Experimental study on the effects of the boundary conditions on the deformations of composite plates

In this study, the effects of the boundary conditions on the out-of-plane displacements and through-the-thickness strain distribution of symmetric composite laminated plates are reported. The plates are subjected to bending by a central force and supported by two-line or four-point supports. The out-of-plane displacement field is measured using a full field electronic speckle pattern interferometry technique and the through-the-thickness distribution of the deformations by fibre Bragg gratings, embedded at selected locations during preparation of the plates. The experimental data are correlated with the results from elasticity-based 2D and 3D finite element models of the actual experimental configuration. The results clearly exhibit the effects of the boundary conditions on the deformation behaviour of the plates. Non-linear through-the-thickness strain distributions appear in the thick plate range. Aspects such as force and displacement distributions on the contact areas of both loading and supports are also considered.