A shear wave from an angle beam transduce progress through a flat test piece by reflecting from the surface at points called nodes. Iaea tecdoc 462 ultrasonic testing of materials at level 2 training manual for non destructive testing techniques a technical document issued by the international atomic energy agency vienna 1988.
Ultrasonic testing in most common ut applications very short ultrasonic pulse waves with center frequencies ranging from 0 1 15 mhz and occasionally up to 50 mhz are transmitted into materials to detect internal flaws or to characterize materials.
Skip distance ultrasonic testing. Q r refracted sound wave angle. 1 shows on the vertical axis the signal height or amplitude and on the horizontal axis the time taken for the signal to return to the receiver and therefore distance from the transmitter. Leg 1 l 1 sound path in material to 1 st node.
18th world conference on nondestructive testing 16 20 april 2012 durban south africa ultrasonic multi skip inspection at clamped saddle supports maarten lorenz 1 stefan lewandowski 2 1 shell global solutions. Leg 2 l 2 sound path in material from 1 st to 2 nd node. Note down the db for the beam path distance.
Or hsd t x tan ø. The oscilloscope screen in fig. Skip distance surface distance of two successive nodes.
Position the probe on the reference block and note the gain required to bring the target echo to 40 fsh at a beam path length as close as possible 1 2 skip distance. Total round trip distance ultrasonic pulses travel 6 7 5 sound path travel time time it takes for ultrasonic pulses to travel along the sound path travel distance 6 7 4 6 7 6 skip distance full skip distance on the test surface 6 2 1. Hsd half skip distance fsd full skip distance tan ø perpendicular bg base ag ac or hsd thk.
Ultrasonic testing ut is a non destructive testing techniques based on the propagation of ultrasonic waves in the object or material tested. This method of examination is known as an a scan and is the most common method in use in industry for the examination of welded. Similarly fsd 2t x tan ø.
Skip distance is the distance needed in the base material to allow the entire weld to be scanned inspected vs v path helps you determine where an actual disconuity would may be located. Hence tan ø hsd t. The linear distance between two successive nodes on same surface is called skip distance.
And 1 1 2 skip distance 3t x tan ø.