Abstract
The Twice-Yield method is an elastic-plastic finite element analysis (FEA) pioneered by Professor Arturs Kalnins at Lehigh University which approximates the stabilized cyclic response that would otherwise be obtained from a cycle-by-cycle elastic-plastic FEA. The Twice-Yield method is used to evaluate the load range conditions which occur between any two load states from the stabilized cyclic structural response. The rigorous implementation of the Twice-Yield method requires special handling of material properties. In particular, the method requires the average of the properties corresponding to the two load states. This paper documents a detailed technical basis of the Twice-Yield method’s implementation in Abaqus including the special handling of material properties. An assessment of the Twice-Yield method is performed based on analyzing a thermally shocked stepped pipe. Included in the assessment are comparisons of the cycle-by-cycle elastic-plastic FEA results and the Twice-Yield method elastic-plastic FEA results. The comparisons show the efficacy of the Twice-Yield method as a viable cyclic elastic-plastic analysis method.
