Exhausted jet caused the deformation of front metal seal covers in a multiple launch rocket system

Abstract

During the launch tests of a Multiple Launch Rocket System (MLRS), the front metal seal covers on unlaunched tubes had plastic deformation and felled to the ground. More seriously, the rocket exhausted jet directly caused damage to some of the unlaunched rockets projectiles. As the rocket exhausted jet impinged on the cover, high temperature and high pressure jet caused plastic deformation of the covers. So the temperature and pressure of exhausted jet acting on the surface of the cover were measured. Then pressure data were used to estimate the strain of front cover on adjacent launch tube caused only by pressure. And temperature data were used for thermal stress analysis of the cover. Furthermore, the triaxial strain curves of the cover were obtained during a flight test in which a 252-mm diameter rocket projectile was launched from the MLRS. The results demonstrated that plastic deformation of the covers is mainly due to the thermal deformation caused by the high temperature, which provided guidance for optimal design of front seal covers. No plastic deformation was found in the modified covers during subsequent launch tests of the MLRS.