Critical Crack Size Investigation Method for a Land Launcher

Anotace: Structural integrity evaluation of military systems is vital in such applications as rocket launchers. In safe life design, for a certain operational life the system is ensured to function well and no failure would occur even in the presence of some imperfections or flaws. This paper considers the fracture analysis as part of the safe life design approach that is used in the design of a rocket launcher. A methodology based on sub modelling technique is introduced. It was made sure that unstable crack growth would not occur upto certain crack sizes. Subsequently, after actual manufacturing of the launcher, critical locations of welds in the system were checked for presence of any cracks after repeated firing loads. After these controls no cracks were detected due to operational conditions until the time when this document was prepared.