Papers by Keyword: Non-Destructive Inspection

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Authors: Xia Li, Fei Fei Li, An Nan Jiang
Abstract: Georadar has many advantages, including good accuracy, high detecting capabilities, and user friendly results (data collected is shown pictorially thus easy to read). In addition, it has capabilities to provide real time information in field. In the present paper, the authors investigated the application of georadar in non-destructive inspection of Karst Cave underneath independent foundation. The results obtained improve our understanding of geometry and provide a foundation for effectively control the design and construction processes.
19
Authors: Sang Woo Choi, Joon Hyun Lee
Abstract: The reactor vessel body and closure head are fastened with the stud bolt that is one of crucial parts for safety of the reactor vessels in nuclear power plants. It is reported that the stud bolt is often experienced by fatigue cracks initiated at threads. Stud bolts are inspected by the ultrasonic technique during the overhaul periodically for the prevention of failure which leads to radioactive leakage from the nuclear reactor. The conventional ultrasonic inspection for stud bolts was mainly conducted by reflected echo method based on shadow effect. However, in this technique, there were numerous spurious signals reflected from every oblique surfaces of the thread. In this study, ultrasonic phased array technique was applied to investigate detectability of flaws in stud bolts and characteristics of ultrasonic images corresponding to different scanning methods, that is, sector and linear scan. For this purpose, simplified stud bolt specimens with artificial defects of various depths were prepared.
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Authors: Sinan Fidan, Tamer Sınmazcelik, Egemen Avcu, Mustafa Ozgur Bora, Onur Coban
Abstract: This paper utilizes the micro computerized tomography (micro-CT) as the NDI technique to characterize the initial matrix delaminations locations and sizes in an aramid/glass fiber reinforced hybrid composite test specimen after a low velocity impact tests. Further, to visualize the localized low velocity impact damage volumes; based on the specimens micro-CT results; image analysis, geometric modeling and meshing softwares CtAn and CtVox were used. Finally, interpretation of damage mechanisms occurred in aramid/glass fiber reinforced hybrid composite after low velocity impact loading presented with accurate 3-D rendered models obtained from a series of micro-CT slices. 3-D rendered models gained from impacted specimens help to quantify the internal microscopic damage modes of complex material system such as aramid/glass fiber reinforced hybrid composite. It is very important to predict or determine composite materials response to an impact loading since impacts occur during manufacture, normal operations, maintenance, etc. After low velocity impact loading tests, investigation of damage zone will provide a better composite manufacturing process. For example, it is acknowledged that up to 80% of the cost of manufacture of a composite is xed once the preliminary conguration had been nalised. Further detail changes afterwards can only make a small impact on the nal cost of the manufacturing process.
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Authors: Ryo Ito, Takayuki Azuma, Tomoyuki Kasuga, Shinji Soma, Shinji Murakami, Tunemoto Kuriyagawa
Abstract: This study was performed to develop a non-destructive inspection system to detect grinding burn, which is capable of quantitative 100% inspection inside a production line. An eddy current sensor, which has advantages of short inspection time and low cost, was used. It was shown that the grinding burn detection technique had been developed and is possible to detect grinding burn by using this technique, in the 1st report1) and the 2nd report2). In this report, we have attempted to apply the grinding burn detection technique to evaluate the residual stress of work piece surface. Residual stress of work piece surface is affected by both thermal and mechanical effects. It is shown that the residual stress is possibly evaluated in the case of the thermal effect is dominant.
307
Authors: Ryo Ito, Naomasa Mukaide, Takayuki Azuma, Shinji Soma, Shinji Murakami, Tunemoto Kuriyagawa
Abstract: This study was performed to develop a non-destructive inspection system to detect grinding burn, which is capable of quantitative 100% inspection inside a production line. An eddy current sensor, which has advantages of short inspection time and low cost, was used. It was shown that the grinding burn detection technique had been developed and is possible to detect grinding burn by using this technique, in the 1st report1) and the 2nd report2). In this report, an experiment of in-process detection of grinding burn was conducted, by applying the grinding burn detection technique which we have developed. The eddy current sensor has been combined with an in-process gauge in order to keep the clearance between the sensor probe and the work piece constant. It was shown that grinding burn can be detected successfully during cylindrical machining.
135
Authors: Toshimitsu Baba, Kazuhiro Ogawa, Tetsuo Shoji
Abstract: A novel non-destructive inspection (NDI) technique that utilizes high-frequency signal transmission characteristics was developed as a more reliable, faster and cheaper NDI technique. This technique forms a transmission circuit that includes the specimen, and detects the signals generated by any surface breaking-defect. In this research, quantitative measurement of closed fatigue cracks was implemented via a newly developed probe. The greatest advantage of this technique is that there is no significant difference in detection of defects in either paramagnetic materials or in ferromagnetic materials. Therefore, the potential effects of corrosion, ferrite content, or deformation martensite on the measurement signals are minimized, and a better S/N ratio can be expected. This technique can also be used to measure the size of defects in components, including welded components, and its detection sensitivity is less than 1 mm for surface breaking-defects.
949
Authors: Alan Jiang
Abstract: The concretes non-destructive inspection technology take does not harm the concretes component's operational performance as the premise, the application many kinds of physics principles and the chemical phenomenon, carries on the effective examination and the test to the structural element, in order to appraises their continuity, the integrity, the security reliability and certain physical property, including is examined in the material and the component whether to have the flaw, and to the flaw shape, the size, the position, the orientation, the distribution and situations and so on content carries on the judgment. The acoustic emission technology is one kind of dynamic non-destructive inspection technology, moreover sound transmitting message from flaw itself, therefore, may judge the flaw with the sofar efflux the gravity. A similar size, uniform quality flaw, when they receive the stress condition and locates when the position is different, is also different to the structure extent of damage, therefore their acoustic emission characteristic also has the difference.
517
Authors: Hiroyuki Kisu, Gui Ming Rong
Abstract: This paper will propose an identification algorithm for a small defect in the case of the bending problem of a beam. That is to say, the part where a defect exists is replaced by an equivalent load term. It shows that the defect can be accurately identified even there is observation error if the problem of identifying a defect is converted to that of identifying a load.
2441
Authors: Kyung Seok Song, Jae Yeol Kim, You Hong Kim
Abstract: Contact type detection, one of UT for the detection of defects in welding area, has several weak-points. Proximity type ultrasonic inspection using laser is being studied these days to make up for the weak points of contact type ultrasonic inspection. In this paper, automatic inspection system of the welding area of spiral welding pipe has been developed, of which mechanical characteristic is better than that of circular directional pipes, and executed the proximity ultrasonic inspections using laser. The usefulness of proximity ultrasonic inspection using laser will be verified in this paper through the analysis of the inspection results.
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