks, for instance, to postural control.
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| 33. |
- Holmqvist, Kristian, 1976, et al.
(författare)
-
Challenges in Steering Wheel Rim to Thorax Impacts Using Finite Element Hybrid III and Human Body Models for Heavy Vehicle Frontal Crash Applications
- 2010
-
Ingår i: International IRCOBI Conference on the Biomechanics of Impact. ; , s. 293-296
-
Konferensbidrag (refereegranskat)abstract
- A risk of severe injuries from steering wheel rim to thorax contacts has been identified in heavy vehicle frontal collisions. The objective of this study was to investigate the effects in changing the steering wheel rim tilt angle on the thorax of the Hybrid III and a human body model THUMS with respect to chest deflection and steering wheel rim contact interaction. It was found that the Hybrid III chest is more sensitive to changes in steering wheel tilt angle than the THUMS.
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| 34. |
- Iraeus, Johan, 1973, et al.
(författare)
-
Generic finite element models of human ribs, developed and validated for stiffness and strain prediction - To be used in rib fracture risk evaluation for the human population in vehicle crashes
- 2020
-
Ingår i: Journal of the Mechanical Behavior of Biomedical Materials. - : Elsevier BV. - 1751-6161 .- 1878-0180. ; 106
-
Tidskriftsartikel (refereegranskat)abstract
- To enable analysis of the risk of occupants sustaining rib fractures in a crash, generic finite element models of human ribs, one through twelve, were developed. The generic ribs representing an average sized male, were created based on data from several sources and publications. The generic ribs were validated for stiffness and strain predictions in anterior-posterior bending. Essentially, both predicted rib stiffness and rib strain, measured at six locations, were within one standard deviation of the average result in the physical tests. These generic finite elements ribs are suitable for strain-based rib fracture risk predictions, when loaded in anterior-posterior bending. To ensure that human variability is accounted for in future studies, a rib parametric study was conducted. This study shows that the rib cross-sectional height, i.e., the smallest of the cross-sectional dimensions, accounted for most of the strain variance during anterior-posterior loading of the ribs. Therefore, for future rib fracture risk predictions with morphed models of the human thorax, it is important to accurately address rib cross-sectional height.
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| 35. |
- Khodaei, Hamid, 1982, et al.
(författare)
-
Simulation of active skeletal muscle tissue with a transversely isotropic viscohyperelastic continuum material model
- 2013
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine. - : SAGE Publications. - 2041-3033 .- 0954-4119. ; 227:5, s. 571-580
-
Tidskriftsartikel (refereegranskat)abstract
- Human body models with biofidelic kinematics in vehicle pre-crash and crash simulations require a constitutive model of muscle tissue with both passive and active properties. Therefore, a transversely isotropic viscohyperelastic continuum material model with element-local fiber definition and activation capability is suggested for use with explicit finite element codes. Simulations of experiments with New Zealand rabbit's tibialis anterior muscle at three different strain rates were performed. Three different active force-length relations were used, where a robust performance of the material model was observed. The results were compared with the experimental data and the simulation results from a previous study, where the muscle tissue was modeled with a combination of discrete and continuum elements. The proposed material model compared favorably, and integrating the active properties of the muscle into a continuum material model opens for applications with complex muscle geometries.
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| 36. |
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| 37. |
- Larsson, Emma, 1991, et al.
(författare)
-
Active Human Body Model Predictions Compared to Volunteer Response in Experiments with Braking, Lane Change, and Combined Manoeuvres
- 2019
-
Ingår i: Conference proceedings International Research Council on the Biomechanics of Injury, IRCOBI. - 2235-3151. ; :S1-9, s. 349-369
-
Konferensbidrag (refereegranskat)abstract
- Active human body models are an important tool to study occupant interaction with safety systems in evasive manoeuvres such as braking and/or steering. In this study a finite element human body model with and without closed-loop active muscle control in the neck and lower trunk was compared to volunteer occupants in six different load cases with lane change, braking, and combined manoeuvres using standard and prepretensioned seat belts. Seven different muscle controllers, using two different muscle activation strategies based either on head and torso displacements or muscle length, and one with the controller turned off have been compared to volunteer kinematics. Cross-correlation analysis with CORA was used to evaluate the model biofidelity. The results show an improvement in CORA scores when using active muscles, compared to the model with muscle activity turned off, for one load case and similar CORA scores between the models for five load cases. CORA scores ranged from 0.78 to 0.88 for the active models and 0.70 to 0.82 from the model with muscles turned off. The active model gave a kinematic response with good biofidelity in lane change with braking, pure braking, and lane change with pre-pretensioned seat belt, but the biofidelity of the model was rated as fair in lane change with standard seat belt.
