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- Östh, Jonas, 1983, et al.
(författare)
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A female head–neck model for rear impact simulations
- 2017
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Ingår i: Journal of Biomechanics. - : Elsevier BV. - 0021-9290 .- 1873-2380. ; 51, s. 49-56
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Tidskriftsartikel (refereegranskat)abstract
- Several mathematical cervical models of the 50th percentile male have been developed and used for impact biomechanics research. However, for the 50th percentile female no similar modelling efforts have been made, despite females being subject to a higher risk of soft tissue neck injuries. This is a limitation for the development of automotive protective systems addressing Whiplash Associated Disorders (WADs), most commonly caused in rear impacts, as the risk for females sustaining WAD symptoms is double that of males.In this study, a finite element head and neck model of a 50th percentile female was validated in rear impacts. A previously validated ligamentous cervical spine model was complemented with a rigid body head, soft tissues and muscles. In both physiological flexion-extension motions and simulated rear impacts, the kinematic response at segment level was comparable to that of human subjects.Evaluation of ligament stress levels in simulations with varied initial cervical curvature revealed that if an individual assumes a more lordotic posture than the neutral, a higher risk of WAD might occur in rear impact. The female head and neck model, together with a kinematical whole body model which is under development, addresses a need for tools for assessment of automotive protection systems for the group which is at the highest risk to sustain WAD.
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| 3. |
- Brolin, Karin, 1974, et al.
(författare)
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HUMAN BODY MODELING FOR APPLIED TRAFFIC SAFETY
- 2011
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Ingår i: SVENSKA MEKANIKDAGAR, 13-15 JUNI, 2011, Göteborg.
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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.
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| 8. |
- Ghosh, Pronoy, et al.
(författare)
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A proposal for integrating pre-crash vehicle dynamics into occupant injury protection evaluation of small electric vehicles
- 2015
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Ingår i: 2015 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury. ; , s. 767-782
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Konferensbidrag (refereegranskat)abstract
- This research addresses integration of pre‐crash dynamics into crash phase using two differenthuman body models. The methodology discussed is a manual way of utilizing data from two differentsimulations and developing an interlinking chain of data to explore feasibility of integration.The crash pulse was based on a collision scenario of 35 km/h (MPDB – 35 km/h ‐ 30⁰ ‐ 50% offsetconfiguration and a generic 1g braking pulse for the pre‐crash phase was considered for AutonomousEmergency Braking events. Data transfer from the pre‐crash to in‐crash phase involved position, velocity, stressand strains for different body parts to introduce pre‐crash dynamic effects. Two parameters, chest compressionand contact force of Human Body Models with airbag, were chosen to assess risk of injures to head and thorax.Simulations with different crash initiation times (650ms, 830 ms and 970 ms) were used to assess response ofrestraint systems to changing inertial loads of occupants.The simulations results indicated that this method of data transfer is viable and can be used to assess injuryrisks for occupant. The coupling of two different simulations with different models could definitely yieldaccurate results, but, is sufficient to ensure realistic occupant kinematics and reasonable injury predictioncapabilities.
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| 9. |
- Holmqvist, Kristian, 1976, et al.
(författare)
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IMPROVING HYBRID III INJURY ASSESSMENT IN STEERING WHEEL RIM TO CHEST IMPACTS USING RESPONSES FROM FINITE ELEMENT HYBRID III AND HUMAN BODY MODEL
- 2014
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 15:2, s. 196-205
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The main aim of this study was to improve the quality of injury risk assessments in steering wheel rim to chest impacts when using the Hybrid III crash test dummy in frontal heavy goods vehicle (HGV) collision tests. Correction factors for chest injury criteria were calculated as the model chest injury parameter ratios between finite element (FE) Hybrid III, evaluated in relevant load cases, and the Total Human Model for Safety (THUMS). This is proposed to be used to compensate Hybrid III measurements in crash tests where steering wheel rim to chest impacts occur.Methods: The study was conducted in an FE environment using an FE-Hybrid III model and the THUMS. Two impactor shapes were used, a circular hub and a long, thin horizontal bar. Chest impacts at velocities ranging from 3.0 to 6.0m/s were simulated at 3 impact height levels. A ratio between FE-Hybrid III and THUMS chest injury parameters, maximum chest compression C-max, and maximum viscous criterion VCmax, were calculated for the different chest impact conditions to form a set of correction factors. The definition of the correction factor is based on the assumption that the response from a circular hub impact to the middle of the chest is well characterized and that injury risk measures are independent of impact height. The current limits for these chest injury criteria were used as a basis to develop correction factors that compensate for the limitations in biofidelity of the Hybrid III in steering wheel rim to chest impacts.Results: The hub and bar impactors produced considerably higher C-max and VCmax responses in the THUMS compared to the FE-Hybrid III. The correction factor for the responses of the FE-Hybrid III showed that the criteria responses for the bar impactor were consistently overestimated. Ratios based on Hybrid III and THUMS responses provided correction factors for the Hybrid III responses ranging from 0.84 to 0.93. These factors can be used to estimate C-max and VCmax values when the Hybrid III is used in crash tests for which steering wheel rim to chest interaction occurs.Conclusions: For the FE-Hybrid III, bar impacts caused higher chest deflection compared to hub impacts, although the contrary results were obtained with the more humanlike THUMS. Correction factors were developed that can be used to correct the Hybrid III chest responses. Higher injury criteria capping limits for steering wheel impacts are acceptable. Supplemental materials are available for this article. Go to the publisher's online edition of Traffic Injury Prevention to view the supplemental file.
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