Element Analysis Of Residual Stresses Research Articles

Finite element analysis of residual stresses in machining

Residual stresses play an important role in the service quality of a component. Therefore, it is essential to predict and control residual stresses on the machined surface and subsurface. The paper is focused on the numerical prediction of residual stresses in the orthogonal cutting process of a mild steel. An advanced approach to model heat transfer phenomena at the tool-chip interface was included in the numerical simulation. The FEM results were compared with some experimental data obtained turning AISI 1045 steel using uncoated WC tool.

Finite Element Analysis of Residual Stress in Diamond/Steel Brazed Joint

In the application of brazed diamond tools, residual stress caused by differences in materials properties is an important factor in obtaining good brazing quality. The residual stress in diamond/steel brazed joint is studied by means of finite element method and Raman spectroscopy in this paper. The comparison between the results from the simulations and the measurements shows that a good agreement has been reached. Tensile stress concentration at the diamond edge near interface was observed. High residual stress concentration may cause cracks in diamond. Actually, cracks in diamond caused by brazing residual stress after were observed. The stress concentration of the joint must be reduced to obtain good brazed joint. The change of brazing atmosphere or to adopt the soft brazing alloy will reduce the stress concentration.

Finite element analysis of residual stress and interlayer in hard coating/interlayer/soft substrate system during nanoindentation

The mechanical properties of thin films are frequently evaluated using nanoindentation. The finite element method (FEM) is very effective for investigating the stress and strain fields of the film–substrate system during nanoindentation. However, the role of residual stress and the thin interlayer between the film and substrate is not well known, especially when the hard coating/interlayer/soft substrate are considered together. In this work, the FEM is used to investigate the load-displacement behavior of the hardness of the hard coating/interlayer/soft substrate system. The load–displacement process is simulated, and the effects of different residual stresses and interlayer thicknesses are discussed.

Finite Element Analysis of Residual Stress and Distortion in Laser Welded Stainless Plate

Article Finite Element Analysis of Residual Stress and Distortion in Laser Welded Stainless Plate was published on December 1, 2007 in the journal Journal for Manufacturing Science and Production (volume 8, issue 2-4).

Finite Element Analysis of Residual Stress and Distortion in Laser Welded Stainless Plate

Article Finite Element Analysis of Residual Stress and Distortion in Laser Welded Stainless Plate was published on December 1, 2007 in the journal Journal of the Mechanical Behavior of Materials (volume 18, issue 5-6).

05/02500 Finite element analysis of residual stresses in a letter-box excavation repair weld for Chapelcross Power Station

05/02500 Finite element analysis of residual stresses in a letter-box excavation repair weld for Chapelcross Power Station

A finite element analysis of residual stress at the unloaded stage of the indentation of an elastic-work hardening layered half-space by a rigid sphere

Residual stress distributions of an elastic plastic contact problem in elastic-work hardening layered half-space indented and removed by a rigid sphere was solved numerically using the finite element method. The case of a surface layer stiffer than the substrate is considered, and general solutions for the upper surface stresses of the layer, the interface stresses between the layer, the substrate, and along the symmetry axis are presented for a relatively thin elastic layer. Crack initiation and decohesion of the layer was also discussed with reference to residual stress distributions.

Finite element analysis of residual stresses in a letter-box excavation repair weld for Chapelcross Power Station

A routine inspection on the heat exchanger 6 boiler in Chapelcross Nuclear Power Station revealed the existence of a crack in the bottom dome of the boiler. A ‘letter-box’ repair procedure was developed to repair the damage and justify the return to service of the boiler. Due to the location of the repair, it was undesirable to conduct post weld heat treatment (PWHT) because this could result in damage to neighbouring components. A full residual stress programme was conducted in order to justify a non-PWHT repair to the boiler using a temper bead technique on a boiler shell section of up to 44 mm. This paper describes the work conducted during the project and subsequently regarding residual stresses in letterbox excavation repairs.

Finite element analysis of residual stress in plasma-sprayed ceramic coatings

AbstractA numerical study was carried out by finite element analysis (FEA) for the calculation of absolute values and through-thickness variation of residual stress originating in thermal spray coa...

Finite element analysis of residual stress in plasma-sprayed ceramic coatings

A numerical study was carried out by finite element analysis (FEA) for the calculation of absolute values and through-thickness variation of residual stress originating in thermal spray coatings. The investigated deposit was an air plasma sprayed alumina coating sprayed on a carbon steel substrate previously coated with Ni20Al bond coat. Results show compressive residual in-plane stresses with linear through-thickness variation and tensile normal and shear stresses having a peak at the coating-substrate interface. The influence of deposition temperature on residual stress was also investigated. The experimental validation of the FEA model was carried out using a high-speed hole drilling technique, suitably adapted for the analysis of a multimaterial structure through FEA calculation of the required calibration coefficients. A very good agreement between simulated and measured stresses was obtained, inspite of the adopted simplification hypothesis.

