Characterization of Constitutive Behavior of Satin-weave Fabric Composite

As the use of woven fabric composites increases, understanding their elastic behavior is essential. For this study, an experimental approach was undertaken to determine the elastic properties of a woven fabric composite, with a focus on determining stiffness coupling terms that are often neglected in analytical and FEA models. Specimens were fabricated with a 5-harness satin-weave carbon-epoxy composite and were subjected to three loading conditions: tension, bending, and torsion. The approach taken to calculate the stiffness (or compliance) matrix terms is presented, along with symmetry properties that provide some relationships between these terms. The results indicate that the minor coupling terms are difficult to quantify due to the small strains that need to be measured. The results indicate that the minor coupling terms are very sensitive to fiber misalignment. Careful fiber alignment along the longitudinal (warp) direction of test coupons gives coupling terms corresponding to that direction which are much less sensitive to the fiber misalignment. The major in-plane and out-of-plane compliance terms were also measured by the tests conducted.