| 1. |
- Carlsson, Stina, 1967, et al.
(författare)
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Volunteer occupant kinematics during driver initiated and autonomous braking when driving in real traffic environments
- 2011
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Ingår i: 2011 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury IRCOBI, 14 - 16 September 2011, Krakow, Polen. ; 2011, s. 125-136
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Konferensbidrag (refereegranskat)abstract
- When a vehicle is braking, the occupants are subjected to longitudinal forces which may influence their positions. The aim of this paper is to quantify the driver and passenger kinematics during medium harsh braking while driving in real traffic and to identify the influencing parameters.The overall motions were relatively small during braking and the effect of seat belt locking was obvious. Mean forward motions were 55 ±26 mm for the chest and 97 ±47 mm for the head. This study indicates that several properties influence forward motion. Taller volunteers had a larger forward motion; females had a larger forward motion than males of the same sitting height. Passengers exhibited larger motions than drivers for most of the volunteers.The result provides a deeper understanding of pre-impact conditions and adds knowledge to further improve the interaction of active and passive safety systems. It also provides valuable validation data for low-g occupant models, which can be used in studies of the effect of pre-impact braking on restraint interaction.
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| 2. |
- Mendoza-Vazquez, Manuel, 1979, et al.
(författare)
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Evaluation of Thoracic Injury Criteria for THUMS Finite Element Human Body Model Using Real-World Crash Data
- 2014
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Ingår i: IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury, 10-12 September, Berlin, Germany. ; :IRC-14-62, s. 528-541
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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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| 3. |
- Rostami, Elham, 1979-, et al.
(författare)
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A Model for Mild Traumatic Brain Injury that Induces Limited Transient Memory Impairment and Increased Levels of Axon Related Serum Biomarkers
- 2012
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Ingår i: Frontiers in Neurology. - : Frontiers Media SA. - 1664-2295. ; 3, s. 115-
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Tidskriftsartikel (refereegranskat)abstract
- Mild traumatic brain injury (mTBI) is one of the most common neuronal insults and can lead to long-term disabilities. mTBI occurs when the head is exposed to a rapid acceleration-deceleration movement triggering axonal injuries. Our limited understanding of the underlying pathological changes makes it difficult to predict the outcome of mTBI. In this study we used a scalable rat model for rotational acceleration TBI, previously characterized for the threshold of axonal pathology. We have analyzed whether a TBI just above the defined threshold would induce any detectable behavioral changes and/or changes in serum biomarkers. The effect of injury on sensory motor functions, memory and anxiety were assessed by beam walking, radial arms maze and elevated plus maze at 3–7 days following TBI. The only behavioral deficits found were transient impairments in working and reference memory. Blood serum was analyzed at 1, 3, and 14 days after injury for changes in selected protein biomarkers. Serum levels of neurofilament heavy chain and Tau, as well as S100B and myelin basic protein showed significant increases in the injured animals at all time points. No signs of macroscopic injuries such as intracerebral hematomas or contusions were found. Amyloid precursor protein immunostaining indicated axonal injuries at all time points analyzed. In summary, this model mimics some of the key symptoms of mTBI, such as transient memory impairment, which is paralleled by an increase in serum biomarkers. Our findings suggest that serum biomarkers may be used to detect mTBI. The model provides a suitable foundation for further investigation of the underlying pathology of mTBI.
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| 4. |
- Schmitt, Kai Uwe, et al.
(författare)
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Seat testing to investigate the female neck injury risk : preliminary results using a new female dummy prototype
- 2012
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Ingår i: Proceedings: IRCOBI Conference; September 12–14; Trinity College, Dublin, Ireland. ; , s. IRC 12-33-
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Konferensbidrag (refereegranskat)abstract
- Dynamic performance tests are conducted to assess the neck injury risk. To date seats are assessed based on sled tests mostly using a BioRID which is based on the 50%ile male anthropometry. Since females sustain whiplash associated disorders (WAD) more often than males, their injury risk needs to be addressed as well.
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| 5. |
- Östh, Jonas, 1983, et al.
(författare)
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The Occupant Response to Autonomous Braking: A Modelling Approach That Accounts for Active Musculature
- 2012
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 13:3, s. 265-277
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim of this study is to model occupant kinematics in an autonomous braking event by using a Finite Element (FE) Human Body Model (HBM) with active muscles, as a step towards HBMs that can be used for injury prediction in integrated pre-crash and crash simulations.Methods: Trunk and neck musculature was added to an existing FE HBM. Active muscle responses were achieved using a simplified implementation of three feedback controllers for: the head angle, the neck angle, and the angle of the lumbar spine. The HBM was compared with volunteer responses in sled tests with 10 ms−2 deceleration over 0.2 s and in 1.4 s autonomous braking interventions with a peak deceleration of 6.7 ms−2.Results: The HBM captures the characteristics of the kinematics of volunteers in sled tests. Peak forward displacements have the same timing as for the volunteers, and lumbar muscle activation timing matches data from one of the volunteers. The responses of volunteers in autonomous braking interventions are mainly small head rotations and translational motions. This is captured by the HBM controller objective, which is to maintain the initial angular positions. The HBM response with active muscles is within +/- 1 standard deviation of the average volunteer response with respect to head displacements and angular rotation.Conclusions: With the implementation of feedback control of active musculature in an FE HBM, it is possible to model the occupant response to autonomous braking interventions. The lumbar controller is important for the simulations of lap-belt restrained occupants; it is less important for the kinematics of occupants with a modern three point seat belt. Increasing head and neck controller gains gives a better correlation for head rotation, while it reduces the vertical head displacement and introduces oscillations.
