1992 Fiscal Year Final Research Report Summary
Study on the Brittle Fracture of Welded Beam-to-Column Connections of Heavy Steel
| Project/Area Number |
03650471
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Building structures/materials
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| Research Institution | Faculty of Engineering, Fukuyama University |
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Principal Investigator |
NAKAYAMA Akio Fukuyama University, Department of Architecture, Professor, 工学部, 教授 (70026235)
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| Co-Investigator(Kenkyū-buntansha) |
KUWADA Hirotsugu Fukuyama University, Department of Architecture, Research Assistant, 工学部, 助手 (60161808)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Brittle Fracture / Notch Toughness / Crack Tip Opening Displacement / Plane Strain / Plastic Constraint / Heavy Steel |
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| Research Abstract |
It was reported that the brittle fracture in plastic range took place at room temperature in the full scale tests of wide flange beam-to-column connections of heavy steel. We considered this was caused by the plastic constraint, that is, constraint intensity of plastic deformation mainly. The brittle fracuture is caused under the condition of plane strain and this condition of plane strain is satisfied when the Young's modulus or the yield stress is very large, or the dimension of specimen is huge. The Young's modulus and yield stress are not so large unless the temperature becomes extremely low like -100ﾟC. Therefore we carried out the CTDO testing of heavy steel using the specimen which has B/W (B and W are the width and height of specimen ) from 0.5 to 5. As the result, when B/W ratio is about 5, even in the room temperature the brittle fracture takes place and the lateral shrinkage ratio becomes almost 0, so the condition of plane strain is satisfied.
As a next stage, we carried out the tension test of weld specimen using heavy steel of 40 mm thickness and confirmed the specimen in the state of plane strain and the weld specimens fractured brittlely.
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