PSI - Issue 21

B. Paygozar et al. / Procedia Structural Integrity 21 (2019) 138–145 B. Paygozar, S.A. Dizaji / Structural Integrity Procedia 00 (2019) 000 – 000

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tube diameter will improve the absorbed energy capacity. In the third diagram where the outer tube diameter is fixed, the absorbed energy can be improved by increasing the thickness while it is almost insensitive to the diameter ratio. Likewise, Fig. 6d indicates that in the models with the same thicknesses, those of lesser outer tube diameter can absorb the energy more effectively. The negligible effect of the diameter ratio on the amount of dissipated energy was also investigated in Fig. 7. However, it can be concluded that the designs with S=1.6 are more feasible ones having optimal dissipated energy.

S=1.6

S=1.4

(a)

(b)

t out =14 mm

D out =405 mm

(c) (d) Fig. 6 Coupled effects of dimensional variations of different case studies on the amount of absorbed energy; a) S=1.4, b) S=1.6, c) D out =405 mm and d) t out =14 mm.

0 10 20 30 40 50

40

t=8 mm t=12 mm

t=10 mm t=14 mm

t=8 mm t=12 mm

t=10 mm t=14 mm

30

20

10

Absorbed energy (kJ)

Absorbed Energy (kJ)

0

1.35

1.45

1.55

1.65

1.75

1.35

1.45

1.55

1.65

1.75

Diameter ratio

Diameter ratio

(a) (b) Fig. 7. Comparisons between the amounts of absorbed energy in terms of the diameter ratio and the thickness of the outer tube, a) D=390 mm, b) D=420 mm.