Obtaining geometries of real cracks and using an efficient finite element model to simulate their ultrasonic array response

摘要

Stress corrosion cracks are a serious issue in many industries. They can grow quickly and cause catastrophic failure, so it is imperative to be able to reliably inspect for them. However, the branched nature of these cracks causes difficulties when inspecting with a single ultrasonic transducer. An ultrasonic array is more suited to this application because it can inspect at many angles. In order to efficiently design an array, it is necessary to understand the ultrasonic scattering from these complex cracks. In this paper, images of real stress corrosion cracks are obtained by performing X-ray Computed Tomography of parts that have been removed from service. Image processing software is used to extract the crack geometry. An efficient, frequency-domain finite element model is described and validated for simulating scattering from branched cracks. This model is incorporated into a hybrid model and used to simulate array data from real cracks. This process will enable an optimal array design and the highest defect detection sensitivity.