Development of Noninteraction Material Models With Cyclic Hardening

Abstract

Simulation plays a critical role in the development and evaluation of critical components that are regularly subjected to mechanical loads at elevated temperatures. The cost, applicability, and accuracy of either numerical or analytical simulations are largely dependent on the material model chosen for the application. A noninteraction (NI) model derived from individual elastic, plastic, and creep components is developed in this study. The candidate material under examination for this application is 2.25Cr–1Mo, a low-alloy ferritic steel commonly used in chemical processing, nuclear reactors, pressure vessels, and power generation. Data acquired from prior research over a range of temperatures up to 650 °C are used to calibrate the creep and plastic components described using constitutive models generally native to general-purpose fea. Traditional methods invoked to generate constitutive modeling coefficients employ numerical fittings of hysteresis data, which result in values that are neither repeatable nor display reasonable temperature dependence. By extrapolating simplifications commonly used for reduced-order model approximations, an extension utilizing only the cyclic Ramberg–Osgood (RO) coefficients has been developed. This method is used to identify the nonlinear kinematic hardening (NLKH) constants needed at each temperature. Single-element simulations are conducted to verify the accuracy of the approach. Results are compared with isothermal and nonisothermal literature data.

An integrated unified elasto-viscoplastic fatigue and creep damage model with characterization method for structural analysis of nickel-based high-temperature structure

“…There are two approaches to simulate time-dependent material behavior in the Finite Element (FE) analysis. One is to consider the effects of plastic deformation and creep behavior independently by using independent strain components ( εitalicplastic, εitaliccreep) (Bouchenot et al., 2016, 2018; Cao et al., 2018). Although this method can find material parameters easily from experiments, it has a limitation in accurately reflecting the interaction between creep and plastic deformation under complex loading conditions (Chaboche, 2008; Henshall and Miller, 1990).…”