Finite Element Thermal/Mechanical Analysis of Transmission Laser Microjoining of Titanium and Polyimide

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Ankitkumar P. Dhorajiya ◽  
Mohammed S. Mayeed ◽  
Gregory W. Auner ◽  
Ronald J. Baird ◽  
Golam M. Newaz ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Dissimilar Materials ◽  
Optical Microscope ◽  
Mechanical Analysis ◽  
Maximum Temperature ◽  
Stress Profile ◽  
Residual Stress Profile ◽  
Thermal Mechanical Analysis

Detailed analysis of a residual stress profile due to laser microjoining of two dissimilar biocompatible materials, polyimide (PI) and titanium (Ti), is vital for the long-term application of bio-implants. In this work, a comprehensive three-dimensional (3D) transient model for sequentially coupled thermal/mechanical analysis of transmission laser (laser beam with wavelength of 1100 nm and diameter of 0.2 mm) microjoining of two dissimilar materials has been developed by using the finite element code ABAQUS, along with a moving Gaussian laser heat source. First the model has been used to optimize the laser parameters like laser traveling speed and power to obtain good bonding (burnout temperature of PI>maximum temperature of PI achieved during heating>melting temperature of PI) and a good combination has been found to be 100 mm/min and 3.14 W for a joint-length of 6.5 mm as supported by the experiment. The developed computational model has been observed to generate a bonding zone that is similar in width (0.33 mm) to the bond width of the Ti/PI joint observed experimentally by an optical microscope. The maximum temperatures measured at three locations by thermocouples have also been found to be similar to those observed computationally. After these verifications, the residual stress profile of the laser microjoint (100 mm/min and 3.14 W) has been calculated using the developed model with the system cooling down to room temperature. The residual stress profiles on the PI surface have shown low value near the centerline of the laser travel, increased to higher values at about 165 μm from the centerline symmetrically at both sides, and to the contrary, have shown higher values near the centerline on the Ti surface. Maximum residual stresses on both the Ti and PI surfaces are obtained at the end of laser travel, and are in the orders of the yield stresses of the respective materials. It has been explained that the patterned accumulation of residual stresses is due to the thermal expansion and contraction mismatches between the dissimilar materials at the opposite sides of the bond along with the melting and softening of PI during the joining process.

scholarly journals On the Accuracy of Finite Element Models Predicting Residual Stresses in Quenched Stainless Steel

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1308 ◽  
Author(s):  
Israel Medina-Juárez ◽  
Jeferson Araujo de Oliveira ◽  
Richard J. Moat ◽  
Francisco Alfredo García-Pastor
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Contour Method ◽  
Stress Profile ◽  
304L Stainless Steel ◽  
Fem Model ◽  
Residual Stress Profile ◽  
Industry Applications

Prediction of residual stress profiles after quenching is important for a range of industry applications. Finite element method (FEM) models have the capability of simulate the cooling and stress evolution during quenching; however, they are very dependent on the heat transfer coefficient (HTC) imposed on the surface. In this paper, an analysis of the HTC effect on the accuracy of the residual stress profile after quenching a 304L stainless steel Jominy sample was conducted. The FEM model was validated in its thermal accuracy using thermocouples and the residual stress profile was measured using the contour method. The results show that a thermally validated FEM model may yield results which overestimate the tensile residual stress and underestimates the compressive residual stress maxima while accurately calculating the maxima positions from the quenched edge. The FEM model accuracy was not improved by modifying the HTC or by using a different thermal expansion coefficient. The results are discussed in terms of the effect of plasticity due to twinning in the residual stresses calculated by the FEM model.

