Probability of detection simulations to study the influence of surface roughness on the reliability of ultrasonic testing system

The influence of the material's surface roughness on ultrasonic echo signals has been well studied and documented in the literature. However, these studies were mostly based on the monitoring of absolute value of the echo amplitude, which cannot quantify a defect's detectability. In this work, the influence of the surface roughness on the Probability of Detection (POD) of a defect is studied using POD simulations to provide quantitative and insightful analysis. Furthermore, POD simulations are used to quantify the influence of surface roughness on the parameters of ultrasonic testing procedure. A steel block having non-metallic inclusions type of defects was inspected by simulations using CIVA software. The inspection used the ultrasonic immersion pulse-echo setup with straight beam and angle beam techniques. Comprehensive POD curves are obtained, discussed and analyzed.