Non-destructive testing technique was developed for embedded hardware using acoustic emission sensors. In this technique, AE sensor records the acoustic vibration generated by striking the embedded hardware with a hammer. The fixed state of the embedded hardware is judged from the vibration time of the embedded hardware recorded by the AE sensor and the frequency distribution of the acoustic signal. Mockup tests and FEM analysis were carried out in order to verify the effectiveness of the technique....
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Embedded hardware inspection using AE sensor Part1 Mockup tests

Fiber reinforced plastic (FRP) is used in a wide range of applications due to its light weight, high strength, excellent corrosion resistance and flexible processability. Although nuclear power plants may have a chance to use FRP as structural and equipment materials in the future, its radiation effect is not well known so far. Thus, we tried to evaluate its radiation degradation non-destructively using "AE (Acoustic Emission) digital hammering inspection". Two types of FRP test specimens of glass fiber and...
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Development of nondestructive inspection system for soundness diagnosis of FRP

On-site trial of a new technology of i-Construction was successfully carried out for the quality control of concrete construction through hammering inspection using AE sensor. In addition, some mockup tests showed that the inspection has a potential to identify several defects and compressive strength of concrete....
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On-site trial of a new technology of i-Construction: Quality control of concrete construction through hammering inspection using AE sensor

Insulation degradation of cable insulation causes fire due to electric leakage. Cable insulating materials laid in nuclear power plants deteriorate over time, heat and influence of radiation. Here we investigated the degradation tendency of insulating materials by radiation irradiation by hammering inspection using AE sensor. As a result, for any cable insulation material, curing of insulating material with irradiation could be detected as a change in natural frequency. From here, the applicability of AE ha...
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Development of nondestructive inspection system for soundness diagnosis of cable insulating material

We reported previously the deterioration tendency of cable insulation materials used in nuclear power plants due to irradiation and the applicability of AE (Acoustic Emission) digital hammering inspection to detect the deterioration nondestructively by comparing the natural frequencies before and after the irradiation. In this study, we selected two kinds of triple core cables which are often utilized in nuclear power plants. The natural peak frequency increased due to the increase of irradiation dose, and ...
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Development of nondestructive inspection system for soundness diagnosis of cable insulating material (2)

We have researched radiation-induced deterioration behaviors of cable insulation materials used in nuclear power plants and a nondestructive inspection method to detect the behaviors in our past reports. The deterioration was generated by electron beam irradiation simulating gamma-ray irradiation in the field. As a result, we found it possible to detect the deterioration by comparing the natural frequencies of the cables before and after the irradiation through our original digital hammering inspection tech...
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Development of nondestructive inspection system for soundness diagnosis of cable insulating material (3)

Abstract We developed a hammering sound inspecting system using AE sensor with objectivity and recordability and confirmed that it is possible to grasp the state of concrete (internal cavity and surface peeling) from the vibration analysis result obtained , And confirmed the usefulness of concrete health diagnosis using this system. ...
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Development of nondestructive inspection system for soundness diagnosis of concrete structure

In this paper, we discuss the results of application of “Integrated system of digital hammering inspection and digital visual inspection” to the detectability of flacking, cracks and backside cavities of the tunnel lining as well as flacking and backside cavities of concrete paving in a national highway tunnel....
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Development of diagnostic technology for concrete structures using digital hammering inspection

We have developed a simple diagnosis method using an AE (Acoustic Emission) sensor applicable to chemical anchors in nuclear power plants. With purpose of its application to the field, waveform database to identify improper installation or ageing was constructed. We also confirmed applicability of the diagnosis method to other types of anchor (e.g. anchor bolts, mechanical anchors). Details of development chronology are described in this paper. . ...
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Developing a simplified diagnosis method for anchor bolts

We have developed a simplified diagnosis method of hammering inspection using AE (Acoustic Emission) sensor applicable to chemical anchors in nuclear power plants. The database was created to identify improper installation and aging of the anchors. We have also confirmed its applicability to other types of anchor (e.g. anchor bolts, mechanical anchors). The details of development process are described in this paper....
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Developing a simplified diagnosis method for anchor bolts (2)