Prediction of work-hardening coefficient and exponential by adaptive inverse finite element method for tubular material

A new methodology to determine the tubular material properties based on the common inverse finite element analysis, "Adaptive Inverse Finite Element Method" (AIFEM), is presented in this paper to perform accurate and efficient calculations to obtain the material work-hardening coefficient K and material work-hardening exponential n. This methodology was based on analyzing how different material parameters affect the shape of PH curve when undergoing a tube hydraulic bulge test (THB), and formulating the modified rules and calculations to adaptively adjust and control the material parameters. This methodology can also (1) perform real-time monitoring of the process of THB, (2) compare the differences between the simulated PH curve and the actual PH curve, and (3) draw on the regulations and calculations to adjust the simulated PH curve to become fully intersected with the actual curve, hence obtaining the necessary material parameters by using the adaptive inverse finite element analysis. Through the validation of FEM and experiments, the adaptive inverse finite element analysis has been shown to reduce the calculation time and manpower significantly and to enable more accurate prediction of the material parameters.