Development and Validation of the Total HUman Model for Safety (THUMS) Toward Further Understanding of Occupant Injury Mechanisms in Precrash and During Crash

Abstract

Objective: Active safety devices such as automatic emergency brake (AEB) and precrash seat belt have the potential to accomplish further reduction in the number of the fatalities due to automotive accidents. However, their effectiveness should be investigated by more accurate estimations of their interaction with human bodies. Computational human body models are suitable for investigation, especially considering muscular tone effects on occupant motions and injury outcomes. However, the conventional modeling approaches such as multibody models and detailed finite element (FE) models have advantages and disadvantages in computational costs and injury predictions considering muscular tone effects. The objective of this study is to develop and validate a human body FE model with whole body muscles, which can be used for the detailed investigation of interaction between human bodies and vehicular structures including some safety devices precrash and during a crash with relatively low computational costs.Methods: In this study, we developed a human body FE model called THUMS (Total HUman Model for Safety) with a body size of 50th percentile adult male (AM50) and a sitting posture. The model has anatomical structures of bones, ligaments, muscles, brain, and internal organs. The total number of elements is 281,260, which would realize relatively low computational costs. Deformable material models were assigned to all body parts. The muscle-tendon complexes were modeled by truss elements with Hill-type muscle material and seat belt elements with tension-only material. The THUMS was validated against 35 series of cadaver or volunteer test data on frontal, lateral, and rear impacts. Model validations for 15 series of cadaver test data associated with frontal impacts are presented in this article. The THUMS with a vehicle sled model was applied to investigate effects of muscle activations on occupant kinematics and injury outcomes in specific frontal impact situations with AEB.Results and Conclusions: In the validations using 5 series of cadaver test data, force-time curves predicted by the THUMS were quantitatively evaluated using correlation and analysis (CORA), which showed good or acceptable agreement with cadaver test data in most cases. The investigation of muscular effects showed that muscle activation levels and timing had significant effects on occupant kinematics and injury outcomes. Although further studies on accident injury reconstruction are needed, the THUMS has the potential for predictions of occupant kinematics and injury outcomes considering muscular tone effects with relatively low computational costs.

Quantitative Analysis of Tissue Damage Evolution in Porcine Liver With Interrupted Mechanical Testing Under Tension, Compression, and Shear

“…Over the years, there has been much progress in the development of FE models for impact and injury predictions. FE models of various human body regions including the lower extremities, abdomen, pelvis, thorax, neck, and head have been generated as well as full body models such as total human model for safety and global human body models consortium [24][25][26][27][28][29][30][31][32]. However, to this end, a noticeable gap exists in the understanding of injury thresholds for these soft tissues.…”

Finite Element Analysis for Investigating the Effects of Muscle Activation on Head-neck Injury Risks of Drivers Rear-ended by a Car after an Autonomous Emergency Braking

“…THUMS includes bones, ligaments, muscles, skin, brain, and internal organs such as lung and liver, and can be used for the injury estimation of each organ. The model was validated against 36 series of cadaveric or volunteer test data of the human body responses for frontal, side, and rear impacts, and the results showed good agreement with the test data (4) (5) . In addition, the THUMS includes 262 muscle bar elements modeled by Hill type muscle contractile material properties, and can reproduce the driver's muscle activation conditions by inputting the activation time history curves to individual muscles of the entire body (4) .…”

Mechanical Modeling of Healthy and Diseased Calcaneal Fat Pad Surrogates

“…To date, a plethora of surrogate models exist for soft tissues such as the calcaneal heel pad [19,20], which have been characterized using indentation systems (measuring external load–deformation responses) [20], imaging (for internal strain measurements) [21], and experienced palpatory testing [22]. These surrogates have been used in anthropomorphic test devices for the study of injury risks associated with the lower extremity due to blast loading [14,19,23,24] and high impact loadings sustained in vehicular crashes [25,26]. Also, surrogate models have been employed in several studies to characterize the effect of personal protection equipment [27], and orthotic interventions for injury prevention [28,29].…”