On the convergence of solid meshes for the prediction of part distortions due to residual stresses

2019 ◽  
Vol 233 (17) ◽  
pp. 6209-6217
Author(s):  
JCR Albino ◽  
LA Gonçalves Junior ◽  
VE Beal
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Stable Condition ◽  
Production Costs ◽  
Raw Material ◽  
Rolled Plate ◽  
Internal Stresses ◽  
Stress Profile ◽  
Residual Stress Profile

Residual stresses in rolled plates, used as raw material for the fabrication of aircraft components, arise from manufacturing processes such as rolling, casting, quenching, stretching, and thermal treatments. After each process, the rolled plate has a geometrically stable condition but with internal stresses. However, during part machining an unbalance in the distribution of residual stresses occurs, in special for aircraft components, due to the large amount of material removal throughout the process. This condition of instability leads to component distortions so that any corrective action affects the manufacturing lead-time and production costs. Part distortions are usually predicted by finite element analyses with linear tetrahedral meshes in which the residual stress profiles are applied as a constant value element-wise. In this work, both linear and quadratic solid meshes are employed to address this problem. For this purpose, a Python-based routine is implemented to apply the residual stress profile at the integration points of the elements. Then, finite element simulations of simple geometric configurations (plates and beams) under theoretical and real residual stress distributions are carried out. Performance and effectiveness of two different meshes—tetrahedral and hexahedral (brick-type)—are checked through comparison with results presented by classical plate and beam theories. A general good correlation for the deflections predicted by them is reached.

scholarly journals Cross-Sectional Mapping of Residual Stresses by Measuring the Surface Contour After a Cut

2000 ◽  
Vol 123 (2) ◽  
pp. 162-168 ◽  
Author(s):  
M. B. Prime
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Measurement ◽  
Superposition Principle ◽  
New Method ◽  
Contour Method ◽  
Stress Profile ◽  
Relaxation Methods ◽  
Cross Sectional ◽  
Residual Stress Profile

A powerful new method for residual stress measurement is presented. A part is cut in two, and the contour, or profile, of the resulting new surface is measured to determine the displacements caused by release of the residual stresses. Analytically, for example using a finite element model, the opposite of the measured contour is applied to the surface as a displacement boundary condition. By Bueckner’s superposition principle, this calculation gives the original residual stresses normal to the plane of the cut. This “contour method” is more powerful than other relaxation methods because it can determine an arbitrary cross-sectional area map of residual stress, yet more simple because the stresses can be determined directly from the data without a tedious inversion technique. The new method is verified with a numerical simulation, then experimentally validated on a steel beam with a known residual stress profile.

Study of Effect of Repetition Rate on Laser Shock Peening Using Finite Element Modeling

2020 ◽  
Author(s):  
Sai Kosaraju ◽  
Xin Zhao
Keyword(s):  
Shock Wave ◽  
Residual Stress ◽  
Finite Element ◽  
Shock Waves ◽  
Repetition Rate ◽  
High Repetition Rate ◽  
Stress Profile ◽  
Surface Residual Stress ◽  
Residual Stress Profile ◽  
High Repetition

Abstract A two-dimensional finite element model is developed to simulate the interaction between metal samples and laser-induced shock waves. Multiple laser impacts are applied at each location to increase plastically affected depth and compressive stress. The in-depth and surface residual stress profiles are analyzed at various repetition rates and spot sizes. It is found that the residual stress is not sensitive to repetition rate until it reaches a very high level. At extremely high repetition rate (100 MHz), the delay between two shock waves is even shorter than their duration, and there will be shock wave superposition. It is revealed that the interaction of metal with shock wave is significantly different, leading to a different residual stress profile. Stronger residual stress with deeper distribution will be obtained comparing with lower repetition rate cases. The effect of repetition rate at different spot sizes is also studied. It is found that with larger laser spot, the peak compressive residual stress decreases but the distribution is deeper at extremely high repetition rates.

A Numerical Study on the Redistribution of Residual Stress After Machining

2017 ◽  
Author(s):  
Kunyang Lin ◽  
Wenhu Wang ◽  
Ruisong Jiang ◽  
Yifeng Xiong
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Numerical Study ◽  
Cutting Speed ◽  
Machining Process ◽  
Stress Profile ◽  
Residual Stress Field ◽  
Machining Processes ◽  
Residual Stress Profile

Machining induced residual stresses have an important effect on the surface integrity. Effects of various factors on the distribution of residual stress profiles induced by different machining processes have been investigated by many researchers. However, the initial residual, as one of the important factor that affect the residual stress profile, is always been ignored. In this paper, the residual stress field induced by the quenching process is simulated by the FEM software as the initial condition. Then the initial residual stress field is used to study the residual stress redistribution after the machining process. The influence of initial stress on the stress formation is carried out illustrating with the mechanical and thermal loads during machining processes. The effects of cutting speed on the distribution of residual stress profile are also discussed. These results are helpful to understand how initial residual stresses are redistributed during machining better. Furthermore, the results in the numerical study can be used to explain the machining distortion problem caused by residual stress in the further work.

