Elasto-plastic stress analysis in simply supported thermoplastic laminated plates under thermal loads

In this study, an elasto-plastic stress analysis is carried out on symmetric cross-ply [0 degrees /90 degrees](2) and symmetric angle-ply [30 degrees/-30 degrees](2), [45 degrees/-45 degrees](2), [60 degrees/-60 degrees](2) thermoplastic laminated plates. Laminated composite plates are simply supported and subjected to constant temperature change through the thickness. An analytical solution is performed for satisfying thermoelasto-plastic stress/strain relationships and boundary conditions for small plastic deformations. The composite materials are assumed to be perfectly plastic. The Tsai-Hill theory is used as a yield criterion. Residual stress components, (sigma (x))(r) and for cross-ply laminated plates have some magnitudes but (tau (xy))(r) are zero. The magnitudes of residual stress components increase gradually depending on the temperature increment. For symmetric angle-ply laminated plates, residual stresses are found zero except (tau (xy))(r). (C) 2001 Published by Elsevier Science Ltd. All rights reserved.