PDF Publication Title:
Text from PDF Page: 258
9/8/98 AC 43.13-1B 5-89. GENERAL. Ultrasonic inspection is an NDI technique that uses sound energy moving through the test specimen to detect flaws. The sound energy passing through the specimen will be displayed on a Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD) computer data program, or video/camera me- dium. Indications of the front and back sur- face and internal/external conditions will ap- pear as vertical signals on the CRT screen or nodes of data in the computer test program. There are three types of display patterns; “A” scan, “B” scan, and “C” scan. Each scan pro- vides a different picture or view of the speci- men being tested. (See figure 5-15.) 5-90. SOUND REFLECTION. The amount of reflection that occurs when a sound wave strikes an interface depends largely on the physical state of the materials forming the interface and to a lesser extent on the specific physical properties of the material. For exam- ple: sound waves are almost completely re- flected at metal/gas interfaces; and partial re- flection occurs at metal/liquid or metal/solid interfaces. 5-91. ULTRASONIC INSPECTION TECHNIQUES. Two basic ultrasonic in- spection techniques are employed: pulse-echo and through-transmission. (See figure 5-16.) a. Pulse-Echo Inspection. This process uses a transducer to both transmit and receive the ultrasonic pulse. The received ultrasonic pulses are separated by the time it takes the sound to reach the different surfaces from which it is reflected. The size (amplitude) of a reflection is related to the size of the reflecting surface. The pulse-echo ultrasonic response pattern is analyzed on the basis of signal am- plitude and separation. b. Through-Transmission Inspection. This inspection employs two transducers, one to generate and a second to receive the ultra- sound. A defect in the sound path between the two transducers will interrupt the sound trans- mission. The magnitude (the change in the sound pulse amplitude) of the interruption is used to evaluate test results. Through- transmission inspection is less sensitive to small defects than is pulse-echo inspection. 5-92. FLAW DETECTION. Ultrasonic in- spection can easily detect flaws that produce reflective interfaces. Ultrasonic inspection is used to detect surface and subsurface disconti- nuities, such as: cracks, shrinkage cavities, bursts, flakes, pores, delaminations, and po- rosity. It is also used to measure material thickness and to inspect bonded structure for bonding voids. Ultrasonic inspection can be performed on raw material, billets, finished, and semi-finished materials, welds, and in- service assembled or disassembled parts. In- clusions and other nonhomogeneous areas can also be detected if they cause partial reflection or scattering of the ultrasonic sound waves or produce some other detectable effect on the ultrasonic sound waves. Ultrasonic inspection is one of the more widely-used methods of NDI. 5-93. BASIC EQUIPMENT. Most ultra- sonic inspection systems include the following basic equipment; portable instruments (fre- quency range 0.5 to 15 MHz), transducers (longitudinal and shear wave), positioners, ref- erence standards, and couplant. a. Ultrasonic Instruments. A portable, battery-powered ultrasonic instrument is used for field inspection of airplane structure. (See figure 5-17.) The instrument generates an Par 5-89 Page 5-41 SECTION 7. ULTRASONIC INSPECTIONPDF Image | AFS-640
PDF Search Title:
AFS-640Original File Name Searched:
ac_43.13-1b_w-chg1.pdfDIY PDF Search: Google It | Yahoo | Bing
5,000 BF Shipping Container Lumber Dry Kiln For Quality Lumber The 5,000 BF container kiln consists of one 40 foot high-cube aluminum shipping container... More Info
Shipping Container Lumber Dry Kilns by Global Energy Global Energy designed and developed the container kiln back in 1991. The purpose is to give access to portable sawmill owners, furniture makers, and small business the value added profit of dry kiln lumber and quality hardwoods... More Info
Vacuum Kiln Conversion Kit for Lumber and Wood Dry Kilns Convert your existing conventional dry kiln into a fast drying vacuum kiln. Similar to vacuum bagging in the boat building and aircraft industry, we have come up with a proprietary process which allows you to build a very simple vacuum kiln at a fraction of the price, and without the intensive conventional metal chamber structure... More Info
Vacuum Pump Cart System for Bagging Clamping Wood Drying and more Vacuum Cart with 2HP Pump and Dual Pistons with multiple multiplex vacuum ports and liquid reservoir... More Info
Vacuum Bagging Basics Vacuum bagging is a method of clamping, which has traditionally been used in the composites industry, but can also be used for vacuum drying materials, including wood products... More Info
CONTACT TEL: 608-238-6001 Email: greg@globalmicroturbine.com (Standard Web Page)