Development of a Dynamic Biomechanical Model for Load Carriage: Phase V: Development of the Biomechanical Model by Means of the Portable Measurement System

Abstract : Soldier operational performance is impacted by a number of factors including physiological workload, the biomechanical effects of equipment used in the field, demographics and soldier readiness. The specific objectives of the work reported here are to identify components of a load carriage limit (LCL) equation specifically related to the physiological workload and biomechanical effects, and to further the development of a dynamic biomechanical model (DBM) for load carriage. The ultimate goal of this research program is to develop and fully validate an LCL equation, which includes all relevant factors and which can be used to predict the operational effectiveness of soldiers in the field. Data were collected in a previous contract on 10 physically fit male subjects. In the DBM development, a skin layer with appropriate properties was created for the torso model and the modeling of all relevant pack components that form the person-to-pack interface has been completed. Stress analyses, in the equilibrium state, for the skin layer, and the shoulder strap and waist belt contact regions were done. A library of material properties for biological (skin on the back, skin toughened, skin over bone) and pack materials, both individually and in combination, has been compiled. Completion of the DBM will entail validating the motion and stress response of the DBM against existing test data, improving the user interface, and adding an output format that will provide the biomechanical factor for input into the LCL equation.