AN EXPERIMENTAL STUDY OF STRESSES AT THE INTERFACE OF PROPELLANT GRAINS AND MOTOR CASES DUE TO THERMAL LOADING OF THE SHRINKAGE TYPE.
Progress rept. no. 1,
CATHOLIC UNIV OF AMERICA WASHINGTON D C STRESS ANALYSIS LABS
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The objective of the research program is the experimental study of stresses present at the interface between solid propellant rocket grains and their motor cases due to thermal loading of the shrinkage type. Of particular concern are the stresses at the end of the bonded interface between grain and case. The proposed approach of the program consists of photoelastic analysis of two- and three-dimensional models of the solid-propellant rocket grain shapes when subjected to shrinkage while bonded to a motor case. It is planned to analyze a number of two-dimensional shapes of the meridian cross-section of the grain and, from these, choose the most informative for the more elaborate three-dimensional analysis. With the use of these two-dimensional models an attempt is made to simulate in an approximate way the stress and strain distribution found in the more elaborate three-dimensional models. In the program reported here, a number of urethane rubber models were cast and shrunk on steel strips with various crosssections.