Vol. 3, No. 7, 2008

Download this article
Download this article For screen
For printing
Recent Issues

Volume 12
Issue 3, 249–351
Issue 2, 147–247
Issue 1, 1–146

Volume 11, 5 issues

Volume 10, 5 issues

Volume 9, 5 issues

Volume 8, 8 issues

Volume 7, 10 issues

Volume 6, 9 issues

Volume 5, 6 issues

Volume 4, 10 issues

Volume 3, 10 issues

Volume 2, 10 issues

Volume 1, 8 issues

The Journal
Cover
Editorial Board
Research Statement
Scientific Advantage
Submission Guidelines
Submission Form
Subscriptions
Author Index
To Appear
 
ISSN: 1559-3959
Quasistatic deformation and failure modes of composite square honeycombs

Benjamin P. Russell, Vikram S. Deshpande and Haydn N. G. Wadley

Vol. 3 (2008), No. 7, 1315–1340
Abstract

Carbon fibre epoxy matrix composite honeycombs have been fabricated by slotting, assembling and adhesively bonding composite laminate sheets with various fibre architectures. Their out-of-plane compressive and in-plane shear responses were measured as a function of relative density, ratio of the cell height to width and the number of cells in the specimen. The measurements indicate that the response is relatively insensitive to the ratio of the cell height to cell width and number of cells in the specimen but is strongly dependent on the laminate type and fibre orientation. For example, the compressive strength of the honeycombs made from 0 90 laminates with fibres aligned with the compression direction was greater than that of honeycombs made from a woven material with fibres at ± 45. However, the shear strengths exhibited the opposite trend. These differences were attributed to a change in failure mode. In compression the honeycombs failed by either elastic buckling or plastic microbuckling while in shear the two main failure modes were elastic buckling or shear failure of the composite sheet material. Analytical models are derived for these collapse modes and used to predict the strength of the honeycomb structure. The predicted strengths are substantially higher than the measurements due to the presence of manufacturing imperfections in the honeycombs that are not accounted for in the analytical models. A limited finite element (FE) investigation is also reported to quantify the effects of imperfections on the compressive strength of the composite honeycombs. The measurements and analytical predictions reported here indicate that composite cellular materials such as honeycombs reside in a gap in the strength versus density material property space, providing new opportunities for lightweight, high strength structural design.

Keywords
mattice materials, composites, microbuckling, honeycomb, carbon fiber, carbon fibre
Milestones
Received: 21 February 2008
Revised: 23 May 2008
Accepted: 1 June 2008
Published: 1 September 2008
Authors
Benjamin P. Russell
Engineering Department
Trumpington Street
University of Cambridge
Cambridge CB2 1PZ
United Kingdom
Vikram S. Deshpande
Engineering Department
Trumpington Street
University of Cambridge
Cambridge CB2 1PZ
United Kingdom
Haydn N. G. Wadley
Department of Materials Science and Engineering
University of Virginia
395 McCormick Road
Charlottesville VA 22904
USA