DEVELOPMENT OF NONDESTRUCTIVE TESTING BASED MULTI FREQUENCY ULTRASOUND WITH PULSE ECHO METHOD FOR INTERNAL DEFECT INSPECTION ON RAIL AND SIMULATION 3D USING K-SPACE PSEUDOSPECTRAL METHOD

• Main Author: Sinta
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/47137
• Institution: Institut Teknologi Bandung

Because of the rapid development of rail based transportation construction, inspection system of railroad infrastructure should be developed along to ensure the safety. Inspection system using nondestructive testing (NDT) based ultrasound is one powerful method to evaluate the internal condition of rail, such as deformation and crack. This paper uses the reflection of ultrasonic waves response (pulse-echo) to detect internal defects and time of flight to detect the depth of defect. Ultrasonic inspection systems have been extensively developed. The challenge is to obtain ultrasonic reflection waves that are compatible with railroad track’s geometric structure.. This paper presents a 3D simulation approach using the k-space pseudospectral method to simulate the propagation of ultrasound waves and beam pattern from transducer on R-54 railroad geometry, both in normal and with defect condition (line defects and plane defects). Simulations are used to determine the parameters of ultrasonic testing, such as transducer specification, wave propagation mode, and analysis of the result. This simulation is carried out using a 0.25 MHz frequency and 10 mm diameter transducer, and echo wave propagation mode, where one transducer is used as a transmitter and receiver transducer. This paper also presents an experimental approach to detect the depth of defects in the steel specimen medium and the R-54 railroad sample. The ultrasonic testing system consist of an ultrasonic pulser-receiver module, ultrasonic transducer, digital oscilloscope, and water as a couplan. This test is carried out with variations of transducer frequency, namely 2.5 MHz, 4 MHz, and 5 Mhz. Ultrasonic testing of steel specimens produced an average relative error 2.31% for the 2.5 MHz frequency; 3.40% for the 4 MHz frequency; and 2.43% for the 5MHz frequency. As for testing on R-54 railroad sample, the average relative error is 1.24% for 2.5 MHz frequency; 0.67% for the 4 MHz frequency; and 0.94% for the 5 MHz frequency. Overall, an ultrasonic testing system designed using a 4 MHz frequency transducer provides the best performance with a value of R2 = 0.9997 in determining the depth of internal defects.