Cyclic Plasticity and Low Cycle Fatigue of an AISI 316L Stainless Steel: Experimental Evaluation of Material Parameters for Durability Design

Abstract

AISI 316L stainless steels are widely employed in applications where durability is crucial. For this reason, an accurate prediction of its behaviour is of paramount importance. In this work, the spotlight is on the cyclic response and low-cycle fatigue performance of this material, at room temperature. Particularly, the first aim of this work is to experimentally test this material and use the results as input to calibrate the parameters involved in a kinematic and isotropic nonlinear plasticity model (Chaboche and Voce). This procedure is conducted through a newly developed calibration procedure to minimise the parameter estimates errors. Experimental data are eventually used also to estimate the strain–life curve, namely the Manson–Coffin curve representing the 50% failure probability and, afterwards, the design strain–life curves (at 5% failure probability) obtained by four statistical methods (i.e., deterministic, “Equivalent Prediction Interval”, univariate tolerance interval, Owen’s tolerance interval for regression). Besides the characterisation of the AISI 316L stainless steel, the statistical methodology presented in this work appears to be an efficient tool for engineers dealing with durability problems as it allows one to select fatigue strength curves at various failure probabilities depending on the sought safety level.

Strain‐controlled fatigue loading of an additively manufactured AISI 316L steel: Cyclic plasticity model and strain–life curve with a comparison to the wrought material

“…Finally, for the sake of comparison with the “wrought” variant of this steel, a perfectly comparable dataset obtained in a recent study by the authors was considered, using identical sample geometry and testing conditions 34 . Figure 2A,B shows the typical microstructure of additively manufactured specimens compared with the wrought material.…”

“…Parameters of the kinematic hardening model were calibrated by adopting the same procedure used in Pelegatti et al, 34 which had given satisfying results. The principal steps are outlined.…”

“…The evolution of the experimental stress amplitudes up to forms the basis for calibrating the isotropic hardening model. As described in a previous work, 34 the procedure to estimate the isotropic model parameters requires that the kinematic hardening contribution (computed with the parameters estimated previously) is removed from the experimental cyclic stress response. Essentially, the fitting procedure explained below is based not only on the experimental data but also on the simulation process.…”

Strain-Controlled Fatigue Behavior and Microevolution of 316L Stainless Steel under Cyclic Shear Path

“…Branco et al [ 22 ] developed the total strain energy density method to evaluate the fatigue life of notched specimens subjected to multiaxial loads, and the fatigue master curve can be efficiently generated from only two uniaxial strain-controlled tests, and a set of numerical simulations performed via single-element elastic-plastic models. Pelegatti et al [ 23 ] established a robust procedure for durability design to estimate the strain–life curve, which was an effective way to deal with durability problems. Li et al [ 24 ] proposed an energy-based model to predict the creep-fatigue, combined with high-low cyclic loading life.…”

Statistical Estimation of Resistance to Cyclic Deformation of Structural Steels and Aluminum Alloy

“…In recent years, a considerable number of methods of probabilistic analysis of low cycle properties have been investigated [3][4][5][6][7][8]. Cyclic stress-strain curves, the same as uniaxial stress-strain curves, are known to be very sensitive to variations in material chemical composition, heat treatment, surface hardening, loading conditions, and other factors.…”