Modelling Ultrasonic Inspection of Rough Defects
Ultrasonic signals are affected by the nature of the defects under investigation. One defect property known to alter signal amplitudes and pulse shapes is surface roughness. No exact theory is available to describe the interaction of ultrasonic waves with rough defects but approximate theories are of great value, over various regimes of validity [1,2]. We have combined one such approximation. Kirchhoff theory [1,2], with many aspects of a real inspection system, to provide a model for simulating the ultrasonic inspection of randomly rough defects. The model is currently acoustic, such that mode conversion effects cannot be predicted. This paper presents some details of the model, together with sample results. These include a comparison with experimental measurements from rough surfaces, showing favourable agreement.