Ultrasonic inspection methods of Non-Destructive Testing (NDT) use beams of sound waves (vibrations) of short wavelength and high frequency, transmitted from a probe and detected by the same or other probes. The sound energy is propagated in the material in form of longitudinal or shear wave modes and is ideal for the detections of two dimensional types of defects, cracks, delaminations, fusion defects. Usually, pulsed beams of ultrasound are used and in the simplest instruments a single probe, hand held, is placed on the specimen surface. During an ultrasonic inspection, an oscilloscope display with a time base shows the time it takes for an ultrasonic pulse to travel to a reflector (a flaw, the back surface or other free surface) in terms of distance traveled across the oscilloscope screen. The height of the reflected pulse is related to the flaw size as seen from the transmitter probe. The relationship of flaw size, distance and reflectivity are complex, and a considerable skill is required to interpret the display. Complex mutiprobe systems are also used with mechanical probe movement and digitization of signals, followed by computer interpretation are developing rapidly. Through the use of ultrasonic inspection test principles, internal material flaws can be detected and evaluated. Depending on the test application and or part configuration, inspection may be accomplished in either contact or immersion methods.
Ultrasonic inspection methods of Non-Destructive Testing (NDT) use beams of sound waves (vibrations) of short wavelength and high frequency, transmitted from a probe and detected by the same or other probes. The sound energy is propagated in the material in form of longitudinal or shear wave modes and is ideal for the detections of two dimensional types of defects, cracks, delaminations, fusion defects.
ReplyDeleteUsually, pulsed beams of ultrasound are used and in the simplest instruments a single probe, hand held, is placed on the specimen surface. During an ultrasonic inspection, an oscilloscope display with a time base shows the time it takes for an ultrasonic pulse to travel to a reflector (a flaw, the back surface or other free surface) in terms of distance traveled across the oscilloscope screen. The height of the reflected pulse is related to the flaw size as seen from the transmitter probe.
ReplyDeleteThe relationship of flaw size, distance and reflectivity are complex, and a considerable skill is required to interpret the display. Complex mutiprobe systems are also used with mechanical probe movement and digitization of signals, followed by computer interpretation are developing rapidly.
ReplyDeleteThrough the use of ultrasonic inspection test principles, internal material flaws can be detected and evaluated. Depending on the test application and or part configuration, inspection may be accomplished in either contact or immersion methods.