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| 38. |
- Mendoza-Vazquez, Manuel, 1979, et al.
(författare)
-
Construction and evaluation of thoracic injury risk curves for a finite element human body model in frontal car crashes
- 2015
-
Ingår i: Accident Analysis and Prevention. - : Elsevier BV. - 0001-4575. ; 85, s. 73-82
-
Tidskriftsartikel (refereegranskat)abstract
- There is a need to improve the protection to the thorax of occupants in frontal car crashes. Finite element human body models are a more detailed representation of humans than anthropomorphic test devices (ATDs). On the other hand, there is no clear consensus on the injury criteria and the thresholds to use with finite element human body models to predict rib fractures. The objective of this study was to establish a set of injury risk curves to predict rib fractures using a modified Total HUman Model for Safety (THUMS). Injury criteria at the global, structural and material levels were computed with a modified THUMS in matched Post Mortem Human Subjects (PMHSs) tests. Finally, the quality of each injury risk curve was determined. For the included PMHS tests and the modified THUMS, DcTHOR and shear stress were the criteria at the global and material levels that reached an acceptable quality. The injury risk curves at the structural level did not reach an acceptable quality.
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| 39. |
- Mendoza-Vazquez, Manuel, 1979, et al.
(författare)
-
EVALUATING THE THORACIC RESPONSE IN A HUMAN BODY MODEL, COMPARED TO CADAVER EXPERIMENTS
- 2011
-
Ingår i: Svenska Mekanikdagar 2011.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Fatalities caused by car accidents accounted for 1.2 million worldwide in 2004. Chestinjuries are the second death cause, after head injuries, in vehicle accidents. Devices topredict risk of injury are fundamental to develop and evaluate restraint systems that canmitigate the injury severity and reduce the fatalities. This can be achieved withmathematical Human Body Models (HBM). An HBM needs to be biofidelic, both in termsof size and biomechanical response. Herein, the biofidelity of the thorax region in an HBMis evaluated. The evaluation focuses on whole body kinematics and chest response duringfrontal car accidents.Finite element simulations with an HBM were performed with the code LS-DYNA [1].A modified version of Total HUman Model for Safety v3.0 (THUMS) [2] has been the basisfor the work presented here. THUMS was modified to improve its robustness andnumerical stability. The meshes of the rib cage, skin around the ribcage, and intercostalmuscles were refined. THUMS represents a 50th percentile male and has approximately150,000 elements. It was compared with cadaver pendulum impacts [3], table top tests [4],and sled tests [5]. The pendulum test consist of a cylinder with diameter 125 mm, mass of23.4 kg and an initial speed of 4.3 m/s impacting on the middle of the sternum. The tabletop tests included four loading conditions of the chest: hub, diagonal belt, double diagonalbelt, and distributed load. The sled test was performed at 40 km/h, using a three pointstandard seat belt.The model has been compared to cadaver experiments on different load cases, whichare representative of modern automotive restraint systems. In general, THUMS showed agood agreement with the experimental corridors for the pendulum and table top tests. Thechest response in the sled test differed for the lower chest, possibly due to the absence ofbiofidelic fracture simulations in the THUMS. After comparing the kinematic and dynamicresponses of THUMS with cadaver experiments it was concluded that the model isadequate to simulate the human response under frontal impacts. The next step is to identifyparameters that can predict the risk of rib fracture and then become a tool to evaluate newrestraint systems.
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| 40. |
- Mendoza-Vazquez, Manuel, 1979, et al.
