Innovative Composite/Metallic Joint Concepts and Analysis Techniques

Proposed are two innovations for improved structural analysis and weight savings of composite/metallic joint concepts. First is the development of new structural analysis capabilities and second is the design and analysis of two novel hybrid joint concepts that minimize composite to metallic thermal mismatch. New structural analysis capabilities include two complimentary approaches to damage tolerance. First, a non-FEA fracture mechanics Virtual Crack Closure Technique (VCCT) used to predict crack growth. Second, a continuum based progressive damage model, similar to recent ABAQUS “cohesive” elements, implemented with micromechanics rather than FEA. These analysis methods will be included in the commercial rapid design/analysis/sizing tool called HyperSizer®, resulting in an innovative capability available no where else. The two innovative hybrid joint concepts are a bi-layered strip and slotted fiber metal laminate (FML), both reducing joint residual thermal stresses. The focus of this research is to quantify potential weight savings while ensuring structural integrity through rapid analysis and sizing. To compare relative merit in joint trade studies, a Joint Performance Metric (JPM) will be established for comparing joint strength. In Phase II test articles will be fabricated and tested and results used for analysis code validation and reliability analysis.