Nonlinear Stress and Deformation Behaviour of Composite Sandwich Beams |
| Journal |
Applied Mechanics and Materials (Volumes 13 - 14) |
| Volume |
Advances in Experimental Mechanics VI |
| Edited by |
J.M. Dulieu-Barton, J.D. Lord and R.J. Greene |
| Pages |
91-98 |
| DOI |
10.4028/www.scientific.net/AMM.13-14.91 |
| Online since |
July, 2008 |
| Authors |
E.E. Gdoutos,
I.M. Daniel
|
| Keywords |
Deformation, Failure, Foam Core, Nonlinearities, Sandwich Beam |
| Abstract |
The nonlinear load-displacement and normal stress distribution in composite sandwich
beams made of unidirectional carbon/epoxy facings and PVC foam cores under bending was
studied. The carbon/epoxy after an initial linear response exhibits a stiffening nonlinearity in tension
and a softening nonlinearity in compression with the longitudinal strength in tension higher than
that in compression. The foam core also presents a nonlinear stress-strain response. It was obtained
that the load-displacement behaviour of the beam, after an initial linear part, is not linear. This
behavior was modeled by an incremental strength of materials nonlinear analysis. The theoretical
predictions were in good agreement with the experimental results. Furthermore, it was obtained that
the neutral axis of sandwich beams under bending does not pass through the centroid of the cross
section, but is displaced toward the tensile side of the beam. Experimental results by moiré
measurements of the in-plane horizontal displacements of the core material corroborated the
analytical predictions. These findings imply higher compressive and smaller tensile stresses in the
core, than those predicted for facings with identical stress-strain behaviour in tension and
compression, and should be taking into consideration in the failure analysis of sandwich beams. |
| Full Paper |
Download the paper
|
| Preview |
Free first page example |
