Abstract: An analysis of the tensile strength of [0/90]5, C45/ - 45]5, and π/4 laminates with a hole of various finite width and the hole diameter is presented. It is found that, the tensile strength of laminates with a hole relates to not only material property, geometry size of sample, but also ply condition. A strength calculate formulation and a method of modification is also given to allow for the edge-effect of the general symmetrical π/4 laminates with a hole. This is an empirical approach based on the result of experiments. This approach is different compared to former approaches based on model for strength of materials or fracture mechanics. It is a approach based on model for mechanics of composite materials, which considered ply-condition of composite materials.

Key words: laminates with a hole, laminates of finite width, edge-effect, tensile strength, composite materials