Abstract
The ideal boundary of a discontinuity is defined as that boundary along which there is no stress concentration. Photoelastically an isochromatic coincides with the ideal boundary. This property is used to develop experimentally ideal boundaries for some cases of technological interest. The concept of ‘coefficient of efficiency’ is introduced to evaluate the degree of optimization. The procedure to idealize boundaries is illustrated for the two cases of the circular tube and of the perforated rectangular plate, with prescribed functional restraints and a particular criterion for failure. An ideal design of the inside boundary of the tube is developed which decreases its maximum stress by 25 percent, at the time it also decreases its weight by 10 percent. The efficiency coefficient is increased from 0.59 to 0.95. Tests with a brittle material show an increase in strength of 20 percent. An ideal design of the boundary of the hole in the plate reduces the maximum stresses by 26 percent and increases the coefficient of efficiency from 0.54 to 0.90.
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Durelli, A.J., Brown, K. & Yee, P. Optimization of geometric discontinuities in stress fields. Experimental Mechanics 18, 303–308 (1978). https://doi.org/10.1007/BF02324161
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DOI: https://doi.org/10.1007/BF02324161