Simulating Modulated Thermography of Cladding Debond in Solid Rockets

Modulated infrared thermal wave nondestructive testing(IR NDT) is an advanced technique of internal flaw inspection,and has certain application prospect in detecting cladding debond in solid rocket motors(SRM).The numerical simulation of modulated IR NDT for cladding debond in SRM is carried out by using finite element method,and the influences of heating condition and structure on the detectability are studied.The evolutions of informative parameters(i.e.the amplitude,phase and phase difference of surface excessive temperature) versus heating condition(i.e.the modulation frequency and heat flow intensity) and structural parameters(i.e.materials,defect size,depth and thickness) are obtained.The optimal modulation frequency,blind frequency and phase difference for typical material and structural size are predicted.Modulated thermography can be used in detecting cladding debond in SRM,and the test condition can be optimized through computer simulation.