Response surface analysis of biaxial mechanical properties and elastic parameters for woven fabric composites

This paper describes a self-developed MATLAB program for achieving complex deformation properties and accurate elastic parameters of woven fabrics. Using this program, the response surface analyses of deformation and elastic parameters were conducted to reveal the variation and evolution in stiffness, Poisson’s ratio, and orthotropy of the laminated woven fabric composite under different loading/unloading stages, cycles, stress levels and ratios, which is a further development of our prior work. Results show that elastic parameters and orthotropic characteristics of the material vary noticeably with the loading/unloading stages, cycles, stress levels, and ratios. As higher values are required to model the remarkable warp–weft interaction and large negative strains, Poisson’s ratios in boundary regions with a maximum of 1.0 (loading) or 1.5 (unloading) are outside the bounds normally expected for these parameters. In addition, the proposed method is feasible to evaluate elastic parameters for any stress state, and thereby provides new insights into underlying deformation mechanisms of woven fabric composites.