While primary thermal stress analysis of pin grid arrays considers a nonflexible card and module delineating the structure, in this paper we consider the stress relief (resulting in a “secondary” force system) afforded by bending and stretching of the delineating plates. The primary axial force F, plate moments, M1, M2, and shear V are considered acting in radial planes, and the secondary pin forces P are solved by stipulating compatibility of deformations at the two pin ends. A collocation technique is used to evaluate the plate equations in polar symmetry. The contributions of transverse plate compliances, and in-plane compliances are evaluated numerically for a 50 mm ceramic module, and compared with known experimental force measurements.

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