The state of muscle contraction has been shown to influence occupant kinematics during low-speed impacts and pre-crash events. Furthermore, changes in occupant posture alter the performance of the implemented safety systems. Finite element human body models with active musculature are useful tools for predicting occupant kinematics in low-speed impacts and pre-crash events. In this dissertation, a small female and an average male model with active musculature were developed and validated. For this development, the Global Human Body Models Consortium simplified models of the small female and average male occupants were used as baseline models.

All the major skeletal muscles in the body were modeled as 1-dimensional beam elements. The hill-type muscle material model was assigned to all muscle parts. Data on the physiological cross-sectional area (PCSA) for each muscle was taken from literature sources for an average male model. For the female model, the PCSA values were mass scaled. A PID controller-based muscle activation strategy was used for calculating muscle activation using joints angles and muscle length as control variables. The contribution of various discrete motions in activating each muscle was quantified through a simulation-based study. The effect of controller parameters, reaction delay, and initial muscle activation was initially studied using an upper extremity model. The results of this study suggested a different set of controller parameters and reaction delays for simulating various conditions based on occupant awareness and muscle condition. The PID-controller parameters for the whole-body models were tuned using the design of experiments.

Both models were validated in the relaxed and braced muscle conditions using experimental data in a frontal and oblique direction from volunteers of the same body habitus as each model. The kinematics and kinetic data from validation simulations were compared with the experimental data. Correlation and Analysis (CORA) was used for performing a quantitative analysis of the results. The results of the validation simulation show good agreement with the experimental data. The differences between active and baseline models without muscle activation (control) were demonstrated to be statistically significant using Wilcoxon signed-rank test at a significance level of alpha – 0.05. Both active models are capable of predicting occupant kinematics in pre-crash braking and low-speed maneuvers in frontal and oblique directions and have the potential to be used in safety system designs.