SBIR-STTR Award

Structural laminated composites are used extensively in new aircraft applications. Expensive large test programs are conducted to generate composite strength allowables because existing analytical methods are not accurate. These existing large test programs have never comprehensively reviewed together.NSE Composites Stress Services (NSE) and Stanford University are teamed to accurately characterize laminated composites strength behavior. NSE will conduct a comprehensive evaluation of the existing test database and will reduce the data into empirical characteristic equations. Stanford will analytically predict strength with their existing progressive damage models. The empirical characteristic equations will be used to validate and/or improve the progressive damage models.In Phase I, an empirical characteristic equation will be generated and used to evaluate progressive damage predictions for a selected test configuration over 4 material systems. Phase II will focus on additional test configurations, material systems, and an overall validation of the progressive damage method.

NSE Composites Stress Services (NSE) and University of Dayton Research Institute (UDRI) are teamed to accurately characterize laminated composites strength behavior. NSE will conduct a comprehensive evaluation of existing large government databases of open and filled hole tension tests, and will analytically predict strength with first-ply-failure and progressive damage models. NSE will then derive characteristic equations for failure modes in each material system. UDRI will conduct an in-depth test program to investigate failure progression in open and filled hole, tension and compression coupons. UDRI will also add clamp-up effects to its spline stress analysis model, SVELT. The test data and characteristics equations will be used to validate the analytical models.

Keywords:
COMPOSITES STRENGTH GRAPHITE/EPOXY FAILURE GRAPHITE/BMI ALLOWABLES LAMINATE PROGRESSIVE DAMAGE