Failure Analysis of Composite Multi-Stringer Panels Using Simplified Models

The postbuckling response and failure of multi-stringer panels is analyzed using finite element models with three levels of approximation. The first model is based on a relatively coarse mesh to capture the global postbuckling response of a multi-stringer panel. The second model can predict the nonlinear response as well as the debonding and crippling failure mechanisms in a Single Stringer Compression Specimen (SSCS). The third model consists of a simplified version of the SSCS that is designed to minimize the computational effort. The simplified model is well-suited to perform sensitivity analyses for studying the phenomena that lead to structural collapse. In particular, the simplified model is used to obtain a deeper understanding of the role played by geometric and material modeling parameters such as mesh size and interlaminar strength. Finally, a global/local damage analysis method is proposed in which a detailed local model is used to scan the global model and identify the locations that are most critical for damage tolerance.