Dynamic compressive strength properties of aluminium foams. Part i - Experimental data and observations

John Harrigan, P J Tan, Shuguang Li, Stephen Reid, Zhenmin Zou

Research output: Contribution to journalArticlepeer-review

Abstract

This study of the dynamic compressive strength properties of metal foams is in two parts. Part I presents data from an extensive experimental study of closed-cell Hydro/Cymat aluminium foam, which elucidates a number of key issues and phenomena. Part II focuses on modelling issues. The dynamic compressive response of the foam was investigated using a direct-impact technique for a range of velocities from 10 to 210ms-1. Elastic wave dispersion and attenuation in the pressure bar was corrected using a deconvolution technique. A new method of locating the point of densification in the nominal stress-strain curves of the foam is proposed, which provides a consistent framework for the definition of the plateau stress and the densification strain, both essential parameters of the 'shock' model in Part II. Data for the uniaxial, plastic collapse and plateau stresses are presented for two different average cell sizes of approximately 4 and 14 mm. They show that the plastic collapse strength of the foam changes significantly with compression rate. This phenomenon is discussed, and the distinctive roles of microinertia and 'shock' formation are described. The effects of compression rates on the initiation, development and distribution of cell crushing are also examined. Tests were carried out to examine the effects of density gradient and specimen gauge length at different rates of compression and the results are discussed. The origin of the conflicting conclusions in the literature on the correlation between nominal strain rate ε̇ (ratio of the impact velocity Vi to the initial gauge length lo of the specimen) and the dynamic strength of aluminium alloy foams is identified and explained. © 2005 Elsevier Ltd. All rights reserved.
Original languageEnglish
Pages (from-to)2174-2205
Number of pages31
JournalJournal of Mechanics and Physics of Solids
Volume53
Issue number10
DOIs
Publication statusPublished - Oct 2005

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