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Numerical and Experimental Study of Diamond Collapse of Thin Wall Tube Energy-Absorber with Caps under Dynamic Axial Loading

Alireza Nadaf Oskouei

^1*

Hossein Khodarahmi

²

, Mojtaba Pakian Booshehri

³

Department of Mechanical Engineering, Imam Hossein Comprehensive University, Tehran, Iran P.O.B. 16535-187 Tehran, Iran, [email protected]

A RTICLE I NFORMATION A BSTRACT

Original Research Paper Received 29 October 2014 Accepted 27 November 2014 Available Online 27 December 2014

One of the most important devices for absorbing energy of the impact is circular tubes which absorb energy in different modes of plastic deformation. But one of the most important modes of deformation is dynamic progressive buckling caused by the axial collapse. This mode has the most energy absorption. In this study, the behavior of thin walled tubes (with caps) which have fossa near the end edges of the tube has been investigated in numerical and experimental way. This is contrary to the previous researches on energy absorption which used the quasi-static form. To carry out experimental tests, drop hammer machine has been used. In the numerical part, capabilities of Abaqus have been employed. The results show that caps improve energy absorption, thus more energy is absorbed in less length crushing, and the up and down fossa of the tube causes the maximum collapse force to occur with delay. Also, these absorbers have linear behavior in absorbing energy with respect to the crushing length and the average collapse force has not been changed by increasing the hammer weight. An experiment was conducted to assess the collisions with the same kinetic energy to study strain rates in four collisions. It was seen that reduction of 16.9 percent in strain rate increases 2.6 percent of the crushing length.

Keywords:

Absorbing energy Circular tubes

Dynamic Progressive buckling Diamond Collapse

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Numerical and Experimental Study of Diamond Collapse of Thin Wall Tube Energy-Absorber with Caps under Dynamic Axial Loading

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