Finite Element Analysis of Residual Stress in NiCrAlY/Yttria-Stabilized Zirconia Coatings by Nanoscale Multi-Layered Deposition

Finite Element Analysis of Residual Stress in NiCrAlY/Yttria-Stabilized Zirconia Coatings by Nanoscale Multi-Layered Deposition

Finite element analysis of residual stress in the welded zone of a high strength steel

The distribution of the residual stress in the weld joint of HQ130 grade high strength steel was investigated by means of finite element method (FEM) using ANSYS software. Welding was carried out using gas shielded arc welding with a heat input of 16 kJ/cm. The FEM analysis on the weld joint reveals that there is a stress gradient around the fusion zone of weld joint. The instantaneous residual stress on the weld surface goes up to 800 ∼ 1000 MPa and it is 500 ∼ 600 MPa, below the weld. The stress gradient near the fusion zone is higher than any other location in the surrounding area. This is attributed as one of the significant reasons for the development of cold cracks at the fusion zone in the high strength steel. In order to avoid such welding cracks, the thermal stress in the weld joint has to be minimized by controlling the weld heat input.

Finite Element Analysis of Residual Stresses in Zirconia Thermal Barrier Coatings on Superalloy

Finite Element Analysis of Residual Stresses in Zirconia Thermal Barrier Coatings on Superalloy

Nonlinear FE analysis of residual stresses induced by dislocations in heterostructures

In this paper the field theory of dislocations is used in the finite element analysis of residual stresses in epitaxial layers. By digital processing of the HRTEM image of a GaAs/ZnTe/CdTe system the tensor maps of dislocation distribution are extracted. Such obtained maps are used as the input data to the finite element code. The mathematical foundations of this code are based on the compatibility equations for lattice distortions. The surface tension induced by misfit dislocations is considered here in terms of a 3D boundary-value problem for stress equilibrium in the interfacial zone. The numerical results show how strongly the surface tension depends on the nonlinear elastic behaviour of the crystal structure.

Finite element analysis of residual stress induced by shot peening process

The aircraft industry has only recently begun to explore possible application of welding as an alternative joining method for the design of future large civil airliner wing. One of the main obstacles, encountered in the past years, to welding application within the aircraft industries were due to failure in the weldments, caused by high tensile residual stresses present in the region of the weld, reducing drastically fatigue strength of welded joints. Improvement in the fatigue life of the welded joint can be obtained if compressive residual stresses are introduced at the weld region. Shot peening is a manufacturing process intended to give aircraft structures the final shape and to introduce a compressive residual state of stress inside the material in order to increase fatigue life. This paper presents the modeling and simulation of the residual stress field resulting from the shot peening process. The results achieved show that a significant decrease of welding induced tensile residual stress magnitude can be obtained. Good agreement between experimental and numerical results was achieved.

Finite Element Analysis of Residual Stresses of Thermal Barrier Coatings

Finite Element Analysis of Residual Stresses of Thermal Barrier Coatings

Effects of Residual Stress on Fracture Strength of Si<SUB>3</SUB>N<SUB>4</SUB>/Stainless Steel Joints With a Cu-Interlayer

The variation in fracture strength of a brazed Si3N4/Cu/steel joint was compared with the change in residual stress as a function of the Cu-interlayer thickness that was used. The higher residual stress and the lower measured fracture strength for the joint, using a 0.1 mm thick Cu-interlayer, were ascribed to the entire dissolution of the Cu-interlayer into the brazing alloy. The finite element analysis of residual stress, which considered the microstructure at the interface region, could explain the fracture behavior for the brazed joints, which is dependent on the thickness of the Cu-interlayer.

A finite element analysis of residual stresses in stretch turning

An analytical method has been proposed in this paper to determine the residual stresses in stretch turning. This is done using the thermal elasto-plastic finite element method to determine the transient temperature distribution, followed by thermal elasto-plastic stress analysis. An attempt to explain the mechanism of stretch turning is made, and the effects of stretch level on residual stresses are also discussed.

Logarithmic Singularity on Thermal or Residual Stress at the Interface Edge Point of Bonded Dissimilar Materials.

It is well known that the stresses become singular at the edge point of the interface between dissimilar materials. The singularity has been reported by Bogy for the isothermal elastostatic case with stress free edges and also with the edge subjected to surface tractions. However the singularity for the thermal stress or the bonding residual stress has not yet been clarified. In this study, we fouud that the logarithmic singularity appears in the thermal or residual stresses at the edge of the interface similar to the isothermal problems subjected to discontinuous surface tractions at the edge point. By the boundary element analysis of residual stress for various combinations of dissimilar materials, it is verified that the logarithmic singularity exists for any combination of materials.

Finite Element Analysis of Residual Stresses in Threaded End Closures

Due to the high stress concentration at the root of the first active thread in threaded end closures of high pressure vessels, yielding may occur in this region during the application of the first pressure cycle or proof testing. This overstraining introduces residual stresses that influence the fatigue performance of the vessel. This paper presents a parametric analysis of threaded end closures using elastic and elasto-plastic finite element solutions. The results are used to discuss the influence of these residuals on the estimated fatigue life when the vessel is subjected to repeated internal pressure. A simple empirical method to allow for the Bauschinger effect of the material is also proposed.