Experimental Stress Analysis of Rocket Motor Casing using Elasto-Plastic Strain Theory

The purpose of rocket motors isto generate thrust or impulsive force to be passed on aninclined velocity to flight vehicle to transport its payload to its requiredtarget. It will be subjected to high pressure loads and temperature during the operating conditions of the motor mechanism. So, while selecting the material for the manufacturing of motor case, utmost care has to be taken, because the material chosen has to withstand all kinds of structural and thermal loads acting on it.15CDV6 steel is one of the latest trends, used in the design of rocket motors due to its high strength and hardness. The unique quality of 15CDV6 steel is that, it is a hypo-elastic material. This paper intends to analyze and evaluate the performance of 15CDV6 steel in its elasto-plastic range. Three specimens of the material were evaluated with the help of tensile tests and strain gauge data. For calculations, plane stress condition has been considered. From the resulting design parameters, a code was developed on the digital computer using Microsoft Excel, to create data sheets which produce stress data as output, when strain data is given as input. This code is also helpful in quickly analyzing the material behaviorby finding the factor of safety for the casing.