In order to study the influence of the stiffened structure on acoustic emission(AE)signal propagat-ing,the propagation characteristics of the AE signal in the stiffened plate and the stiffened cylindrical shell are studied by theoretical calculation,numerical simulation,and experiment.Based on the proposed multi-path propagation model,the installation constraints for the sensor are derived,which can highlight the signal scat-tered from the stiffened structure in the time domain.On this basis,the propagation of AE signals with different frequencies in stiffened structures with different heights is numerically simulated,and the propagation character-istics of AE signals are quantitatively characterized by the constructed reflection coefficient and transmission co-efficient.The accuracy of numerical simulation is verified by experiments.The results show that the AE signal will be reflected and transmitted at the stiffener,and other modes will evolve along with the modal conversion.Reflection and transmission coefficients show nonlinear characteristics with respect to the excitation frequency and the height of the stiffener.The higher the excitation frequency is the more sensitive the reflection and trans-mission coefficients are to the change of the stiffener height This study clarifies the propagation mechanism of the AE signal in the stiffened structure and can provide specific guidance for optimizing the spatial layout of sen-sors in AE monitoring.
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