Residual Stress Correlation in Two Different Mitigation Techniques Using FEA

Abstract

Many techniques were developed to control residual stress and distortion during welding process to minimizes their magnitude in the affected area. Due to complicity to find qualitative analysis for welding residual stress and distortion in real experiment work, the numerical simulation of welding process give a good solution to helpful the process and evaluated extensive analysis. In the present paper two different residual stress mitigation techniques moving cooling spot and moving heating spot were investigated in thin welded sheet structure using FEA. Thermo mechanical analysis and simulation of the processes were performed by ANSYS. The obtained results show different residual stresses behaviour developed during welding, the residual stress magnitude were minimized in both used techniques especially in trailing heat sink welding process. The out of plane distortion results show successfully eliminating of cambering distortion, it is also found that the effective elimination are based on the proper position parameters with respect to the welding heat source.

Contemporary approaches to reducing weld induced residual stress

“…7 Following the convention of Guan et al [165], this process is alternatively referred to as Low Stress No Distortion (LSND) welding. Efforts to model the process agree that relief of residual stress is greatest with a very localised and intense cooling source, positioned as close behind the welding heat source as possible (see Figure 11) [109,112,113,110]. Various researchers have used different cooling media: solid CO2 'snow' [114,115,116] and argon-atomised water [107] have featured in recent studies.…”

“…11). 109,112,113,110 Various researchers have used different cooling media: solid CO 2 snow114,115,116 and argon-atomised water107 have featured in recent studies. Liquid nitrogen has also been suggested as a suitable coolant,110,117 however, it does not appear to have been tested experimentally in any study to date.…”

“…12 b ). 126 For transient tensioning, a suitably intense heat source is required, and various researchers have investigated the use of flame heaters,122,124,126 laser spots,113,120 and induction heaters127 for this purpose. Of course, in all cases the mechanism by which the stress state in the weld is changed (via thermal dilation of part of the material), is fundamentally the same.…”

Development of Predicted Stress and Strain during Conventional and after Mitigation of Welded Aluminium-Manganese Alloy

“…The cooling media can be fluid or gas, which do not affect the properties of the welded material. Simulations of the intense cooling effects are expressed in the literature [13,18]. The technique parameters and some related physical properties can be found in Ref.…”

“…Many cooling media like compressed air, water, argon gas, helium gas and liquid nitrogen can be used. The predicted longitudinal residual stress using this technique exhibited a balancing of stress distribution at above and below the neutral axis [13,14].…”