A New Finite Element Approach Without Chip Formation to Predict Residual Stress Profile Patterns in Metal Cutting

2009 ◽  
Author(s):  
S. Anurag ◽  
Y. B. Guo ◽  
Z. Q. Liu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Hard Turning ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Stress Profile ◽  
Residual Stress Profile ◽  
Stress Prediction ◽  
Element Approach ◽  
Stress Profiles

Residual stress prediction in hard turning has been recognized as one of the most important and challenging tasks. A hybrid finite element predictive model has been developed with the concept of plowed depth to predict residual stress profiles in hard turning. With the thermo-mechanical work material properties, residual stress has been predicted by simulating the dynamic turning process followed by a quasi-static stress relaxation process. The residual stress profiles were predicted for a series of plowed depths potentially encountered in machining. The predicted residual stress profiles agree with the experimental one in general. A transition of residual stress profile has been recovered at the critical plowed depth. In addition, the effects of cutting speed, friction coefficient and inelastic heat coefficient on residual stress profiles have also been studied and explained.

Residual Stress in Plain Carbon Steel Induced by Laser Hardening

2015 ◽  
Vol 812 ◽  
pp. 321-326 ◽  
Author(s):  
A. Filep ◽  
Márton Benke ◽  
Valéria Mertinger ◽  
Gábor Buza
Keyword(s):  
Heat Transfer ◽  
Residual Stress ◽  
Residual Stresses ◽  
Plain Carbon Steel ◽  
Laser Hardening ◽  
Manufacturing Processes ◽  
Stress Profile ◽  
Multiple Sources ◽  
Residual Stress Profile ◽  
Hardening Treatment

Technological residual stresses have great importance in the manufacturing processes and the lifetime of components. The residual stresses formed by quenching can be very diverse because of its multiple sources. Alternative quenching processes such as laser hardening have a great potential for different applications. The direction of heat transfer during laser hardening is the opposite compared to conventional quenching. This further increases the complexity of the developed stress state. The residual stress profile and the microstructure formed by laser hardening treatment are investigated in the present manuscript.

Experimental/Modelling Study of Residual Stress in Al/SiCp Bent Bars by Synchrotron XRD and Slitting Eigenstrain Methods

2008 ◽  
Vol 571-572 ◽  
pp. 277-282 ◽  
Author(s):  
Xu Song ◽  
Solène Chardonnet ◽  
Giancarlo Savini ◽  
Shu Yan Zhang ◽  
Willem J.J. Vorster ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Residual Strain ◽  
Numerical Models ◽  
Front Face ◽  
Stress Profile ◽  
X Ray Diffraction ◽  
Element Analysis ◽  
X Ray ◽  
Residual Stress Profile

The aim of the study presented here was to evaluate the residual stresses present in a bar of aluminium alloy 2124-T1 matrix composite (MMC) reinforced with 25vol% particulate silicon carbide (SiCp) using X-ray diffraction and 3D profilometry (curvature measurement using Mitutoyo/Renishaw coordinate measurement machine) and comparing these results with numerical models of residual strain and stress profiles obtained by a simple inelastic bending model and Finite Element Analysis (FEA). The residual strain distribution was introduced into the test piece by plastic deformation in the 4-point bending configuration. At the first stage of this study the elasticplastic behaviour of the MMC was characterized under static and cyclic loading to obtain the material parameters, hardening proprieties and cyclic hysteresis loops. Subsequently, synchrotron Xray diffraction and CMM curvature measurements were performed to deduce the residual stress profile in the central section of the bar. The experimental data obtained from these measurements were used in the inelastic bending and FEA simulations. The specimens were then subjected to incremental slitting using EDM (electric discharge machining) with continuous back and front face strain gauge monitoring. The X-ray diffraction and incremental slitting results were then analysed using direct and inverse eigenstrain methods. Residual stresses plots obtained by different methods show good agreement with each other.