(författare)
-
Evaluation of Thoracic Injury Criteria for THUMS Finite Element Human Body Model Using Real-World Crash Data
- 2014
-
Ingår i: IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury, 10-12 September, Berlin, Germany. ; :IRC-14-62, s. 528-541
-
Konferensbidrag (refereegranskat)abstract
- This study aims to compare the thoracic injury risk predicted by a modified THUMS with the risks predicted by an injury risk curve constructed based on real-world data. Since the injury risk curves for the modified THUMS were developed from reconstruction of post-mortem human subjects tests, it is of interest to investigate their performance in real-world crashes. For this purpose, an AIS2+ injury risk curve was constructed based on selected and representative frontal car crashes from the Volvo Cars' Traffic Statistical Accident Database. Six simulations with three different crash severities and two acceleration pulses for each severity were performed with THUMS in a detailed and representative interior vehicle model. The injury criteria Dmax, DcTHOR, shear stress and first principal strain in the ribs were computed with the modified THUMS and the risks were obtained from its previously developed injury risk curves. These risks were then compared to the risk from the real-world data. All four THUMS criteria predict higher risk compared to the risk predicted by the real-world injury risk curve. The risk estimated with Dmax was closest to the risk estimated by the injury risk curve based on real-world data.
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| 41. |
- Mendoza-Vazquez, Manuel, 1979, et al.
(författare)
-
Human rib response to different restraint systems in frontal impacts: a study using a human body model
- 2013
-
Ingår i: International Journal of Crashworthiness. - : Informa UK Limited. - 1358-8265 .- 1754-2111. ; 18:5, s. 516-529
-
Tidskriftsartikel (refereegranskat)abstract
- Finite-element human body models (FE-HBMs) can be used to evaluate restraint systems by predicting thoracic injury. The biofidelity assessment of an FE-HBM Total HUman Model for Safety (THUMS) 50th percentile male occupant and the characterisation of its rib response to loads from frontal car crashes are the objectives of this study. The rib-cage mesh of THUMS version 3.0 was refined to improve the shoulder-belt interaction, material properties of lungs and skin modified, and the model biofidelity assessed against tests representative of frontal crashes. The modified THUMS response improved with respect to the baseline model. The modified THUMS was used to analyse the rib loading in frontal impacts. The rib response included shear, torsion and bending in belt and airbag-like load cases. This indicates that a criterion based only on rib anteroposterior compression may not be enough to predict fractures and that a criterion should consider compression, torsion and shear.
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| 42. |
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| 43. |
- Meredith, Lauren, 1989, et al.
(författare)
-
Analyses of injuries to equestrians in a Swedish district over a 16-year period
- 2019
-
Ingår i: Translational Sports Medicine. - : Hindawi Limited. - 2573-8488. ; 2:5, s. 264-272
-
Tidskriftsartikel (refereegranskat)abstract
- Horse riding is a popular, yet dangerous, sport, and as such, horse-related injuries contribute considerably to the total number of people hospitalized every year. While some investigations have explored this public health issue, many have focused only on hospital registrations or insurance information, while neglecting the cases where the rider may have not required hospitalization. This study investigated the pattern of equestrian injuries in Sweden and examined factors for predicting hospitalized injuries, using visits to hospital, local medical centers, and public dental services. Data were gathered over a 16-year period at all medical facilities within Skaraborg, Sweden, and retrospectively reviewed. There were 7815 horse-related injury events during the study period. The sample of horse-related injuries were largely represented by females (88%) and those aged between 10 and 20 years old. Injuries commonly took place during private/leisure time (90.8%) and in the afternoon. Logistic regression analysis found that older riders were significantly more likely to be admitted to hospital (OR = 1.013), while female riders were less likely to be admitted than males (OR = 0.739). The numbers of people registering at medical facilities due to horse-related injuries are increasing. Therefore, improved intervention measures must be further investigated.
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| 44. |
- Meredith, Lauren, 1989, et al.
(författare)
-
Epidemiology of Equestrian Accidents: a Literature Review
- 2018
-
Ingår i: The Internet Journal of Allied Health Sciences & Practice. - 1540-580X. ; 17:1
-
Forskningsöversikt (refereegranskat)abstract
- Purpose: This manuscript aimed to present a review of the literature pertaining to horse riding and other horse-related injuries. Method: A review of the literature was performed, searching for appropriate terms with regard to horse accidents, horse riding injuries and protective clothing for the horse riding context. The literature review search returned 151 relevant full-text articles, with 71 of these detailing the overall injury epidemiology of horse-related accidents. Most of these studies were conducted in the USA and used a retrospective review of hospital data methodology. Results: Of the 71 articles investigated, 60 suggested that those most frequently involved in horse-related accidents are young females and 97% of papers investigating injury mechanisms found the most commonly involved was a fall from horseback. It was suggested in multiple studies that these injury events mostly occurred in warm weather conditions, when the horse behaved in an unexpected manner. Injury type and location varied by the primary mechanism of injury, but frequently-involved body regions were the head and upper extremities, and the most common injuries observed were fractures and soft tissue injuries. Neurological trauma was reported by all relevant studies to be the most frequent cause of fatality. Conclusion: Some improvements in horse-related accident numbers and outcomes have been observed with the development and introduction of protective devices such as helmets and vests. Yet despite the benefits of helmet and vest usage, there is evidence to suggest helmets do not perform as well as they could. Further work could investigate improvements in safety measures and risk factors associated with fatalities.
