Experimental studies on the quasi-static axial crushing of steel columns filled with aluminium foam

Experimental investigations are carried out in order to study the e€ects of di€erent tube and ®ller arrangements on the crushing behaviour of axially compressed tubular crush elements. To this end quasistatic experiments are performed on monotubal and bitubal, empty and ®lled steel pro®les with di€erent materials, dimensions and cross- sectional shapes. Aluminium foam, produced by a powder metallurgical production process, is applied as ®ller material. The test results con®rm that considerable mass eciency improvements with respect to energy absorption may be obtained, even if reduced stroke lengths, caused by the presence of foam, are taken into account. Distinct di€erences are pointed out between the di€erent cross-sectional shapes. Bitubal arrangements, consisting of outer and inner pro®les with foam in between, are shown to be particularly ecient crush elements, as long as global failure can be avoided. Explanations for the experimental observations are obtained by a simpli®ed analysis of interaction e€ects. Constraints concerning the appropriate choice of Al-foam densities are summarized, too, in order to provide an aid for the future design of `optimally tunedʹ crush elements composed of tubular members and Al- foam.