Series Solution and Stress Analysis of Rectangular Plate With Mixed Boundary Conditions

Stress functions expressed from Fourier series, suitable for arbitrary stress boundary conditions, were derived using method of variable separation. General displacement expressions containing the displacement of rigid body were also derived. A method of solving mixed boundary problems (in which external forces acting at a part of the whole boundaries are known and displacements at the rest boundaries are known) was presented. As an example, a rectangular plate, one side of which was fixed and objective side was subjected to a concentrated force, was analyzed. In addition, characteristics of stress distributions in the regions of stress concentration were questioned. It was found from the presented results of calculation that describing stress concentration with the singular stress at a point was unworkable. Describing stress concentration with the average stress in the feature size instead of the singular stress at a point was operative and reflected objectively practical stress and displacement boundary conditions. The concept of feature-size-factor was introduced.