1994 Fiscal Year Final Research Report Summary
Bending and Torsional Rigidities of Circular Cylindrical Shells of Composite Materials under Beam-like Bending
| Project/Area Number |
04452109
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Aerospace engineering
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| Research Institution | University of Tsukuba |
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Principal Investigator |
KOGA Tatsuzo Univ.of Tsukukba, Vice President, 副学長 (60153508)
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| Project Period (FY) |
1992 – 1994
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| Keywords | composite materials / circular cylinder / buckling / collapse / 4-point bending / beam-like bending / bending rigidity / torsional rigidity |
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| Research Abstract |
The main objective of this research is to clarify the buckling strength of circular cylindrical shells of composite materials under beam-like pure bending. Fundamental characteristics of the mechanical behaviors of the circular cylindrical shells under beam-like pure bending is examined by conducting an extensive experiment on thin circular cylindrical shells of an isotropic elastic material. The experiment was conducted by using a high precision loading device which was designed so as to prevent the axial force and to realize the pure bending. The results indicate that the collapse of the cylinders is due to the buckling and that the critical load may be determined by the classical buckling stress of the circular cylindrical shells. Then, test specimens of circular cylindrical shell of composite materials were made of plastics reinforced by the glass fibers and the carbon fibers. They were tested by the method of the four-point bending using a conventional testing machine. The test results show a general trend which confirms the conclusion drawn from the test results on the isotropic shells, so that the collapse load may be predicted by the classical buckling stress if the material constants are available. An optical method has been proposed to measure the bending and torsional rigidities as well as Poisson's ratio of composite materials. It has been shown that the method is effective for the C/C composites as well as conventional laminates of fiber reinforced plastics.
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