MCML partners with AFRL to study CAI response of composites with enhanced interfaces – 09/04/2019
Title: Modeling Compression-After-Impact Response of Aerospace Composites with Enhanced Interfaces
Research Team : MCML
Source of Support : Air Force Research Laboratory
CAI strength of composites is a very important design limiter in aerospace structures. Even moderate to low energy impact events induce damage in the composite structure, and significantly alter the residual compressive strength and failure response. Since the residual compressive strength is driven by local and global instability phenomena, assessment of the extent and type of damage induced by the impact event and the ability to predict failure in the presence of impact-induced damage is critical to understand and make design, certification, maintenance and asset utilization decisions. Interlaminar strengthening mechanisms (e.g., z-pinning, stitching, needling, tufting) that limit delaminations show significant promise in enhancing CAI strength. Noting the well-known adverse effects of interlaminar enhancements on in-plane properties, it is critical to gain the understanding of how composite structures respond in the presence of in-plane/out-of-plane property trade-off.
This project will focus on carbon fiber/epoxy composites with through-thickness reinforcements by z-pinning and stitching techniques. The PDA model will be experimentally validated and exercised to investigate compression failure in composite specimens with through-thickness reinforcements and structural panels with damage arrestment features. The analysis of through-thickness reinforced configurations will elucidate the primary failure mechanisms by which the reinforcements affect the CAI performance, and offer solutions using parametric analyses to improve performance.