Abstract
The overall yield strength of rectangular bar specimens with double symmetrical U-shaped notches of unequal depth and/or unequal radius was analysed by the upper and lower bound theorems. The occurance of interference between the two notches was thus studied. The yield strength for double notches became smaller because of the interference than that for a single notch. The amount of decrease in yield strength decreased with an increase of the difference in notch depth; so did the minimum distance between the notches at which the interference occurs. The interference did not occur below a certain distance. The difference in notch depth had stronger influence on the interference than the difference in notch radii. These analytical results can be easily applied to study the interference for double symmetrical notches of equal notch depth and equal notch radius, double symmetrical cracks and also for the combination of an extremely large notch radius and an extremely small notch radius.
