Journal of the Korean Society for Aviation and Aeronautics (한국항공운항학회지)

The Korean Society for Aviation and Aeronautics (한국항공운항학회)
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Predicting the Compressive Strength of Thin-walled Composite Structure

복합재 박막 구조물의 압축강도 예측

  • Received : 2019.06.05
  • Accepted : 2019.06.25
  • Published : 2019.06.30
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Abstract

The initial buckling of thin walled structures does not result in immediate failure. This post buckling capability is used to achieve light weight design, and final failure of thin walled structure is called crippling. To predict the failure load, empirical methods are often used for thin walled structures in design stage. But empirical method accuracy depend on geometry. In this study, experimental, empirical and numerical study of the crippling behavior of I-section beam made of carbon-epoxy are performed. The progressive failure analysis model to simulate the crippling failure is evaluated using the test results. In this study, commercial software LS-DYNA is utilized to compute the collapse load of composite specimen. Six kinds of specimens were tested in axial compression where correlation between analytical and experimental results has performed. From the results, we have partially conclude that the flange width-to-thickness ratio is found to influence the accuracy of empirical and numerical method.

Keywords

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Fig 1. Form of local buckling of various section

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Fig 2. Typical load displacement behavior of a thin plate

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Fig 3. Normalized crippling data for the no edge free case [4]

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Fig 4. Normalized crippling data for the one edge free case [4]

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Fig 5. Crippling analysis procedure

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Fig 6. Specimen configuration and size

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Fig 7. Force-displacement curve for A1 specimen

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Fig 8. Force-displacement curve for A2 specimen

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Fig 9. Force-displacement curve for A3 specimen

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Fig 10. Force-displacement curve for B1 specimen

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Fig 11. Force-displacement curve for B2 specimen

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Fig 12. Force-displacement curve for B3 specimen

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Fig 13. Crippling strength v.s. L/t for A1∼A3 specimens

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Fig 14. Crippling strength v.s. L/t for B1∼B3 specimens

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Fig 15. Comparison of crippling strength between test and empirical equation for A1∼A3 specimens

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Fig 16. Comparison of crippling strength between test and empirical equation for B1∼B3 specims

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Fig 17. Comparison of failure mode between test and numerical model

Table 1. T700G/2510 laminate properties

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Table 2. Comparison of crippling strength between least square fit and preliminary design curve

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Table 3. Material properties of CFRP lamina

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Table 4. Layup pattern and dimension

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Table 5. Summary of test and numerical analysis results

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References

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  3. T. Von Karman, and E. Sechler, "The strength of thin plates in compression," ASTM Appl Mech Trans, Vol. 54, 1932, pp. 53-57
  4. MIL-HDBK-17H, Composite Materials Handbook
  5. AGATE-WP3.3-033051-135, A-basis and B-basis design allowables for epoxy - based prepreg
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