scholarly journals Experimental Techniques to Investigate Residual Stress in Joints

2018 ◽  
Author(s):  
Roberto Montanari ◽  
Alessandra Fava ◽  
Giuseppe Barbieri
Keyword(s):  
Residual Stress ◽  
Experimental Techniques

Study of through-thickness residual stress by numerical and experimental techniques

1998 ◽  
Vol 33 (6) ◽  
pp. 449-458 ◽  
Author(s):  
S Rasouli Yazdi ◽  
D Retraint ◽  
J Lu
Keyword(s):  
Residual Stress ◽  
Temperature Field ◽  
Stress Field ◽  
Boundary Conditions ◽  
Experimental Techniques ◽  
Hole Drilling ◽  
Residual Stress Field ◽  
Thermal Problem ◽  
Incremental Hole Drilling ◽  
Surface Convection

The quenching process of aluminium alloys is modelled using the finite element method. The study of residual stress field induced by quenching is divided into two: the thermal and mechanical aspects. In the thermal problem, the general heat conduction equation is solved and the temperature field during quenching is calculated. In the mechanical problem, the calculated temperature field and mechanical properties are used to predict the residual stress field. In this paper, the two different boundary conditions used in the thermal problem are examined. The first is surface convection using the appropriate heat transfer coefficient. The second is the temperature variation measured at the surface of the part. These boundary conditions are compared, and the advantages and the drawbacks of each are shown. The influence of different quenching parameters on the level of residual stress is studied. To validate the quenching modelling, the incremental hole drilling and neutron diffraction methods are used to measure the residual stress field in the studied parts. The hole drilling technique has been adapted to measure the residual stress through a larger thickness of the part. The aim of this paper is the combination of numerical and experimental techniques for the investigation of the through-thickness residual stress field.

Application of 3D Finite Element Modelling to Repair Weld Simulation in Industrial Applications

2002 ◽  
Author(s):  
George Vinas ◽  
Tamba Dauda ◽  
Nicola Moyes ◽  
Alan Laird
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Measurement Techniques ◽  
Fem Simulation ◽  
Welding Process ◽  
Industrial Applications ◽  
Welding Residual Stress ◽  
Experimental Techniques ◽  
Residual Stress Field

The Finite Element Method (FEM) has been implemented in 3D to predict welding residual stresses in repair welds. The analysis has been used to achieve more accurate residual stress predictions for the weld at the cost of long computation times. The use of this CPU intensive approach has been facilitated by the advent of ever-faster computer processors being made more accessible to the engineering community. The same technique has also been used with coarser meshes involving simplified welding sequences where a number of weld passes are “lumped” together to reduce the simulation time. The authors argue that this latter approach can be very useful in predicting the more global component response — in cases where 2D model symmetries are not applicable — and for rapid identification of problem areas where finer simulations would be prohibitive. The authors show an example of a residual stress prediction for a letterbox repair obtained using the FEM. Good agreement between this prediction and experimental measurements is shown. The FEM simulation technique has been used to predict residual stress formation during the welding process and subsequent service loading of the component. This analysis shows the residual stress field relaxation following “shakedown”. The component under service conditions is subjected to pressure loading and a small amount of bending stress. Based on recent residual stress experimental programmes conducted at Mitsui Babcock Energy Limited (MBEL), the authors provide a brief discussion on the ways in which various experimental techniques have been used to verify welding residual stress predictions from FE. The authors argue that just as there has been an interest in the field to measure residual stresses in the highly stressed regions of a weld, it is equally important to measure stresses in areas of relatively low stress to confirm that stresses do indeed die out away from welds. It is in the latter case where some experimental techniques cannot perform as well as other simple, well proven, strain measurement techniques.

TEM investigations of surface residual stress relaxation in A12O3 and Al2O3-SiC nanocomposite

1994 ◽  
Vol 52 ◽  
pp. 628-629
Author(s):  
J. Fang ◽  
H. M. Chan ◽  
M. P. Harmer
Keyword(s):  
Residual Stress ◽  
Single Phase ◽  
Stress Relief ◽  
Stress Recovery ◽  
Surface Residual Stress ◽  
Microscopic Mechanism ◽  
Sic Particles ◽  
Annealing Procedure ◽  
The Difference ◽  
Nano Size

It was Niihara et al. who first discovered that the fracture strength of Al2O3 can be increased by incorporating as little as 5 vol.% of nano-size SiC particles (>1000 MPa), and that the strength would be improved further by a simple annealing procedure (>1500 MPa). This discovery has stimulated intense interest on Al2O3/SiC nanocomposites. Recent indentation studies by Fang et al. have shown that residual stress relief was more difficult in the nanocomposite than in pure Al2O3. In the present work, TEM was employed to investigate the microscopic mechanism(s) for the difference in the residual stress recovery in these two materials.Bulk samples of hot-pressed single phase Al2O3, and Al2O3 containing 5 vol.% 0.15 μm SiC particles were simultaneously polished with 15 μm diamond compound. Each sample was cut into two pieces, one of which was subsequently annealed at 1300° for 2 hours in flowing argon. Disks of 3 mm in diameter were cut from bulk samples.

Residual stress measurements and modeling of built-up Box-T sections

2021 ◽  
Vol 160 ◽  
pp. 107336
Author(s):  
Ziqian Zhang ◽  
Gang Shi ◽  
Xuesen Chen ◽  
Lijun Wang ◽  
Le Zhou
Keyword(s):  
Residual Stress ◽  
Stress Measurements

Comparative study of the effective parameters on residual stress relaxation in welded aluminum plates under cyclic loading

2020 ◽  
Vol 21 (5) ◽  
pp. 505
Author(s):  
Yousef Ghaderi Dehkordi ◽  
Ali Pourkamali Anaraki ◽  
Amir Reza Shahani
Keyword(s):  
Residual Stress ◽  
Cyclic Loading ◽  
Stress Relaxation ◽  
Stress Amplitude ◽  
Cyclic Plasticity ◽  
Mean Stress ◽  
Effective Parameters ◽  
Perfect Plasticity ◽  
Residual Stress Relaxation ◽  
Aluminum Plates

The prediction of residual stress relaxation is essential to assess the safety of welded components. This paper aims to study the influence of various effective parameters on residual stress relaxation under cyclic loading. In this regard, a 3D finite element modeling is performed to determine the residual stress in welded aluminum plates. The accuracy of this analysis is verified through experiment. To study the plasticity effect on stress relaxation, two plasticity models are implemented: perfect plasticity and combined isotropic-kinematic hardening. Hence, cyclic plasticity characterization of the material is specified by low cycle fatigue tests. It is found that the perfect plasticity leads to greater stress relaxation. In order to propose an accurate model to compute the residual stress relaxation, the Taguchi L18 array with four 3-level factors and one 6-level is employed. Using statistical analysis, the order of factors based on their effect on stress relaxation is determined as mean stress, stress amplitude, initial residual stress, and number of cycles. In addition, the stress relaxation increases with an increase in mean stress and stress amplitude.

Sign in / Sign up

Export Citation Format

Share Document