Abstract: Discontinuities such as voids and porosities have considerable effects on metallic components failure. Time of flight diffraction (TOFD) technique is based on sending ultrasound waves into the material and receiving them as electrical signals or images. Interpreting the acquired signals assist inspectors to defects detection and their morphology characterization. Defect orientation and its overall size are two significant factors influencing the obtained signal and eventually calculation of the crack depth and its length. In this research, a two-dimensional numerical model of TOFD is developed and utilized to simulate and analyze the obtained signal in a steel block which has cylindrical voids. Then, crack depth and its length are determined using the simulated signal. The model and corresponding signal are utilized to investigate effects of crack orientation and overall size on its depth and length calculation of TOFD. The obtained results assist in understanding wave-flaw interaction for any kind of cracks especially for the inclined voids.
Authors:A. Zolfaghari, D. Shahriari, and A. Zolfaghari
Keywords: Nondestructive testing, Ultrasonic inspection, Time of flight diffraction (TOFD), Defect, Steel