Development of Techniques Searching Damaged Locations and Evaluating their Damage Levels in Concrete Structures Through AE Wave Monitoring
| Project/Area Number |
59850076
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
土木構造
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| Research Institution | Tohoku University |
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Principal Investigator |
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| Project Period (FY) |
1984 – 1985
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| Project Status |
Completed (Fiscal Year 1985)
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| Budget Amount *help |
¥7,600,000 (Direct Cost: ¥7,600,000)
Fiscal Year 1985: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1984: ¥6,800,000 (Direct Cost: ¥6,800,000)
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| Keywords | concrete structure / damaged location / damage level / acoustic emission / AE source location / Kaiser effect / AE energy / AEエネルギー |
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| Research Abstract |
Various researches were carried out in order to search damaged locations and to evaluate their damage levels through the AE wave monitoring and the main results were explained belows.
(1) The Kaiser effect in the uniaxial compression tests of concrete specimens, the splitting tests of them, the same tests for the cores cut out of concrete and reinforced concrete beams and the bending tests of reinforced concrete beams were examined. Except the uniaxial compression and splitting tests for the cores, the maximum past loads in the specimens and beams were evaluated with sufficient accuracy for engineering. In addition, it was clarified that in the uniaxial compression tests of cubic concrete specimens and the splitting tests of cylindrical ones, the Kaiser effect in different loading directions was independent one another and this effect was remarkably affected by the method keeping concrete specimens.
(2) Through researches to evaluate the damage levels in concrete from the information of AE waves, it was shown that the change of AE energy distribution with increasing load was closely related to the microfracture mechanisms and AE activity factors, which were defined by the logarithm of AE energy per unit inelastic lateral strain, had close relation to the strength of concrete specimens and the past damage in them. Further, the relation between lateral strain and AE cumulative event count and the evaluation of AE sources from frequency spectra were researched.
(3) In order to search damaged locations in concrete, the monitoring system for three dimensional AE source location, which was equiped with the softwares trasmitting AE waves from six transient memory units to a fixed disk unit and determing arrival times of AE waves automatically, was developed. By use of this system, the three dimensional AE source location was carried out in concrete specimens and AE sources in the region surrounded by six transducers were located within error of distance 1 cm.
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Report
(1 results)
Research Products
(10 results)
