Determination of in-plane elastic constants of angle ply laminates from tensile measurements

This paper presents a new method to completely characterise the in-plane elastic properties of an important type of angle ply laminates using only unidirectional tests. The angle ply laminates having the same number of identical plies are considered. Some new results for orthotropic laminates are found using this technique, namely, the conditions of existence of a particular direction in which there is no shear extension coupling. The laminates are subjected to three tensile tests: two in the orthotropic axes and the third one in a particular direction. The results allow a complete semiexperimental characterisation of the angle ply laminate, which do not need a priori knowledge of the elastic properties of the constitutive layer. Comparisons are made between numerical predictions and experimental results. Finally, the computational results were compared to the experimental results, verifying the capability of the method in order to predict the in- plane elastic properties of composite laminates.