EVALUATION OF NON-DESTRUCTIVE ULTRASONIC INSPECTION METHODS BASED ON STRUCTURAL INTEGRITY ASSESSMENT OF AXLES IN KKBW 50-TON FREIGHT WAGONS

• Main Author: maulana, Irwan
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/83085
• Institution: Institut Teknologi Bandung

The increase in railway transportation volume has significantly impacted the performance of critical components, especially axles. One of the main concern is the potential axle failure due to that can initiate fatigue cracks. Consequently, Non-Destructive Inspection (NDI) methods, such as ultrasonic testing, are performed regularly to detect cracks or defects before failure occurs. However, despite these measures, axle failures still occur, especially in freight trains. Recent incidents have shown that failures occur in the mid-span area of the axle, a location far from the ultrasonic scanning zone. Thus, the effectiveness of NDI methods becomes a crucial aspect to evaluate. The evaluation of inspection methods is closely related to the assessment of structural integrity based on the principle of damage tolerance. By incorporating the probability of detection from NDI methods, the concept of damage tolerance ensures the safety of axles during operation. This study examines the sensitivity of ultrasonic NDI methods on freight train axles in detecting defects or cracks and compares the results with the structural integrity assessment criteria outlined in BS 7910. Sensitivity testing of the NDI method was conducted on artificial defects in the mid-span area using full-scale axles. The test results showed that the NDI method could detect the smallest defect that has a depth of 4 mm with a very low signal indication of 2% full screen height (FSH). The NDI method was able to detect defects with a reasonably good detection signal of 16% FSH for defects size of 10 mm depth. Based on defect assessment using the failure assessment diagram (FAD) method, defects in this size range are in the safe region for structural integrity. In order to obtain accurate defect analysis results, this study used numerical simulation of the finite element method through ANSYS software. The analysis results for critical defect size showed that the critical defect size is when the crack reaches a depth of 80 mm.