PSI - Issue 5

Etienne Bonnaud et al. / Procedia Structural Integrity 5 (2017) 310–317

313

Author name / Structural Integrity Procedia 00 (2017) 000 – 000

4

Table 1. Selected runs for plates (original).

Table 2: Pair matrix for plates (original).

1 1 1 1 1 1

2 3 4 3 2 4

3 2 2 4 4 3

6 5 6 7 5 8

4 4 3 2 3 2

8 6 5 8 7 7

5 7 8 6 6 5

7 8 7 5 8 6

1 0 0 0 0 0 0 0 0

2 2 0 1 1 0 0 1 1

3 2 1 0 1 1 1 0 0

4 2 1 1 0 1 1 0 0

5 0 1 1 1 0 1 1 1

6 0 1 1 1 1 0 1 1

7 0 1 1 1 1 1 0 1

8 0 1 1 1 1 1 1 0

Run 1 Run 2 Run 3 Run 4 Run 5 Run 6

1 2 3 4 5 6 7 8

Fig. 4. Simulations results for the 6 selected runs. None of them gives a final displacement close to zero.

The optimization algorithm does find a sequence giving almost zero displacement but surprisingly simulation of this computed sequence gives a rather high displacement value. This indicates that the optimization procedure, as it is, does not work properly. A closer look at the kinematic of the problem gives the explanation of this malfunction. When an inner bead is deposited so that one of the inner layer (1-2) or (3-4) is for the first time completed, the resulting displacement is much higher than displacements for any of the other bead addition. This is illustrated in Fig. 5 where bead 2 welded after bead 1 (on the lower blue curve) gives approximatively -4mm displacement and bead 4 after bead 3 (on the upper red curve) gives approximatively +4mm displacement. Note that welding completion of the upper inner layer (1-2) gives a downwards displacement whereas welding completion of the lower inner layer (3-4) gives an upwards displacement. Expansion during heating, in those cases, dominates over contraction during cooling.

4

2

1

3

4

2

3

Fig. 5. Illustration runs. Bead 4 welded after bead 3 can give different displacement values, see black arrows.