An exact formulation is presented of the relationship between the effective elastic constants for thick perforated plates (generalized plane strain) and thin perforated plates (plane stress). Extensive numerical results covering a wide range of ligament efficiencies and Poisson’s ratios are given for plates with square and triangular penetration patterns.

Results are reported of strain-controlled, low-cycle fatigue experiments conducted on annealed AISI 304, 316, and 348 stainless steels at temperatures of 430, 650, and 816 C with strain rates of approximately 4 × 10-3, 4 × 10-4, and 4 × 10-5 s-1. The investigation generally shows that fatigue life measured in terms of sustained loading cycles is affected adversely by the increase in temperature and by the decrease in strain rate. The test results were generated with servo-controlled, hydraulic testing machines using inductively heated hourglass-type specimens. Cyclic stress-strain data are compared with monotonic stress-strain data obtained from tension tests performed at the same temperatures and strain rates.

A finite-element computational method is employed to determine the spatial distribution of stress and strain in a notched-plate fatigue specimen fabricated of mild steel. Because of cyclic strain softening of the material, there is a redistribution of stress and strain in the specimen as a function of the number of load cycles. This phenomenon is considered in the analysis by using cyclic stress-strain diagrams as effective stress-strain curves. The numerical results are found to correlate well with measured strain distributions reported in the literature.

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