Mechanical Behavior of Metallic Hollow Sphere Materials: Experimental Study
Publication: Journal of Aerospace Engineering
Volume 21, Issue 4
Abstract
Different from conventional metal foams, sintered metallic hollow sphere (MHS) material contains a certain volume fraction of enclosed pore space inside the spheres, as well as the interstitial porosity between the sintered neighbors, and this mixed open/closed-cell characteristic offers low density, high stiffness, and good energy absorption capacity. It is a new type of prospective light weight material for automotive and aerospace industry. In this study, the mechanical properties, especially the dynamic behaviors of the MHS materials are examined experimentally. Basic geometrical measurements reveal that the two types of MHS specimens we used were composed of randomly packed hollow spheres with uniform outer radius (0.9 and ) and wall thickness (relative density ). A very long, plateau length (up to 67% nominal strain) with almost constant stress was found in quasi-static tests, indicating that they are appropriate for energy absorption applications. Dynamic tests were performed by using a modified split Hopkinson pressure bar (SHPB), and significant dynamic strength enhancements were observed. Moreover, based on the experimental observations the relevant collapse and dynamic enhancement mechanisms are discussed, whereas the localization phenomena in dynamic crushing process were revealed by using the particle image velocimetry correlation method.
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Acknowledgments
This study is a part of a project supported by the Hong Kong Research Grant Council (RGC) under Grant No. HKUST 6079/00E. A grant under the France/HK Joint Research Scheme (F-HK16/02T-11) made the collaboration between two institutions possible. The Fraunhofer Institute IFAM supplied the MHS materials. All this support is gratefully acknowledged.
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Information & Authors
Information
Published In
Journal of Aerospace Engineering
Volume 21 • Issue 4 • October 2008
Pages: 206 - 216
Copyright
© 2008 ASCE.
History
Received: Dec 1, 2006
Accepted: Nov 29, 2007
Published online: Oct 1, 2008
Published in print: Oct 2008
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