**4.3. Distortions**

Fig. 19 illustrates the distortions of the welding structure due to the welding sequences. The initial undeformed configurations were also shown. From Fig. 19, it can be seen the angular distortions occurred in both flanges. It can be further revealed that there was the difference of distortion between the flanges showing that the distortion was unsymmetrical. The maximum value of angular distortion took place on the right flange for all the welding sequences, unless that of WS-2 which took place on the left one. The simulation results obtained also clearly indicate the influence of the welding sequences examined in the present study to the angular distortions of the T-joint fillet weld considering the same boundary conditions appliedin the corresponding FEM models of the T-joint fillet weld.

3D Finite Element Simulation of T-Joint Fillet Weld:

(X = 100 mm) Angular distortion

difference

Effect of Various Welding Sequences on the Residual Stresses and Distortions 603

The right flange

Angular distortion [rad]

*U*y [mm] [rad]

*U*y [mm]

1 0. 897 0. 0090 1. 005 0. 0101 0. 0011 3 0. 755 0. 0076 0. 990 0. 0099 0. 0023 2 2. 344 0. 0240 0. 897 0. 0090 0. 0150 4 0. 783 0. 0078 0. 812 0. 0081 0. 0003

Welding sequence (WS)

temperature.

welding.

The left flange (X = -100 mm)

> Angular distortion [rad]

**Table 3.** The vertical displacements and the angular distortions of both flanges due to the WS.

From the results, it seems that, for the problem considered in this numerical study, two welding sequences, namely WS-2 and WS-4, have taken the attention. The WS-2, which is called as simple alternating welding, has produced the lowest peak temperature and the smallest longitudinal and transverse residual stresses as well. Meanwhile the WS-4, which is called as multiple crossing welding, has produced the smallest angular distortion and angular distortion difference, although it produced the highest peak

The information appears to be consistent with respect to the welding sequences performed. The corresponding value of the von Mises stress and the distortion difference produced as shown respectively in Table 2 and 3 indicated this as well. In particular, the results were also in contrast to those of WS-1 and WS-3. Not only did the welding sequences produce high angular distortions, but also they resulted in relatively high values of the von Mises stresses. Furthermore, the distortion results obtained appears to be match with the ones usually found in the welding practice incorporating alternating

Also, considering limited literatures concerning welding simulation of T-joint fillet welds in 3D (Chang & Lee, 2009 and Deng et al., 2007), the results obtained would be very valuable

**4.4. Discussions and recommendation for further research** 

Furthermore, Table 3 summarizes the vertical displacements and the angular distortions of both flanges due to the welding sequences. The angular distortion differences were also shown in Table 3.

**Figure 19.** Distortions of the welding structure due to the welding sequences: (a) WS-1, (b) WS-2, (c) WS-3, and (d) WS-4.


**Table 3.** The vertical displacements and the angular distortions of both flanges due to the WS.
