| 1. |
- Brolin, Karin, 1974, et al.
(författare)
-
Aiming for an average female virtual human body model for seat performance assessment in rear-end impacts
- 2015
-
Ingår i: The 24th ESV Conference Proceedings.
-
Konferensbidrag (refereegranskat)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.
|
|
| 2. |
- Brolin, Karin, 1974, et al.
(författare)
-
Development of an Active 6-Year-Old Child Human Body Model for Simulation of Emergency Events
- 2015
-
Ingår i: 2015 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury. ; :IRC-15-74, s. 689-700
-
Konferensbidrag (refereegranskat)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.
|
|
| 3. |
- Brolin, Karin, 1974, et al.
(författare)
-
Evaluation at low g-level loading
- 2014
-
Ingår i: 5th International Symposium on Human Modelling and Simulation in Automotive Engineering, Munich, Germany, October 16-17, 2014.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 4. |
- Brolin, Karin, 1974, et al.
(författare)
-
Finite Element Musculoskeletal Model with Feedback Control to Simulate Spinal Postural Responses
- 2014
-
Ingår i: 7th World Congress of Biomechanics. ; July 6-11, Boston, USA:18-14
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)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.
|
|
| 5. |
- Brolin, Karin, 1974, et al.
(författare)
-
HUMAN BODY MODELING FOR APPLIED TRAFFIC SAFETY
- 2011
-
Ingår i: SVENSKA MEKANIKDAGAR, 13-15 JUNI, 2011, Göteborg.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)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.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Brolin, Karin, 1974, et al.
(författare)
-
Towards omni-directional active human body models
- 2016
-
Ingår i: 6th International Symposium on Human Modeling and Simulation in Automotive Engineering, Heidelberg, GERMANY, October 20-21.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 10. |
- Cutcliffe, Hattie, et al.
(författare)
-
Gender Differences in Occupant Posture and Muscle Activity with Motorized Seat Belts
- 2015
-
Ingår i: The 24th ESV Conference Proceedings.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)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.
|
|
