cross section crash boxes
cross section crash boxes
cross section crash boxes
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(a) (b) (c) (d)<br />
Figure 3.7. Simulations of the deformation mode of circular tubes with circumferential<br />
imperfections; a/t ratios a) 5%, b)10%, c)50% and d)100% (Source: Galip<br />
and Liman 2004).<br />
The static and dynamic crushing behavior of thin walled circular stainless steel,<br />
mild steel and Al alloy tubes were investigated (Hsu and Jones 2004). Energy efficiency<br />
factor was defined as total elastic and plastic strain energy absorbed by a structural<br />
member divided by the energy absorbed in the same volume of material up to the failure<br />
in tension for evaluating the <strong>crash</strong>worthiness level of structure. It was reported that<br />
stainless steel circular tubes absorbed the highest energy among the tested tubes (Figure<br />
3.8). However, calculated energy efficiency factor of stainless steel circular tube was<br />
found the lowest for both the quasi-static and impact loading. The critical specimen<br />
length for the transition from the efficient progressive buckling to the catastrophic<br />
global bending for quasi-static loading was found to be similar for three tubes. The<br />
critical tube length of the transition was shown to increase with increasing impact<br />
velocity.<br />
The crushing behavior of circular CR 1018 steel tubes with groove patterns was<br />
studied experimentally and numerically,(Mamalis, et al. 2003c). Model and simulations<br />
showed similar deformation modes (Figure 3.9(a) and (b)). The initial peak load value<br />
of grooved tube was found to be lower than that of non-grooved tube (Figure 3.9(c)).<br />
The number of grooves was found not to affect the peak load values in both experiments<br />
and simulations, while the number of load peaks and the values of mean load decreased<br />
with increasing number of grooves (Figure 3.9 (d)).<br />
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