Numerical investigation on infrared thermal wave detection method used for the coated bonding quality of different materials in solid rocket motors

Focus on the problem of the Solid Rocket Motor (SRM) coated bonding quality detection, to investigate the influence of different materials and different heating methods on the quality of the bonding quality detection, the numerical simulation study was conducted by using the method of infrared thermal wave nondestructive testing (NDT). Based on the finite element method and the transient heat conduction equation, a simplified model of the SRM was established and the boundary conditions were determined to solve the model. The theoretical analysis and simulation results show that the maximum temperature difference detected by the shell surface is different and the best inspection time is also different according to the different heating methods, different heating time and different shell materials. Heating the aluminum plane by point light, the defect location and depth could be obtained by figuring out the abnormal temperature area, the obvious degree of defect and defect depth, the deeper the defect, the larger the size, the more easily detected. It also has the ability of achieving the quantitative measurement. Take a uniform heating method, compared with the composite material shell, the best inspection time for using metal material shell is relatively short and the detection is more difficult. Therefore, the optimal heating method and the best inspection time can be selected for different shell materials, which lays a solid foundation for the applied research of solid rocket engine coating and bonding quality testing.