1988 Fiscal Year Final Research Report Summary
A Statistical Study on Evaluation for Defect and Deformation Capacity of Welded Connection
| Project/Area Number |
62850105
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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 |
Building structures/materials
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| Research Institution | Nagoya Institute of Technology |
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Principal Investigator |
ONO Tetsuro Nagoya Institute of Technology, Professor, 工学部, 教授 (30024300)
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| Co-Investigator(Kenkyū-buntansha) |
中川 進一郎 中部電力, 原子力土建課, 技士
IWATA Mamoru Nippon Steel Co., General Manager, 建築鉄構部, 部長代理 (50322532)
久保寺 勲 巴組鉄工所, 設計部, 部長
NAKAGAWA Shin-ichiro Chubu Electric Power Co., Chief Engineer
KUBODERA Isao Tomoegumi Iron Works Ltd., General Manager
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| Project Period (FY) |
1987 – 1988
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| Keywords | Welded Connection / Notch / Defective Member / Crack Openning Displacement / Fracture Mechanics / Beam-To-Column Connection / 柱-梁 接合部 / 塑性変形能力 / 確率論 |
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| Research Abstract |
The purposes of this project are to evaluate quantitatively the critical value of fracture of defective structural connection members on high strain region. In order to evaluate the deformation capacity of defective structure members which fracture after crack propagation in according with the COD criterion, the COD and the overall strain epsilon were measured using notched plate specimens. The relationship between COD and epsilon becomes almost linear after the specimens turn fully plastic. However, as the crack propagates, the increment of COD increases until the linear relationship disappears. The value of COD at this point is assumed as the critical value of crack propagation delta_c. It can be seen that the delta_c value for a particular type of steel is almost constant regardless of the size of specimens. Therefore, it is thought that delta_c is an effective critical value for fracture behavior of steel members.
Next, we evaluate the deformation capacity and the fracture behavior of notched plates by numerical analysis. The two-dimensional elasto-plastic analysis using the finite element method considering the effects of crack growth and plate thickness is devised. The COD and the J-integral based on the non-linear fracture mechanics are calculated, and further the relationships between the COD, the J-integral and the overall strain epsilon are investigated.
Next, we determine the critical value of fracture of defective structural members after crack propagation and thereby to measure quantitatively the fracture deformability of beam-column connections under cyclic loading. The results of experiments on defective connections are compared with those on notched plate specimens to obtain a relational expression of defect length, deflection amplitude, and hysteresis energy to fracture based on the COD concept in non-linear fracture mechanics.
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