Tensile strength of a closed-cell al foam in the presence of notches and holes

Abstract

School of Mechanical & Production Engineering, Nanyang Technological University,Singapore-639798(Received December 18, 1998)(Accepted in revised form January 26, 1999)IntroductionMetallic foams have many applications such as packaging of delicate electronic components, cores oflight-weight structural sandwich panels, and sound and energy absorption applications. The requirementof improved structural efficiency with relatively low cost has created interest in cellular materialsrecently [1]. The properties of foams can be made to vary significantly, depending on the choice ofcell-wall material, the volume fraction of the solid and the geometry of the structure [2]. Sugimuraetal. [3] and Grenestedt [4] assessed the roles of cell morphology and of imperfections in governing thebasic properties such as stiffness, yield strength and fracture resistance. In view of emerging applica-tions, detailed characterization of mechanical behavior of metal foams is an important task in order toassess their performance. In some applications of foams, it may be necessary to introduce holes ornotches for fastening and these can cause a severe drop in load bearing capability of the component. Anunderstanding of the behavior of foams in the presence of notches will be helpful in the design. Theobjective of this study is to develop such an understanding. In particular, our objective is to examineif the notch sensitivity characteristics of metallic foams are similar to those of fully dense metals. In thiswork, an experimental investigation is carried out on a closed cell Al foam and the preliminaryexperimental observations are presented here.ExperimentalA closed cell aluminum alloy foam material (supplied by Shinko Wire Company Ltd, Japan) with thetrade name ALPORAS was used in this study. It is processed by adding about 5 wt.% Ca (to enhancethe viscosity) and 3 wt.% TiH