1995 Fiscal Year Final Research Report Summary
A Study on High Velocity Fracture of Materials Induced by Explosive Shock Loading
| Project/Area Number |
06651099
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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 |
資源開発工学
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| Research Institution | Kumamoto University |
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Principal Investigator |
HIROE Tetsuyuki Kumamoto Univ., Faculty of Eng., Professor, 工学部, 教授 (90218826)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIWARA Kazuhito Kumamoto Univ., Faculty of Eng., Lecturer, 工学部, 講師 (50219060)
MATSUO Hideo Kumamoto Univ., Faculty of Eng., Professor, 工学部, 教授 (00040395)
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| Project Period (FY) |
1994 – 1995
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| Keywords | lmpact Strength / Spall / Fracture Criterion / Stress Wave / Finite Differencl Method / Plane Detonation / Wire Explosion / Explosive Loading |
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| Research Abstract |
Testing apparatus for spalling phenomena of materials induced by plane detonation waves has been developed using the wire-row explosion technique. This test assembly for direct explosive loading can generate one-dimensional triangular stress waves with various gradient and peak values in plate specimens (50x50x20mm) by varying the thicknesses (5-15mm) of explosive (PETN). Spall tests are conducted for three kinds of materials (aluminum alloy A12024, carbon steel JIS SS41 and pure copper) and spallation or scab has been observed within the undisturbed region in the cross section of every recovered specimen. The relation of measured spall layr thicknesses and PETN thicknesses indicate that the strong time-dependency exists in spall phenomena of the tested metals, especially A12024. Thesd results can not be produced by idealizes representation of a triangular stress pulse.
A computer code of one-dimensional finite difference method is constructed in cooperative with the cumulative damage model for time-dependency, and it has reproduced the basic characteristics of the observed failure in the metals after trial-and-error selection of constants for the damage model. The code has been applied also to the numerical simulation of plate impact test successfully.
It is known that the stress wave reflected at the free surface can be prevented from reaching the specimen plate by spallation of the momentum trap or spall plate, which is mounted in contact with the apecimen. The following spall test results for A12024 have verified this effect, and the numerical analysis also has simulated the phenomena successfully.
The experimental technique used here also has been applied to generate the cylindrical imploding shocks in solids and it can produce the cylindrical exploding shocks.The failure problems induced by these shocks are left unsolved.
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Research Products
(12 results)
