1998 Fiscal Year Final Research Report Summary
Dynamic Fracture Mechanics Study on the Shear Failure Mechanism of Reinforced Concreate Members subjected to Inpact Forces
| Project/Area Number |
09450208
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Building structures/materials
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| Research Institution | Kyoto University |
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Principal Investigator |
TOMINAGA Megumi Kyoto University, Faculty of Engineering, Assoc. Professor, 工学研究科, 助教授 (90025924)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Reinforced Concreate Member / Impact Testing / Shear Failure / Failure Modes / Fracture Mechanics / Wave Propagation / Numerical Analysis / Markov Process |
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| Research Abstract |
1. Based on the theory of rate processes in the kinetics of chemical reaction, a stochastic process theory for the fracture of solid bodies is applied for the shear fracture problems of reinforced concrete members.
2. The distribution functions of the shear fracture probabilities are theoretically obtained, including both the velosity effects of applied shear force and failure zone sizes, for the two different modes of the flexural shear fracture and the bond-shear splitting one. It is shown that the larger amount of failure probability leads to the corresponding mode of shear fracture, depending on the magnitudes of shear force velosity.
3. A series of experimental studies on the shear failure mechanism of the reinforced concrete cantilever beams with some different shear-span ratios and crack-like notches were carried out under impact loading applied at the free end. Detailed and elaborate measuring instruments for CMOD in both vertical and longitudinal directions, diagonal shear crack development rate, strain distribution of steel and concrete and acceleration at some points were employed in the tests. As the results, some important findings on the mechanism development of the beams under high speed loadings were obtained.
4. From numerical analysis based on the LSDYNA program, wave propagation behaviour of the beams after the impacts were simulated. Effect to the successive development of main shear crack due to every applied impact increment, in energy bases, were investigated.
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