Analysis of running child pedestrians impacted by a vehicle using rigid-body models and optimization techniques

Untaroiu, Costin D.; Crandall, Jeffrey Richard; Takahashi, Yoshitomo; Okamoto, Masayoshi; Ito, Osamu; Fredriksson, Rikard

doi:10.1016/j.ssci.2009.09.003

Cited by 48 publications

(20 citation statements)

References 22 publications

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“…49,54 Since the strain rate effect of bone is not well-understood, more mechanical tests (e.g., coupon tests 25 ) in various loading (compression, tension, and shear) and rates are recommended. Using these new test data, parameters of an existing material model with strain-rate effect could be identified using FE simulations and optimization 53,56 or a new material model can be defined in FE software. 23 These strain rate dependent material models will definitely extend the applicability range of the bone models from automotive applications towards quasi-static and blast loadings which correspond to lower and higher deformation rates than those observed in automotive impacts.…”

Section: Discussionmentioning

confidence: 99%

A Finite Element Model of the Lower Limb for Simulating Automotive Impacts

2012

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A finite element (FE) model of a vehicle occupant's lower limb was developed in this study to improve understanding of injury mechanisms during traffic crashes. The reconstructed geometry of a male volunteer close to the anthropometry of a 50th percentile male was meshed using mostly hexahedral and quadrilateral elements to enhance the computational efficiency of the model. The material and structural properties were selected based on a synthesis of current knowledge of the constitutive models for each tissue. The models of the femur, tibia, and leg were validated against Post-Mortem Human Surrogate (PMHS) data in various loading conditions which generates the bone fractures observed in traffic accidents. The model was then used to investigate the tolerances of femur and tibia under axial compression and bending. It was shown that the bending moment induced by the axial force reduced the bone tolerance significantly more under posterior-anterior (PA) loading than under anterior-posterior (AP) loading. It is believed that the current lower limb models could be used in defining advanced injury criteria of the lower limb and in various applications as an alternative to physical testing, which may require complex setups and high cost.

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Section: Discussionmentioning

confidence: 99%

A Finite Element Model of the Lower Limb for Simulating Automotive Impacts

2012

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“…The WBIM was evaluated using the customized Excel TM routine and minimization of WBIM was defined as the optimization objective function. A multi-objective genetic algorithm (MOGA) was used to adapt the initial design populations over successive generations Untaroiu et al, 2009Untaroiu et al, , 2010 Since the problem in hand consisted of four design variables and a single objective function, a relatively coarse mesh of initial population produced the global objective solution without considerations into Pareto solution sets. The convergence to a uni-modal solution in the given design space required an initial population of 20 designs sets adapted over 30 generations for each of the restraint optimizations.…”

Section: Appendix B Restraint Optimization Routinementioning

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Influence of pre-collision occupant parameters on injury outcome in a frontal collision

Bose

Crandall

Untaroiu

et al. 2010

Accident Analysis & Prevention

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“…However, the applicability of these algorithms in complex optimisation problems is limited due to several shortcomings: (1) requirement of a huge computational effort to make a complete search of the design space, (2) difficulties for some algorithms to identify when the global minimum was achieved and to stop searching [18] and (3) specific format of optimisation problem required to be numerically implemented (cf, semi-definite programming techniques noted in [27]). Therefore, engineering optimisation problems having complex mathematical models such as FE models [5,32] and multi-body models [31,33] are usually solved using heuristics algorithms. While these algorithms cannot guarantee reaching the optimal solution, they can find a good solution possibly close to the global optimum by examining a large discrete configuration space in a reasonable time frame.…”

Section: Materials Identification and Sensitivity Study Of A Cortical mentioning

confidence: 99%

A numerical investigation of mid-femoral injury tolerance in axial compression and bending loading

Untaroiu

2010

International Journal of Crashworthiness

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Bone fractures occur frequently at mid-shaft femoral site of the front seat vehicle occupants during frontal and offset automotive crashes. A numerical investigation of femoral shaft tolerance under axial and bending loading corresponding to traffic accidents is presented in the current study. A subject specific finite element (FE) model of a femur is developed and the parameters of two material models of cortical bone (isotropic elastic-plastic and elastic transversally isotropic) are identified based on three-point bending test data using optimisation techniques. A Monte Carlo analysis is performed on a surface approximation of the optimised models over a domain of +/− 20% of the optimised parameter values and showed that the elastic moduli of femur are the most influential parameters on the bone stiffness curve prior to bone fracture. The mid-shaft femoral tolerance curves demonstrate sensitivity with respect to the impact direction of transversal load due to the initial curvature of the femur, but insignificant dependence on the material model, or the failure criteria used for femoral cortical bone. The results highlight the predominant role of bending in a combined axial-bending loading of the femur, which may be used in redefining the current injury criteria of femur used in anthropometric test devices.

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Analysis of running child pedestrians impacted by a vehicle using rigid-body models and optimization techniques

Cited by 48 publications

References 22 publications

A Finite Element Model of the Lower Limb for Simulating Automotive Impacts

A Finite Element Model of the Lower Limb for Simulating Automotive Impacts

Influence of pre-collision occupant parameters on injury outcome in a frontal collision

A numerical investigation of mid-femoral injury tolerance in axial compression and bending loading

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