3331. Prediction of Fracture Damage in and Reliability Based Design Optimization of Composite Structures

Paper

Abstract

A simplified composite analytical life prediction procedure (SAPGEN) is developed for naval joint design that will perform: material constituent analysis (MCA), material uncertainty analysis (MUA), fracture damage, and the percent contribution of each material constituent to failure mechanisms. SAPGEN has the ability to predict: 1) constituent/ply mechanical properties, 2) property degradation, 3) damage modes and mechanisms, 4) failure modes and mechanisms, 5) percent damages due to fourteen specified failure criteria and, 6) the durability/reliability of a composite joint/structure. The progressive failure analysis (PFA) methodology imbedded within SAPGEN utilizes finite element analyses (FEA) and iteratively updates material properties due to the existing loading conditions. The applied load (force, temperature, pressure, etc.) or time is iteratively increased, permitting damage tracking throughout the structure for many loading scenarios. SAPGEN predicts failure mechanisms relevant to composite structures, such as delamination, with simplified finite element models. As a demonstration, SAPGEN was used to determine damage modes within a typical naval joint and compared to test results and current detailed analytical methods.