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| 45. |
- Mroz, Krystoffer, 1966, et al.
(författare)
-
Comparison of Hybrid III and human body models in evaluating thoracic response for various seat belt and airbag loading conditions
- 2010
-
Ingår i: IRCOBI Conference. - 9783033025509 ; , s. 265-279
-
Konferensbidrag (refereegranskat)abstract
- Thoracic responses between the Hybrid III model and the THUMS human body model were compared in three frontal impact severities for two belt (3-point and criss-cross), two belt load limiter (constant and degressive) and two airbag types (symmetric and non-symmetric). The thoracic responses were evaluated by measurements of chest deflections (mid-sternum and multi-point measured), chest excursions and, for the human body model, supplemented by maximum rib strains. For the 3-point belt, an overall correlation was found between Hybrid III and THUMS chest deflections and excursions as well as between THUMS multi-point chest deflections and rib strains. For the criss-cross belt, Hybrid III chest deflections increased and THUMS rib strains decreased. For the non-symmetric airbag, Hybrid III and THUMS chest deflections decreased.
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| 46. |
- Naseri, Hosein, 1987, et al.
(författare)
-
A Nonlinear Viscoelastic Model for Adipose Tissue Representing Tissue Response at a Wide Range of Strain Rates and High Strain Levels
- 2018
-
Ingår i: Journal of Biomechanical Engineering. - : ASME International. - 0148-0731 .- 1528-8951. ; 140:4
-
Tidskriftsartikel (refereegranskat)abstract
- Finite element human body models are nowdays commonly used to simulate pre- and in- crash occupant response in order to develop advanced safety systems. In this study a biofidelic model for adipose tissue is developed for this application. It is a nonlinear viscoelastic model based on the Reese et al. formulation. The model is formulated in a large strain framework and applied for finite element simulation of two types of experiments: rheological experiments and ramped-displacement experiments. The adipose tissue behavior in both experiments are represented well by this model. It indicates the capability of the model to be used in large deformation and wide range of strain rates for application in human body models.
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| 47. |
- Naseri, Hosein, 1987, et al.
(författare)
-
Modeling the mechanical behavior of adipose tissue
- 2016
-
Ingår i: 29th Nordic Seminar on Computational Mechanics, NSCM-29, R. Larsson (Ed.). ; , s. 4 pages-
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this study a nonlinear viscoelastic model for adipose tissue based on the Reese-Govindjee formulation is presented. The model is formulated in a large strain framework and is applied for 3D finite element simulation of rheometer experiment.
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| 48. |
- Olafsdottir, Jóna Marin, 1985, et al.
(författare)
-
Cervical Muscle Responses to Multi-Directional Perturbations
- 2014
-
Ingår i: 7th World Congress of Biomechanics.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Numerical human models are widely used in the design process and evaluation of passive and active vehicle safety systems in pre-crash and crash situations. Development and validation of human models that simulate neuromuscular control requires information on muscle activation patterns and contraction levels for different loading directions. Due to the lack of experimental data on cervical muscle recruitment strategies, the aim of this study was to provide activation patterns for superficial and deep cervical muscles during multidirectional perturbations.Eight volunteers received three perturbations (apeak=1.5g, ∆v=0.5m/s) in each of eight different directions while seated unrestrained on a sled-mounted car seat without a head restraint. Volunteers received no warning of perturbation onset. Electromyographic (EMG) activity was measured with wire electrodes inserted into the left sternocleidomastoid (SCM), trapezius (Trap), levator scapulae (LS), splenius capitis (SPL), semispinalis capitis (SCap), semispinalis cervicis (SCerv), and multifidus (Multi) muscles, and with surface electrodes over the sternohyoid (STH) muscle. All EMG signals were normalized with maximum voluntary isometric contraction activity.All median muscle activities were below 5%MVC before perturbation onset. During perturbation, most muscles showed distinctive activation patterns consistent with their anatomical location and function. Anterior muscles (SCM, STH) activated to counteract head extension and posterior muscles, except SPL, activated to counteract flexion (Figure). Although with different levels of contraction, SCap, SCerv, and Multi activated synergistically with the highest activity (89%, 50%, and 36%MVC respectively, 110ms after perturbation onset) during rearward and ipsilateral rearward oblique perturbations. Activation levels were generally five times lower in other directions. Despite its posterior location, SPL had activities between 19%MVC and 27%MVC during forward, forward oblique and lateral perturbations, but
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| 49. |
- Olafsdottir, Jóna Marin, 1985, et al.
