Computational Modeling of Cellular Metals with Random Microstructures Brooks H. Smith, S.M.ASCE 1 ; Sanjay R. Arwade, A.M.ASCE 2 Abstract: Cellular metals made from aluminum, steel, titanium, or other metals are becoming increasingly popular as a stiff but lightweight material for use in structural components of automobiles, aircraft, and buildings. Finite element analyses have previously simulated foams by simplifying their microstructures to ideal periodic structures and then simulating unit cells. However, such simulations are physically unrealistic, and the data shows that there is a strong discrepancy between the model predictions and experimental results. We attempt to reduce this error by simulating two types of bulk closed-cell metal foams as random structures. Applied compressive displacements are imposed to most closely simulate standard uniaxial experimental test procedures. Initial results are presented, consisting of effective macroscopic stress strain curves, incremental Poisson’s Ratio, and a percentage of the material which has yielded. Some results are then compared with previously-published experimental data for validation purposes. Two parametric studies investigate the sensitivity of the macroscopic material properties to microstructural parameters. One, which simulates lotus-type foams, shows an increase in yield strength as voids are elongated and a decrease in the plastic Poisson’s Ratio as relative density is decreased. The other, simulating hollow spheres foams, varies the spheres size and relative density and shows a rough decrease in yield strength as sphere size decreases, and a rapid change in both the elastic and pla stic Poisson’s Ratios from about 0.15 to 0.3 is observed at a relative density of 15-20%. CE Database subject headings: Cellular structures; Computer aided simulation; Computer models; Heterogeneity; Material properties; Metals, material; Microstructures Introduction Cellular metals are becoming increasingly popular for use in structural components, though the relationship between many microstructural characteristics and the material’s effective macroscopic properties remains poorly defined. In particular, the relatively new metal foams made of steel are often manufactured by unique processes which produce microstructures that have not previously been explored. There are several possible microstructures for metal foams, though closed-cell foams present the most promise for structural applications due to their higher strength and stiffness properties. The most important of the closed-cell manufacturing methods include lotus-type, powder metallurgy, sintered hollow spheres, and composite hollow spheres. Each method results in different microstructures, some of which may be anisotropic, have different deformation mechanisms, or different stress concentrators. Existent mathematical models have tried to describe the 1 Graduate Research Assistant, Dept. of Civil & Environmental Eng., Univ. of M assachusetts at Amherst, Amherst, M A 01002 2 Assistant Professor, Dept. of Civil & Environmental Eng., Univ. of M assachusetts at Amherst, Amherst, M A 01002. E-mail: arwade@ecs.umass.edu