PHOTOELASTIC STUDY OF SKEW PLATES IN TRANSVERSE BENDING - 1.

A comprehensive study has been made, using the laminated plate-photoelastic technique, of the bending moment distributions in a thin skew plate subjected to a uniformly distributed load or a concentrated load and simply supported along its two opposite sides. The distribution of sums of principal bending moments was determined by solving Poisson's equation numerically with the boundary conditions obtained photoelastically. The effects of the membrane stresses and twisting moment were corrected satisfactorily. The distribution of the principal bending moments, sum and difference of the principal bending moments and twisting moments over the entire area of the plate together with the map of directions of principal bending moments were obtained in each of about 260 combinations of shape factors of the skew plate and loading parameter. An analytical solution for a special case of square plate under a concentrated load was worked out to verify the accuracy of the experimental procedure employed and the comparison of the results obtained experimentally and theoretically indicates that the accuracy of the procedure is satisfactory. In the present first part of the paper, the basic principle, experimental techniques and theoretical verification of the procedure are described in detail. The particular data obtained by the systematic experiments will be given in the succeeding parts.