(författare)
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Dynamic Spatial Tuning of Cervical Muscle Reflexes to Multidirectional Seated Perturbations
- 2015
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Ingår i: Spine. - 0362-2436 .- 1528-1159. ; 40:4, s. E211-E219
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Tidskriftsartikel (refereegranskat)abstract
- Study Design. Human volunteers were exposed experimentally to multidirectional seated perturbations.Objective. To determine the activation patterns, spatial distribution and preferred directions of reflexively activated cervical muscles for human model development and validation.Summary of Background Data. Models of the human head and neck are used to predict occupant kinematics and injuries in motor vehicle collisions. Because of a dearth of relevant experimental data, few models use activation schemes based on in vivo recordings of muscle activation and instead assume uniform activation levels for all muscles within presumed agonist or antagonist groups. Data recorded from individual cervical muscles are needed to validate or refute this assumption.Methods. Eight subjects (6 males, 2 females) were exposed to seated perturbations in 8 directions. Electromyography was measured with wire electrodes inserted into the sternocleidomastoid, trapezius, levator scapulae, splenius capitis, semispinalis capitis, semispinalis cervicis, and multifidus muscles. Surface electrodes were used to measure sternohyoid activity. Muscle activity evoked by the perturbations was normalized with recordings from maximum voluntary contractions.Results. The multidirectional perturbations produced activation patterns that varied with direction within and between muscles. Sternocleidomastoid and sternohyoid activated similarly in forward and forward oblique directions. The semispinalis capitis, semispinalis cervicis, and multifidus exhibited similar spatial patterns and preferred directions, but varied in activation levels. Levator scapulae and trapezius activity generally remained low, and splenius capitis activity varied widely between subjects.Conclusion. All muscles showed muscle- and direction-specific contraction levels. Models should implement muscle- and direction-specific activation schemes during simulations of the head and neck responses to omnidirectional horizontal perturbations where muscle forces influence kinematics, such as during emergency maneuvers and low-severity crashes.Level of Evidence: N/A
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| 50. |
- Olafsdottir, Jóna Marin, 1985, et al.
(författare)
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Modelling reflex recruitment of neck muscles in a finite element human body model for simulating omnidirectional head kinematics
- 2019
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Ingår i: Conference proceedings International Research Council on the Biomechanics of Injury, IRCOBI. - 2235-3151. ; , s. 308-323
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Konferensbidrag (refereegranskat)abstract
- Numerical human body models that can predict occupant head and neck responses are essential for the development and assessment of motor vehicle safety systems. Including the contribution of neck muscle responses is needed to improve model predictions, in particular during simulated pre-crash manoeuvers. While a general purpose model that can predict head-neck kinematics in various pre-crash conditions (e.g. emergency braking and steering) is needed most current models have been limited to predictions of longitudinal motion (e.g. during emergency braking). We developed a method for simulating muscle recruitment in a finite element human body model for omnidirectional head-neck kinematics predictions. A neural control scheme that uses kinematics and muscle length feedback to determine the activation level in individual muscle elements was implemented. The control scheme included a novel approach to determine load sharing between muscles based on experimental data from human subjects in dynamic conditions. Multidirectional 1 g loading conditions were simulated to assess the effect of muscle recruitment on head and neck kinematics in multiple directions and to evaluate the predicted spatial tuning of recruitment for selected muscles. Simulation results demonstrate that including both kinematics and muscle length feedback reduces head and internal neck motion induced from external 1 g loading.
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