The experiments were performed on plates having an initial transversal deformation with magnitude of 9.6 mm to determine the results obtained by numerical tests, such as:
– variation of the transversal displacement (w) of the point placed in the middle of the plate, on the surface, function of in-plane loading magnitude (p);
– variation of the strains in the certain point placed so on the concave face and on the convex face of the plate.
The measurements were done with the stretching machine, displacement transducer, strain gauge measurement system. In figure AA5, the plate and equipment used for experiments are shown.
Fig. 17.5. Test rig and imperfect composite plate
To assure the boundary condition on the plate sides a special very rigid frame was made. So, the plate is clamped on three sides and simple supported on the side where the pressure is acting.
Fig. 17.6. Variation of compression load versus displacement of the point placed in the middle of the plate
In the figure AA6, the results obtained from experiments are plotted with dots. Acceptable deviations between numerical and experimental results, for the transversal displacement of the point placed in the middle of the plate, are observed. In the figures only the elastic range of the curve is presented, because the experiment was made in this domain. In the abscise, a gap for pression corresponds to a force AF = 1 kN.