Numerical Analysis of the Effect of Machining on the Depth of Yield, Maximum Firing Pressure and Residual Stress Profile in an Autofrettaged Gun Tube

2003 ◽  
Vol 125 (3) ◽  
pp. 342-346 ◽  
Author(s):  
Amer Hameed ◽  
R. D. Brown ◽  
J. G. Hetherington
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Optimization Technique ◽  
Circumferential Stress ◽  
Element Model ◽  
Stress Profile ◽  
Residual Stress Field ◽  
Element Analysis ◽  
Residual Stress Profile ◽  
Experimental Findings

A multi-linear kinematic, two dimensional finite element model incorporating Bauschinger effect, developed using ANSYS commercial software is used to determine the effect of machining both at the bore and at the outside diameter, on the depth of yield, maximum firing pressure and final residual stress field present in an autofrettaged gun tube. The model, which is in good agreement with experimental findings, clearly shows that the reduction in maximum compressive circumferential stress is more sensitive to internal machining than to external machining; the depth of yield remains stable and there is no movement of the elastic-plastic interface, relative to its location before material removal. If the internal machining removes material in which reverse yield has occurred, the maximum firing pressure is not affected. The finite element analysis supported by experimental evidence thus leads to an optimization technique for gun tube design.

Detailed Analysis of Residual Stress Profile at Micro-Scale in Transmission Laser Bonded Titanium/Polyimide System

2008 ◽  
Author(s):  
Ankitkumar P. Dhorajiya ◽  
Mohammed S. Mayeed ◽  
Gregory W. Auner ◽  
Ronald J. Baird ◽  
Golam M. Newaz ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Laser Beam ◽  
Stress Analysis ◽  
Detailed Analysis ◽  
Stress Profile ◽  
Fe Model ◽  
Residual Stress Profile ◽  
Stress Profiles ◽  
Residual Stress Analysis

Detailed analysis of residual stress profile due to laser micro-joining of two dissimilar biocompatible materials, polyimide (PI) and titanium (Ti), is vital for the long-term application of bio-implants. In this work, a comprehensive three dimensional (3D) transient model for sequentially coupled thermo-mechanical analysis of transmission laser micro-joining of two dissimilar materials has been developed by using the finite element (FE) code ABAQUS, along with a moving Gaussian laser heat source. The laser beam (wavelength of 1100 nm and diameter of 0.2 mm), moving at an optimized velocity, passes through the transparent PI, gets absorbed by the absorbing Ti, and eventually melts the PI to form the bond. The laser bonded joint area is 6.5 mm long by 0.3 mm wide. First the transient heat transfer analysis is performed and the nodal temperature profile has been achieved, and then used as an input for the residual stress analysis. Non-uniform mixed meshes have been used and optimized to formulate the 3D FE model and ensure very refined meshing around the bond area. Heat resistance between the two materials has been modeled by using the thermal surface interaction technique, and melting and solidification issues have been approximated in the residual stress analysis by using the appropriate material properties at corresponding temperature. First the model has been used to observe a good bonding condition with the laser parameters like laser traveling speed, power, and beam diameter (burnout temperature of PI > maximum temperature of PI achieved during heating > melting temperature of PI) and a good combination has been found to be 100 mm/min, 3.14 W and 0.2 mm respectively. Using this combination of parameters in heating, the residual stress profile of the laser-micro-joint has been calculated using FE model after cooling the system down to room temperature of 27 °C and analyzed in detail by plotting the stress profiles on the Ti and PI surfaces. Typically the residual stress profiles on the PI surface show low value in the middle, increase to higher values at about 160 μm from the centerline of the laser travel symmetrically at both sides, and to the contrary, on Ti surface show higher values near the centerline of traveling laser beam. The residual stresses have slowly dropped away on both the surfaces as the distance from the bond region increased further. Maximum residual stresses on both the Ti and PI surfaces are at the end of the laser travel, and are in the orders of the yield stresses of respective materials.

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