Female Body Armor Fit: Measurement Methods, Software Tools, and Finite-Element Simulation

Abstract

Body armor worn on the torso provides critical protection for warfighters, police officers, and others who require protection from penetrating threats. Good body armor fit provides the best trade-off between comfort and protection. Female warfighters frequently report that body armor vests, plates, and plate carriers do not fit them well, resulting in discomfort, pain, and reduced performance. Prior studies have demonstrated that the differences in the distribution of torso size and shape between men and women account for much of the poor fit that occurs when women use systems originally designed for men, but the development of female-specific systems has not eliminated the issues. This report describes the methods and outcomes of a multi-facetted study addressing female body armor fit and related software and simulation tools. A laboratory study was conducted to develop and apply three-dimensional (3D) surface scanning methods for quantifying torso deformation. Data were gathered in a range of postures using a custom carrier system and plastic surrogate plates designed to present a generic contour not specific to any body armor system. Transparent plates were used in some trials to enable more detailed capture of torso shape in the areas of plate interaction. Statistical modeling of the 3D data from 35 participants demonstrated the complex interactions between torso shape, bra type, and tightness that determine how the soft tissue deforms. In addition to the laboratory work, software applications were developed for use in body shape measurement and modeling. These tools provide state-of-the-art methods for head fitting, quantitative pose change, and multi-pose whole-body template fitting. Using results from the laboratory study, a finite-element simulation framework was developed to use physics-based modeling to predict torso deformation under body armor. Demonstration of the framework showed good agreement between simulation results and the empirical findings. This study laid the groundwork for future empirical and simulation studies aimed at improving the design of body armor systems to provide better comfort and performance for women with a wide range of body sizes and shapes.