AN EXPERIMENTAL ANALYSIS OF THERMAL STRAIN ONSOLID MOTOR SAFE DEVICE
固体发动机保险机构在高温高压下的实验研究

Laser speckle method and strain gages have been used to investigate the mechanical behavior of solid motor safe device. Thermal creep can occur when the device works under high temperature and high pressure. Large deformation can be produced during this course. An improved speckle technique which allows measurement of continuous and large deformation is suggested. Two pieces of hologram, instead of one in tradition, are used to accept speckles from the specimen at each load step. Displacement information can be extracted by comparing two holograms at different load step optically. The process can reduce effect of rigid-body displacement. Based on analysis by speckle technique a model solid motor is designed to examine the mechanical behavior of safe device. The experimental results show that a very high stress zone exists in the structure. Not only high pressure and high temperature but also the geometry of the structure induces the high stress. It is one of main failure mechanisms of safe device. Compressive thermal stress is produced in the "high stress zone" because safe device is refrained at the bound by motor shell. This thermal stress seems to reduce the high tensile stress due to high inner pressure. However, nearly 400 high temperature leads to deterioration of the mechanical properties of material. Improvements are suggested.