Composite Laminate Design for Improved Open-Hole Compression Strength using Non-Standard Ply Angles and Customized Stacking Sequences Characterized by [D] Matrix

Abstract

The conventional design of composite laminates underutilizes the large design space available due to stacking sequences and ply angles. This paper studies the use of non-standard ply angles and customized stacking sequences by placing higher-angle plies on the surface for reduced ply thickness and increased open-hole compression strength. Tests show non-standard angle designs at matched in-plane stiffness improve failure strength as compared to standard angle wing-skin laminates when subject to a small load misalignment. Customized stacking sequences improve the strength of both standard and non-standard angle designs, the improvement of which linearly decreases by having the lower ply angle on the surface. The results match predictions derived from the [D] matrix.