THUMS (Total human model for safety) [Watanabe et al¹] is a finite element model of human body developed to study various injury mechanisms and for use as a substitute for crash test dummies. The development team of Toyota Central R&D Labs (TCRDL) has validated different parts of this model against experimental data available in literature. Neck response data for different impact conditions is available in Mertz and Patrick^2,3 and McElhaney et.al^4,5. A preliminary validation of the neck model in Thums, against some of these tests, has been presented by the TCRDL group [Oshita et.al⁶] but no extensive validation has been reported for the variety of test conditions reported in literature. Typically, frontal and rear end impacts are of interest and these cause bending, axial as well as torsional loading on the cervical spine. A computational model can be expected to validate against multiple boundary conditions and initial conditions. Therefore, validation of a computational model (THUMS) in varying test conditions is of significance. Thus the objective of the current work is to independently investigate the fidelity of the neck model of THUMS under varying impact conditions.

From the initial seating position the Thums model has been modified to match the initial position in the tests. The impact test conditions used in the experiments have been then recreated in PAMCRASH™ and simulations have been carried out to validate the neck model. The models and the material properties have then been iterated and the performance of the Thums model has been investigated vis-à-vis the experimental results.