Stiffness degradation of composite skin fields due to strength and buckling onset

Suitable and fast calculation methods with sufficient accuracy are required to optimise large composite structures. The present paper introduces a progressive stiffness degradation analysis (PSDA), which computes skin buckling onset and strength failure initiation of skin fields separated by stiffeners, as well as the subsequent damage propagation using closed form solutions. This constitutes a simplified, but much faster approach compared to state of the art progressive failure analyses, which incorporate finite element simulations. Therefore, the computational effort can be reduced. This paper illustrates the process of the PSDA and then verifies this simplified approach by means of one example.