Element Simulation Of Residual Stress Research Articles

Three-dimensional finite element simulation of residual stresses in circumferential welds of steel pipe including pipe diameter effects

In circumferential welding of a pipe component, it is often considered that axisymmetric model can provide a reasonable prediction of the residual stress distributions. However, in general, the axisymmetric model cannot reproduce the traveling arc along circumferential welds and rapid change of residual stresses that can be observed in the overlapping region. Moreover, it tends to overestimate the hoop residual stresses in circumferential welds. Therefore, three-dimensional finite element (FE) model is essential for the accurate simulation of circumferential welding which can incorporate the three-dimensional effects. This paper presents the three-dimensional FE simulation of circumferential butt welding of a steel pipe. The thermo-mechanical model used as well as the simulation methodology is detailed, and the results are discussed. In addition, parametric studies with inside radius to wall thickness ratio ranging from 10.0 to 100.0 have been presented to investigate the effects of pipe diameter on residual stresses. Axial and hoop residual stresses are plotted for the considered range of pipe diameters, and the differences are discussed.

3-D Finite Element Simulation of Welding Residual Stresses in Pipe-Flange Joints: Effect of Welding Parameters

This paper presents results of detailed three-dimensional finite element simulation of residual stress distribution in welded Pipe-Flange Joints with emphasis on the effect of welding parameters and geometrical size of the model. Single-pass Metal Inert Gas welding with single “V” Butt-weld geometry is used in the study. The effect of two basic welding parameters including welding current and speed and two geometrical parameters i.e. pipe diameter and wall-thickness are examined. For both welding current and welding speed, three sets of parameters comprising of low, medium and high values are used. To analyze the effect of each parameter explicitly only one parameter is changed at one time. In most of the cases 100 mm nominal pipe diameter is used. A FE Model for 200 mm nominal pipe diameter is also analyzed to determine the effect of pipe diameter.

Residual stresses in spot welded new generation aluminium alloys Part B – finite element simulation of residual stresses in a spot weld in 5754 aluminium alloy

An incremental thermo-electrical-mechanical coupled finite element model has been developed for predicting the residual stress field in a 5754 aluminium alloy spot welded joint. The complete spot welding process, including squeezing, welding, holding and cooling cycles, as well as the temperature and stress histories during those cycles in the welded joint have been investigated. All the required thermo-physical and thermo-mechanical properties used were experimentally measured. The results show that tensile residual stress predominates the spot nugget area. The highest tensile residual stress, with a value close to the material's yield strength, occurs around the centre of the nugget. The residual stress value decreases slightly towards the edge of the spot nugget.

Finite Element Simulation of Residual Stresses in Epitaxial Layers

A nonlinear finite element approach presented here is based on the constitutive equations for anisotropic hyperelastic materials. By digital image processing the elastic incompatibilities (lattice mismatch) are extracted from the HRTEM image of GaN epilayer. Such obtained tensorial field of dislocation distribution is used next as the input data to the FE code. This approach is developed to study the stress distribution associated with lattice defects in highly mismatched heterostructures applied as buffer layers for the optically active structures.