engleski

Simulation of Ultrasonic Pulse Propagation Through Multiple Curved Boundaries

Non-destructive testing (NDT) methods are regularly applied as part of in-service inspection to verify the integrity of structures during their exploitation. Flooded Member Detection (FMD) is an underwater NDT method utilised to detect penetration of water in hollow underwater structure elements (members) of off-shore platforms. Since ultrasonic NDT techniques are commonly used for FMD, the geometrical positioning of ultrasonic probes in relation to a structure member is a very complex problem in real testing conditions. Therefore, we analyse ultrasonic signal responses regarding the range of probe geometry displacements that occur in practical situations. Theoretical and numerical modelling, based on the linear dynamic theory of isotropic elastic materials, formulate a system of equations describing the geometrical path of the ultra¬sonic pulse propagation through multiple curved boundaries. Numerical simulations were per¬formed for several characteristic sets of parameters by using the software package MATLAB. The results obtained with a simulation model show an agreement with experimental re¬sults obtained on a laboratory mock-up model, pointing to a significant influence of the posi¬tion and orientation of ultrasonic probes on the reliable interpretation of ultrasonic response.

underwater ultrasonic Flooded Member Detection; beam reflection and refraction; mode conversion; curved acoustic boundaries

nije evidentirano