Experimental investigation and constitutive modeling of metallic honeycombs in sandwich structures
Name
54663383-MIT.pdf
Description
Full printable version
Size
21.04 MB
Format
Adobe PDF
Checksum (MD5)
8532969c0614129203f68acfc86c5b37
Author(s)
Mohr, Dirk, 1976-
Advisor(s)
Tomasz Wierzbicki.
Date Issued
2003
Publisher
Massachusetts Institute of Technology
Abstract
Traditionally, honeycomb sandwich structures are designed in the elastic range, but recent studies on the crushing of sandwich profiles have shown their potential in crashworthiness applications. Thin sandwich sheets also hold a promise for widespread use in automotive industry because standard sheet metal forming technology could be used to produce double-curvature sandwich shell structures. The crashworthiness and formability of sandwich structures are critically dependent on the behavior of the sandwich core under large plastic deformation. In this thesis, a new biaxial testing device has been developed for the reliable characterization of the mechanical behavior of cellular materials. Using this device, the macroscopic phenomenology and the underlying microstructural deformation mechanisms of thin-walled aluminum honeycomb have been studied experimentally for combined out-of-plane shear and normal loading. Furthermore, numerical simulations of the experiments have been performed where the cell walls of the specimen microstructure have been discretized with fine shell element meshes. Based on the experimental and numerical results, a finite-strain rate-independent orthotropic constitutive model for metallic honeycombs has been formulated and implemented into commercial finite element software. The good agreement of the model predictions with the experimental results encourages the use of this constitutive model for applications involving large plastic out-of-plane deformation. On the structural scale, the model has been used to predict the crushing response of a thin-walled sandwich profile with a micro-cell stainless steel honeycomb core.
Description
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.
Includes bibliographical references (p. 207-214).
Subjects
Civil and Environmental Engineering.
MIT Department
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
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