2002 Fiscal Year Final Research Report Summary
Elastic-plastic deformation of lightweight core-perforated sheet metal laminates and their optimum design considering strength, rigidity and formability
| Project/Area Number |
12555029
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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 | 展開研究 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
YOSHIDA Fusahito Hiroshima University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (50016797)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIYAMA Seiji Research Institute of Technology, Sumitomo Metals, Co. Ltd., Research Manager, 総合技術研究所, 研究部長
ISHIDA Kyosou Research Institute of Technology, Mazda Motor Co. Ltd., Research Engineer, 技術研究所, 主任研究員
HINO Ryutaro Hiroshima University, Graduate School of Engineering, Research Associate, 大学院・工学研究科, 助手 (10283160)
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| Project Period (FY) |
2000 – 2002
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| Keywords | perforated sheet / sheet metal laminate / lightweight / rigidity / strength / elasto-plasticity / optimum design / press-formability |
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| Research Abstract |
In this project, sandwiched metal plates with perforated core and skins are newly developed for the use of lightweight shell constructions. Using copper sandwiched specimens, mechanical properties of elasto-plasticity of this type of plates were examined by performing several mechanical tests such as uniaxial tension, bending and stretch forming. Moreover, the mechanisms of elastic-plastic deformation and the forming limit of this plate were investigated by the finite element analysis. The present findings are summarized as follows:
(1) The plastic-flow strength of the sandwiched plate (its volume fraction of voids V_f = 17%), as well as a monolithic copper sheet and a single perforated sheet (V_f = 28 were examined by uniaxial tension tests. For the single perforated sheet the specific strength (= strength divided by the density of the plates) is 28% less than that of the monolithic sheet, while for the sandwich plate it is only 5% less. The sandwich plate has excellent performance in bending rigidity, namely it is as high as 2.7 times of one of the monolithic plate.
(2) The forming limit diagram (FLD) of the sandwiched plate is similar to one of the single perforated sheet. The limit strain under plane-strain condition is not so small compared to one of the monolithic sheet, while it under balanced biaxial stretching condition is significantly smaller than that under uniaxial tension. From the experimental observations, as well as the FE simulation, it is concluded that the fracture of the sandwich plate will occur as a result of strain localization at the skin metals.
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