Determination of Optimized Biaxial Cruciform Specimens of Mild Steels, SS 316L, and Aluminum Alloys

A methodology is described for obtaining optimum biaxial cruciform specimen designs by combining equibiaxial tension test data with finite element analysis (FEA) in conjunction with the application of an appropriate optimization strategy. This approach is applied for developing optimum specimen designs for an ASTM A1008 steel, a SS 316L, and an AA 6xxx-T4 alloy. This methodology requires in sequence the (a) selection of an appropriate initial biaxial specimen design and development of an equivalent, verified FEA model, b) optimization of the verified FEA models, (c) fabrication of cruciform specimens according to the optimized dimensions and testing under appropriate loading conditions, and (d) simulating the validation test with an equivalent FEA model with boundary conditions obtained from the tests. This study shows that such a combined “test-FEA-optimization” approach can be successfully applied to develop optimum cruciform specimen designs for advanced lightweighting materials.