Using Nonlinear Kinematic Hardening Material Models for Elastic–Plastic Ratcheting Analysis

Abstract

Applicable design codes for power plant components and pressure vessels demand for a design check against progressive plastic deformation. In the simplest case, this demand is satisfied by compliance with shakedown rules in connection with elastic analyses. The possible noncompliance implicates the requirement of ratcheting analyses on elastic–plastic basis. In this case, criteria are specified on maximum allowable accumulated growth strain without clear guidance on what material models for cyclic plasticity are to be used. This is a considerable gap and a challenge for the practicing computer-aided engineering engineer. As a follow-up to two independent previous papers PVP2013-98150 ASME (Kalnins et al., 2013, “Using the Nonlinear Kinematic Hardening Material Model of Chaboche for Elastic-Plastic Ratcheting Analysis,” ASME Paper No. PVP2013-98150.) and PVP2014-28772 (Weitze and Gilman, 2014, “Additional Guidance for Inelastic Ratcheting Analysis Using the Chaboche Model,” ASME Paper No. PVP2014-28772.), it is the aim of this paper to close this gap by giving further detailed recommendation on the appropriate application of the nonlinear kinematic material model of Chaboche on an engineering scale and based on implementations already available within commercial finite element codes such as ANSYS® and ABAQUS®. Consistency of temperature-dependent runs in ANSYS® and ABAQUS® is to be checked. All three papers together constitute a comprehensive guideline for elastoplastic ratcheting analysis. The following issues are examined and/or referenced: (1) application of monotonic or cyclic material data for ratcheting analysis based on the Chaboche material model, (2) discussion of using monotonic and cyclic data for assessment of the (nonstabilized) cyclic deformation behavior, (3) number of backstress terms to be applied for consistent ratcheting results, (4) consideration of the temperature dependency (TD) of the relevant material parameters, (5) consistency of temperature-dependent runs in ANSYS® and ABAQUS®, (6) identification of material parameters dependent on the number of backstress terms, (7) identification of material data for different types of material (carbon steel, austenitic stainless steel) including the appropriate determination of the elastic limit, (8) quantification of conservatism of simple elastic-perfectly plastic (EPP) behavior, (9) application of engineering versus true stress–strain data, (10) visual checks of data input consistency, and (11) appropriate type of allowable accumulated growth strain. This way, a more accurate inelastic analysis methodology for direct practical application to real world examples in the framework of the design code conforming elastoplastic ratcheting check is proposed.

Effect of microstructural constituents and morphological characteristics on low cycle fatigue behaviour of inter-critically annealed 20MnMoNi55 steel

“…The detailed calibration procedures for determining a set of Chaboche kinematic hardening parameters (C 1 –γ 1 , C 2 –γ 2 and C 3 –γ 3 ) were suggested in the literature. 48 Table 3 shows the Chaboche material parameters for different heat-treated samples containing 30%, 35% and 68% martensite, respectively, and thereby observed that the prediction of a cyclic stress–strain curve with those Chaboche parameters exactly matches with the cyclic deformation behaviour of constituent phases as shown in Figure 10.…”

Study on forming and laying process of high strength pipeline steel

“…Rudolph et al [6] used ABAQUS finite element analysis software to analyze the constitutive model of metallic materials.In this paper, the unidirectional tensile test and tensile-compression test of the round bar intercepted in X80 sheet are carried out, and the basic mechanical parameters of the material are obtained.The ABAQUS finite element analysis software was used to establish the same simulation scheme as the experiment. The kinematic hardening model of ABAQUS material library and the kinematic hardening model defined by UMAT are used to calculate and compare the stress-strain curves and the experimental curves respectively.The results show that the effect of the kinematic hardening model defined by the UMAT subroutine is in accordance with the experimental results.…”