Probability of detection for surface-breaking holes with low-frequency eddy current testing – a non-linear multi-parametric approach

The evaluation of non-destructive testing (NDT) methods in terms of reliability is an increasing demand in various industries and applications. The probability of detection (POD) is the most frequently used method for this task. In the testing of holes with low-frequency eddy current testing, the frequently-used one-parametric POD approach cannot be used because the requirements, mainly the linearity, cannot be met.

Therefore, the use of a multi-parametric non-linear regression approach to calculate the POD is proposed. Instead of numerical simulations, commonly used in multi-parametric approaches, an analytical model is used.

The goal of this work is to evaluate the reliability of the eddy current system for the testing of electron-beam welded copper canisters by calculating a POD with the help of different artificial hole-like defects. In this example, the multi-parametric non-linear regression approach is shown to be successful, enabling the combination of depth and diameter in the POD calculation.