Experimental investigation and constitutive modeling of metallic honeycombs in sandwich structures

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.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2003

Author dc:creator

• Mohr, Dirk, 1976-

Advisor dc:contributor.advisor

• Tomasz Wierzbicki.

• Civil and Environmental Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/29754

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/29754