Data-Driven Constitutive Model for the Inelastic Response of Metals: Application to 316H Steel
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TECHNICAL ARTICLE
Data‑Driven Constitutive Model for the Inelastic Response of Metals: Application to 316H Steel Aaron E. Tallman1 · M. Arul Kumar1 · Andrew Castillo2 · Wei Wen1 · Laurent Capolungo1 · Carlos N. Tomé1 Received: 24 April 2020 / Accepted: 14 August 2020 © This is a U.S. government work and its text is not subject to copyright protection in the United States; however, its text may be subject to foreign copyright protection 2020
Abstract Predictions of the mechanical response of structural elements are conditioned by the accuracy of constitutive models used at the engineering length-scale. In this regard, a prospect of mechanistic crystal-plasticity-based constitutive models is that they could be used for extrapolation beyond regimes in which they are calibrated. However, their use for assessing the performance of a component is computationally onerous. To address this limitation, a new approach is proposed whereby a surrogate constitutive model (SM) of the inelastic response of 316H steel is derived from a mechanistic crystal plasticity-based polycrystal model tracking the evolution of dislocation densities on all slip systems. The latter is used to generate a database of the expected plastic response and dislocation content evolution associated with several instances of creep loading. From the database, a SM is developed. It relies on the use of orthogonal polynomial regression to describe the evolution of the dislocation content. The SM is then validated against predictions of the dead load creep response given by the polycrystal model across a range of temperatures and stresses. When the SM is used to predict the response of 316H during complex non monotonic loading, extrapolating to new loading conditions, it is found that predictions compare particularly well against those from the physics-based polycrystal model. Keywords Crystal plasticity · Reduced order modeling · Creep · Surrogate modeling
Introduction Structural design and certification of metallic components subjected to extreme environments (e.g., high stress, temperature, irradiation) necessarily relies on predictions of the evolution of stresses, elastic strains and inelastic strains during service. This is usually achieved via the use of finite element (FE)-based mechanical and thermal solvers in which the elastic and inelastic response of the polycrystalline metal is described by a constitutive model [1–6]. Ideally, this constitutive model should predict not only the monotonic response of the medium, but also its response under complex loading conditions (e.g., cycling loading, creep fatigue) over a wide range of imposed stresses, strain rates and * Aaron E. Tallman [email protected] 1
Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, USA
George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
2
temperatures. In practice, multiple deformation mechanisms can simultaneously contribute to the inelastic response of metals [7–11]. For examp
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