Quinn, S., Sambasivam, S. and Dulieu-Barton, J.M.
Derivation of the stress concentrations at holes in orthotropic plates using thermoelastic stress analysis
At SEM Annual Conference & Exposition on Experimental and Applied Mechanics - Experimental Mechanics of High Performance Systems.
07 - 09 Jun 2009.
An experimental study of the stress distribution around holes in orthotropic composite laminates has been
conducted using thermoelastic stress analysis (TSA). Quantitative thermoelastic studies of stress
concentrations in metallic plates is a straightforward matter, all that is required is the ratio of the response
from the hole and a far-field reading. For orthotropic materials the situation is more complex as the
response is not simply proportional to the sum of the principal stresses. In general the thermoelastic
response of an orthotropic laminate is a function of the stresses in the principal surface material directions
and the associated coefficient of thermal expansion. The approach in this paper is to obtain ‘stress
factors’ at the hole and identify the maxima in the plot. Specimens manufactured from a variety of
different laminate lay-ups (unidirectional (UD), cross-ply (CP), angle-ply (AP) and quasi-isotropic (QI)) are
considered. In all these cases the principal stress directions at the hole are not coincident with the
principal material directions and it is a challenging proposition to derive meaningful stress data from these
configurations. To validate the approach the experimental data are compared to analytical models. To
better understand the nature of the response finite element models are produced that mimic the
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