Results 1 - 10 of 701
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[en] Based on the idea of eigen-mode expansion, a method to analyze the reflection of Lamb wave from a finite vertical discontinuity of plate is theoretically derived and verified by experiment. The theoretical prediction is in good agreement with the experimental result, and this strongly suggests that eigen-mode expansion method could be used for solution of inverse scattering problem for ultrasonic testing using Lamb wave
[en] The results of crack evaluation by conventional UT(Ultrasonic Test)is highly depend on the inspector's experience or knowledge of ultrasound. Phased array UT system and its application methods for small crack length evaluation will be a good alternative method which overcome present UT weakness. This study was aimed at checking the accuracy of crack length evaluation method by electronic scanning and discuss about characteristics of electronic scanning for crack length evaluation. Especially ultrasonic phased array with electronic scan technique was used in carrying out both sizing and detect ability of crack as its length changes. The response of ultrasonic phased array was analyzed to obtain the special method of determining crack length without moving the transducer and detectability of crack minimal length and depth from the material. A method of crack length determining by electronic scanning for the small crack is very real method which has it's accuracy and verify the effectiveness of method compared to a conventional crack length determination
[en] n EMAT field, spiral RF coils are much more widely used when compared with solenoid coils. In the field of the magnetostrictive strip transducers for long range ultrasonic testing of cylindrical structures, however, solenoid coils has been used. This seems to be attributed to the difficulty in fabricating low frequency (i.e., large size) spiral coils. In this paper, we describe a method for fabricating spiral coil magnetostrictive strip guided wave transducers from FFC (flexible flat cable). It is demonstrated through a comparison experiment that the spiral coil transducer has much superior performance (sensitivity, SNR, and guided wave direction control capability) than the previous transducer with solenoid coils
[en] Inspection of dissimilar metal welds using phased array ultrasound is not easy at all, because crystalline structure of dissimilar metal welds cause deviation and splitting of the ultrasonic beams. Thus, in order to have focusing and/or steering phased array beams in dissimilar metal welds, proper time delays should be determined by ray tracing. In this paper, we proposed an effective approach to solve this difficult problem. Specifically, we modify the Oglivy's model parameters to describe the crystalline structure of real dissimilar metal welds in a fabricated specimen. And then, we calculate the proper time delay and incident angle of linear phased array transducer in the anisotropic and inhomogeneous material for focusing and/or steering phased array ultrasonic beams on the desired position
[en] In the previous study, we have developed an ultrasonic measurement system and analysis technique for burning rate testing of solid propellants using ultrasound. So, in this study, we performed measurement of composite solid propellant, which has linear burning rate as pressure increasing, using the developed system in order to evaluate capability of ultrasonic method. Furthermore, accuracy of measured burning rates using ultrasound was verified by comparison to burning rate measured by the strand burner method.
[en] We generally use Radiographic Testing and Ultrasonic Testing to find out internal flaw of material. Ultrasonic Testing is easy to detect inner flaw depth and then we have the purpose to measurement the depth location of defect in the inner part of Testing material using the Radiographic Testing. But for the test, operator should knowledge of testing material and have a plenty of knowledge and experience about Ultrasonic Testing. And there isn't much storge for discovered flaws. Radiographic Testing saves the results of testing in the film. However it provides the result in the 2-dimensional phase which has a difficulty of guessing the depth of flaw. Parallax Method is one of methods that present a 3-dimensional phase. And yet if the testing material is thin, the measuring tolerance is high and can't measure the accurate depth. ON the basis of Parallax Method, we analogize a depth of flaw using a change in thickness of flaw image and find out how much tolerance can occur compared to an actual flaws.
[en] Large scaled ships, manufactured inside of the country, should be passed welding inspection and painting film inspection. Normally, these kind of inspections are conducted by human inspectors manually, although it cause industrial disasters such as falling accidents and diving accidents frequently. In addition, Ship makers are not to give a full trust to ship owners because manual inspections cannot be conducted all over the welding parts. So, in this study we developed an automated ultrasonic TOFD inspection system using an welding line tracing robot. This system, controlled by an inspector at a remote field, can inspect welding parts of ship outer panel both under water and in air. In this paper we present the developed robot and ultrasonic TOFD inspection system and the inspection result.
[en] The durability and quality of concrete (repairs) are directly related to the type of mortar, ambient conditions, correct advice (as to repair) and the skills of the person performing the work. The classical method is destructive testing following the EN 1542:1999 - testing the tensile bound strength of concretes. The measure procedure and the results are often subject for discussion caused by interpretation difference of the value found and a wrong decision may be possible. A non-destructive scanner has been developed with SME partners in an EU CRAFT-project to verify the bonding quality of concrete. Two prototype called CUBE-1 and -2 have been built during the project and both prototypes were field tested. They are based on ultrasonic technologies. The testing of CUBE-2 has shown that it is easy-to-use, it is able to measure different thickness layers up to 60 mm and to measure concrete with a grain size up to 8 mm. It is also able to measure good and bad bonds of smooth surfaces up to 2 mm but it is not yet suitable to measure on very rough surfaces up to 5 mm. Now a new ultrasonic scanner, CUBE-3, has been developed to overcome some limitations of CUBE-2, for instance CUBE-3 is expected to have a depth range of 300 mm. CUBE-3 is now ready for practical field testing
[en] Large scaled ships, manufactured inside of the country, should be passed welding inspection and painting film inspection. Normally, these kind of inspections are conducted by human inspectors manually, although it cause industrial disasters such as falling accidents and diving accidents frequently. In addition, Ship makers are not to give a full trust to shipowners because manual inspections cannot be conducted all over the welding parts. So, in this study we developed an automated ultrasonic TOFD inspection system using an welding line tracing robot. This system, controlled by an inspector at a remote field, can inspect welding parts of ship outer panel both under water and in air. In this paper we present the developed robot and ultrasonic TOFD inspection system and the inspection result.
[en] Eddy current standard for the calibration of absolute type surface probe and the technique of measurement of the dimensions of artificial slot in the standard was developed. The ultrasonic test method was applied for measuring depth of the artificially machined slot of which width and depth were 0.1 mm and 0.5 mm respectively. The developed technique of measuring such narrow and deep slot with uncertainty of 0.02 mm for depth has been unattainable by this time.