Anisotropic Multiscale Modelling in SAE-AISI 1524 Gas Tungsten Arc Welded Joints

Edison A Bonifaz,Ikumu Watanabe

doi:10.3390/cryst11030245

Edison A Bonifaz, Ikumu Watanabe

Open Access

https://doi.org/10.3390/cryst11030245

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Abstract

A transient non-linear multiscale finite element heat flow-mechanical model to determine micro residual stresses (type III) and micro plastic strains in SAE-AISI 1524 gas tungsten arc welded joints is developed. To include anisotropy by preferred crystallographic orientation or texture, the global domain was decomposed into small subdomains based on the concept of representative volume elements (RVEs). A three-dimensional numerical procedure was developed by using the coupling DREAM.3D-ABAQUS. The macro scale temperature gradient information as prescribed driven (load) boundary conditions was used to calculate the meso thermal cycles, and the meso scale temperature gradient information was used to calculate the micro thermal cycles needed in the subsequent mechanical analysis. Anisotropy was included by randomly entering in each grain of the RVE specimen either the maximum Young’s modulus (Emax) in the stiffest direction <111>, or the minimum Young’s modulus (Emin) in the least stiff direction <100>. Under this assumption, the averaging of the grain orientations over all grains in the textured polycrystal with greater number of grains ocurred, and the strength was diluted by the spread of orientations present. Higher Mises stresses evolved in the sample with coarse grain size (16 µm), which indicates that the strong dependence of residual micro stresses on grain size was reversed. The influence of the grain size on the response of the aggregates is clearly observed.

Highlights

In recent investigations [26,27], dendritic morphology evolution, micro residual stresses, and dislocation evolution have been integrated into a fluid-thermal-metallurgical-mechanical multiscale approach
Material microstructures are available in many different shapes and sizes and their features of interest have different dimensionalities
By abstracting the materials interpretation of the features and focusing only on how the feature is described digitally, the code DREAM.3D has been able to constitute a general, unified structure for digital data that assumes no previous knowledge of material class or length-scale [18]

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The characterization of mechanical and physical properties, on nano-, micro-, and meso scales is important for assessing other characteristics of materials such as yield strength, elastic–plastic deformation, time-dependent creep, residual stresses, fatigue, and fracture toughness. In order to calculate macro and micro variables of stress and strain, the finite element mesh of the polycrystal is loaded by prescribed driven (load) boundary conditions It better understood if the features of the material microstructure are considered in the modeling framework [9,17,18]. The novelty of the present research is the development and application of a transient non-linear multiscale finite element model in the determination of micro residual stresses (type III) and micro plastic strains in gas tungsten arc welded joints. On the sublevel scales, the evolution of the microstructure can be predicted with the phase field method by inputting the calculated numerical thermal results as the initial boundary conditions

The Multiscale Finite Element Model

Two grains generated with thethe code

Results and Discussion

Conclusions

Anisotropy included in in thethe