Based on the application of Laplace's law to compression garments, an equation for predicting garment pressure, incorporating the body circumference, the cross-sectional area of fabric, applied strain (as a function of reduction factor), and its corresponding Young's modulus, is developed. Design procedures are presented to predict garment pressure using the aforementioned parameters for clinical applications. Compression garments have been widely used in treating burning scars. Fabricating a compression garment with a required pressure is important in the healing process. A systematic and scientific design method can enable the occupational therapist and compression garments' manufacturer to custom-make a compression garment with a specific pressure. The objectives of this study are 1) to develop a pressure prediction model incorporating different design factors to estimate the pressure exerted by the compression garments before fabrication; and 2) to propose more design procedures in clinical applications. Three kinds of fabrics cut at different bias angles were tested under uniaxial tension, as were samples made in a double-layered structure. Sets of nonlinear force-extension data were obtained for calculating the predicted pressure. Using the value at 0° bias angle as reference, the Young's modulus can vary by as much as 29% for fabric type P11117, 43% for fabric type PN2170, and even 360% for fabric type AP85120 at a reduction factor of 20%. When comparing the predicted pressure calculated from the single-layered and double-layered fabrics, the double-layered construction provides a larger range of target pressure at a particular strain. The anisotropic and nonlinear behaviors of the fabrics have thus been determined. Compression garments can be methodically designed by the proposed analytical pressure prediction model.

A new constitutive equation is developed to model the flow stress on a metal surface undergone high speed impacts that result in strain hardening. The new equation is based on the Johnson-Cook model and has considered the effects of strain, strain rate, grain refinement, twin formation and twin spacing. Two mechanisms for the strain hardening are proposed: Grain refinement or twin formation, depending on the strain rate. At low strain rate, the Hall-Petch relation is obeyed, while at high strain rate, the flow stress is controlled by the formation of deformation twins. The theoretical estimation of flow stress agrees well with experimental data for stainless steel 304. According to the new model, the flow stress can be as high as 1.46 GPa at a strain rate of 10 5 /s.