Long and Short Radius Elbow Experiments and Evaluation of Advanced Constitutive Models to Simulate the Responses

Low-cycle fatigue (LCF) and strain ratcheting responses of long and short radius elbows are studied experimentally and analytically. Elbow piping components are widely used in piping systems, however, the prediction of their low-cycle fatigue and ratcheting responses remain a challenge. Hence, a systematic set of short and long radius elbow LCF responses are developed by prescribing displacement-controlled loading cycles with or without internal pressure. A setup comprised of four LVDTs was utilized to measure diameter change during cyclic loading. In order to evaluate the accuracy of the strain gage data, strains are also acquired using the digital image correlation (DIC) technique. Recorded fatigue responses are analyzed in understanding the differences in LCF lives between the long and short radius elbows. The Chaboche nonlinear kinematic hardening constitutive model in ANSYS and a modified version of this model are evaluated for their simulation capability against the recorded elbow responses. The experimental and finite element simulation responses are presented in this article.Copyright © 2015 by ASME