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| 6. |
- Angeria, Maria, et al.
(författare)
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Experimental Animal Models for Studies on the Mechanisms of Blast-induced Neurotrauma
- 2012
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Ingår i: Frontiers in Neurology. - : Frontiers Media SA. - 1664-2295. ; 3:30
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Tidskriftsartikel (refereegranskat)abstract
- A blast injury is a complex type of physical trauma resulting from the detonation of explosive compounds and has become an important issue due to the use of improvised explosive devices (IED) in current military conflicts. Blast-induced neurotrauma (BINT) is a major concern in contemporary military medicine and includes a variety of injuries that range from mild to lethal. Extreme forces and their complex propagation characterize BINT. Modern body protection and the development of armored military vehicles can be assumed to have changed the outcome of BINT. Primary blast injuries are caused by overpressure waves whereas secondary, tertiary, and quaternary blast injuries can have more varied origins such as the impact of fragments, abnormal movements, or heat. The characteristics of the blast wave can be assumed to be significantly different in open field detonations compared to explosions in a confined space, such an armored vehicle. Important parameters include peak pressure, duration, and shape of the pulse. Reflections from walls and armor can make the prediction of effects in individual cases very complex. Epidemiological data do not contain information of the comparative importance of the different blast mechanisms. It is therefore important to generate data in carefully designed animal models. Such models can be selective reproductions of a primary blast, penetrating injuries from fragments, acceleration movements, or combinations of such mechanisms. It is of crucial importance that the physical parameters of the employed models are well characterized so that the experiments can be reproduced in different laboratory settings. Ideally, pressure recordings should be calibrated by using the same equipment in several laboratories. With carefully designed models and thoroughly evaluated animal data it should be possible to achieve a translation of data between animal and clinical data. Imaging and computer simulation represent a possible link between experiments and studies of human cases. However, in order for mathematical simulations to be completely useful, the predictions will most likely have to be validated by detailed data from animal experiments. Some aspects of BINT can conceivably be studied in vitro. However, factors such as systemic response, brain edema, inflammation, vasospasm, or changes in synaptic transmission and behavior must be evaluated in experimental animals. Against this background, it is necessary that such animal experiments are carefully developed imitations of actual components in the blast injury. This paper describes and discusses examples of different designs of experimental models relevant to BINT.
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| 7. |
- Antona, Jacobo, 1981, et al.
(författare)
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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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Ingår i: IRCOBI Conference. - 2235-3151. ; :IRC-13-55, s. 509-522
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Konferensbidrag (refereegranskat)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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| 8. |
- Antona, Jacobo, 1981, et al.
(författare)
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Rat brain kinematics and tissue strains associated to Diffuse Axonal Injuries induced by head rotational acceleration
- 2013
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Ingår i: Proceedings of Computational Engineering Conference JSCES. ; 18
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An anatomically detailed finite element model of a rat head-neck complex has been developed from medical images. The model incorporates material properties from tissue indentation test data captured in the coronal plane from seven brain regions to account for non-homogeneity. The local brain-skull relative displacement has been validated against local brain-slip experimental data in which a thin pin was entered the cortex and rigidly attached to the skull prior to impact. The model is being used to improve the understanding of brain rotational kinematics and to develop brain tissue injury thresholds for Diffuse Axonal Injuries as detected through immuno-histology.
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| 9. |
- Antona, Jacobo, 1981, et al.
(författare)
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Reanalysis of Monkey Head Concussion Experiment Data Using a Novel Monkey Finite Element Model to Develop Brain Tissue Injury Reference Values
- 2012
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Ingår i: Proceeding of the 2012 International IRCOBI Conference on the Biomechanics of Impact. - 2235-3151. ; 2012, s. 441-454
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Konferensbidrag (refereegranskat)abstract
- A new method has been applied to develop a Finite Element (FE) model of the head‐ neck complexof Macaque monkey from medical images. The skull, brain and flesh have been validated based on tissue andcomponent experimental data from literature. The kinematics of the head during occipital impacts have beenvalidated against a sub‐set of head impact experiments carried out in the past at the Japan AutomobileResearch Institute (JARI). The validated model has been used to simulate 19 occipital impacts case‐by‐case. Thecorrelation between obtained peak values for a number of mechanical parameters of the different brain regionsand the occurrence of concussion in the experiments was analysed. Maximum principal strain in the brainstemshowed significant correlation to concussion; 21% strain was associated with a probability of 50% risk forconcussion. The developed model and the presented results constitute the first step towards the developmentof a tissue level injury criterion for humans that is based on experimental animal data.
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| 10. |
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