NOMENCLATURE
CHAPTER 5 Results and discussions
A. Numerical thermo-mechanical analysis
5.4 Comparative study of residual stress and angular deformation of single and double sided fillet joints
5.4.2 Comparison of residual stresses distributions
First of all the residual stresses distribution for fillet welding joints were validated with published literature [186]. The comparison between the estimated results and results from published literatures of longitudinal and transverse residual stress for single sided fillet welded joint are shown in Figures 5.28 and 5.29 respectively. Same parameters were used for the numerical analysis at the present work. A good agreement can be observed in both the cases of longitudinal and transverse residual stresses. After validating the present developed model, it was used to study the residual stresses distribution both in single and double sided fillet welding.
0 10 20 30 40 50 60 70 80 90 -200
-100 0 100 200 300 400 500
Longitudinal residual stress (MPa)
Distance perpendicular to welding direction (mm) Published results [186]
Present results
Figure 5.28 Comparison of longitudinal residual stress with published literature [186]
0 15 30 45 60 75 90
0 40 80 120 160
Transverse residual stress (MPa)
Distance perpendicular to weld line (mm)
Published results [186]
Present results
Figure 5.29 Comparison of transverse residual stress with published literature [186]
The contour plots of longitudinal, transverse and von-Misses residual stress distribution for single sided fillet welding are shown in Figure 5.30. Figure 5.31 (a, b & c) represents the longitudinal, transverse & von-Misses residual stress distribution pattern for double sided fillet welding.
Figure 5.30 (a) Longitudinal, (b) Transverse and (c) von-Misses residual stress distribution for single sided fillet welding
The maximum value of longitudinal and transverse residual stresses are found to be 415 MPa and 173 MPa respectively for single sided fillet welding which is shown in the Figure 5.31 (a
& b). It can also be seen from the Figure 5.30 (c) that the maximum magnitude of von-Misses residual stress distribution is 371 MPa. Overall, it is observed that within and proximity to the welding region stress distribution is tensile in nature and away from the weld line it is compressive in nature. As the temperature gradient is maximum at the weld zone, during solidification of the molten metal the weld zone solidifies rapidly thus shrinkage occurs and it pulls the adjacent materials. Therefore the residual stress in the weld zone is always tensile in nature. But away from the weld line i.e. in the heat affected zone the temperature gradient is less and it takes more time to get cooled. To balance the weld shrinkage force induced by the weld zone it applies a counter force. Therefore residual stress is compressive in nature away from the weld line.
Figure 5.31 (a) Longitudinal, (b) Transverse and (c) von-Misses residual stress distribution for double sided fillet welding
From Figure 5.31, same pattern of residual stress distribution is observed as of the single sided weld. The maximum amount of longitudinal and transverse residual stress is found to be 405 MPa and 145 MPa respectively. The maximum amount of von-Misses residual stress is found to be 355 MPa.
Figure 5.32 shows the comparison of longitudinal residual stress distribution between single and double sided fillet welding from centre of base plate to perpendicular to the welding direction. Comparison of transverse residual stress distribution between single and double sided fillet welding is shown in Figure 5.33. Figure 5.34 shows the comparison of von-Misses residual stress distribution between single and double sided fillet welding. The comparison
between the longitudinal & transverse residual stress along the weld line of single and double sided fillet welds are shown in Figures 5.35 & 5.36 respectively.
-80 -60 -40 -20 0 20 40 60 80
-100 0 100 200 300 400
450 Middle of base plate i.e.
mid section of stiffner
For single sided fillet welding For double sided fillet welding
Distance transverse to weld line (mm)
Longitudional residual stress (MPa)
Line for taking residual stress Weld line
Figure 5.32 Comparison of longitudinal residual stress distribution
-80 -60 -40 -20 0 20 40 60 80
0 20 40 60 80 100 120 140
160 Middle of base plate i.e.
mid section of stiffner
For single sided fillet welding For double sided fillet welding
Distance transverse to weld line (mm)
Transverse residual stress (MPa)
Weld line
Line for taking residual stress
Figure 5.33 Comparison of transverse residual stress distribution
-80 -60 -40 -20 0 20 40 60 80 0
50 100 150 200 250 300 350 400
von-Misses residual stress (MPa)
Distance transverse to weld direction (mm) Middle of base plate i.e.
mid section of stiffner
For single sided fillet welding For double sided fillet welding
Weld line
Line for taking residual stress
Figure 5.34 Comparison of von-Misses residual stress distribution
0 20 40 60 80 100 120 140 160
0 100 200 300 400 500
Distance along weld direction (mm)
Longitudinal residual stress (MPa)
For single sided fillet welding For double sided fillet welding
Line along which data taken
Weld Bead
Figure 5.35 Comparison of longitudinal residual stress distribution along weld line
0 20 40 60 80 100 120 140 160
-300 -225 -150 -75 0 75
150 For single sided fillet welding For double sided fillet welding
Distance along weld direction (mm)
Transverse residual stress (MPa)
Line along which data taken
Weld Bead
Figure 5.36 Comparison of transverse residual stress distribution along weld line
For same welding parameters the magnitude of both longitudinal and transverse residual stresses are more in case of single sided fillet welding as shown in Figures 5.35 & 5.36. At the beginning of transient stage the residual stress raises to a maximum value and it remains almost constant throughout the entire weld length i.e. along the quasi stationary region. This is because at the initial transient stage the temperature is raising and final transient i.e. at end of the weld length the temperature is decreasing but at the mid region i.e. at the quasi stationary region, the peak temperature remains almost constant. From the above Figures 5.32 to 5.36 it can be observed that the maximum magnitude of the residual stresses for single sided weld is more than the double sided ones.