Experimental techniques for predicting fatigue failure of cannon-breech mechanisms

In this paper a technique for predicting thread fatigue behavior for full-scale cannon-breech mechanisms from small-specimen tests is investigated. A thread load-distribution factor is determined experimentally for the breech ring and breech-block components by measurement of the thread fillet strains at breech-chamber pressures of 49,500 psi. A comparison of small-specimen thread fatigue data with the results of full-scale breech-component test results is given for several thread geometries.