Development of a Dynamic Biomechanical Model for Load Carriage: Phase 4, Parts A and B: Development of a Dynamic Biomechanical Model Version 2 of Human Load Carriage

The purpose of this DRDC dynamic biomechanical model research program is to improve the understanding of human load carriage capabilities and to understand the effects of load carriage design features on human health and mobility. This research is directed at creating a method of determining several of the biomechanical factors to be used as inputs to the Load Conditions Limit model as described in DRDC report# W7711-0-7632-01 entitled "Proposed Long Range Plan for a Research and Development Program of Dynamic Load Carriage Modeling." In the current study, a 3D solid model was split into an upper and lower torso coupled with a rigid join located at the location of the spine at the L3/L2 height. Acceleration histories of subjects wearing packs were previously recorded during human trials. Acceleration of a person was numerically integrated and used to drive the motion of the Dynamic Biomechanical Model (DBM) torso. Torso accelerations for a wide range of activities were recorded and can be used to drive these models, creating an excellent data base for many human and pack motions for current and future modeling of human motions. This technique of capturing and generating motions is applicable to many situations where an envelope of human motion and body accelerations needs to be tested to ensure equipment does not cause excessive dynamic loading on the soldier. Piecewise linear dynamic, static and creep material response models were developed for typical backpack materials. In addition, a piecewise linear model of the dynamic stress strain response for the Clothe the Soldier shoulder strap assembly was developed. The model estimates reaction forces and moments on the lumbar spine and the total shoulder reaction force. The model also calculates the distribution of force to the upper and lower torso and the total contact force.
Text in English; abstract in French and English. The original document contains color images.