Artificial Neural Network Modelling for Prediction of SNR Effected by Probe Properties on Ultrasonic Inspection of Austenitic Stainless Steel Weldments

Many austenitic stainless steel components are used in the construction of nuclear power plants. These components are joined by different welding processes, and radiation damages occur in the welds during the service life of the plant. The plants are inspected periodically with ultrasonic test methods. Many ultrasonic inspection problems arise due to the weld metal microstructure of austenitic stainless steel weldments. The present research was conducted in order to describe the affects of probe angle and probe frequency of both transversal and longitudinal wave probes on detecting the defects of austenitic stainless steel weldments. Feed forward back propagation artificial neural network (ANN) models have been developed for predicting signal to noise ratio (SNR) of transversal and longitudinal wave probes. Input variables that affect SNR output in these models are welding angle, probe angle, probe frequency and sound path. Of the experimental data, 80% is used for a training dataset and 20% is used for a testing dataset with 10 neurons in hidden layers in developed ANN models. Mean absolute error (MAE) and mean absolute percentage error (MAPE) types are calculated as 0.0656 and 16.28%, respectively, to predict performance of ANN models in a transversal wave probe. In addition, MAE and MAPE are calculated as 0.0478 and 18.01%, respectively, for performance in a longitudinal wave probe.

Effect of Taper Angle of the Optical Fiber Microprobe in Power Collection

The objective of this experiment is to study the effect of taper angle of the optical fiber microprobe in power collection. Optical fiber microprobes with taper angle from 10° to 23° were fabricated using the automatic fusion splicer by applying one-sided pulling and electric arc heating technique. It was found that the maximum power detected by a small taper angle probe was only -34.22dBm. The highest optical power collected by the optical fiber microprobe in this study was -25.01dBm with taper angle of 22.9°. Large taper angle probe receives more light at the tip which increases the sensitivity of the probe.