Mixed Experimental‐Structural Model for Interlaminar Shear Fracture Toughness
Publication: Journal of Aerospace Engineering
Volume 4, Issue 1
Abstract
For brittle composite materials, a mixed experimental and structural model is developed to determine a consistent interlaminar shear fracture toughness in an end notched flexure (ENF) test. The ENF procedure presented here differs from the customary ENF test in that one specimen is used for multiple measurements of compliances and the corresponding critical loads and crack growths; this procedure reduces the number of specimens needed to determine Using this test procedure, is difficult to compute from only the experimental results because the critical load is sensitive to the inhomogeneity of the material and the specimen variation; thus a model that integrates the experimental results with structural beam theory is developed. Using the experimental results, a functional relationship between the critical load and the important geometric and material properties is obtained. A structural model is developed from Castigliano's second theorem to compute the flexural and transverse shear deflection of the delaminated beam. Experimental results are presented for three 32‐ply multidirectional graphite‐epoxy laminates: and ldquo; The structural model is compared with the experimental compliance and deflection results, and is determined using the experimental and structural model. obtained by this experimental procedure is compared to the determined using the customary ENF test procedure.
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References
1.
ASTM meeting minutes. (1988). ASTM D30.02.02 Task Group on Interlaminar Fracture Toughness, ASTM, Philadelphia, Pa., Apr. 26.
2.
Carlsson, L. A., Gillespie, J. W., and Pipes, R. B. (1986). “On the analysis and design of the end notched flexure (ENF) specimen for mode II testing.” J. Composite Mat., 20, Nov., 594–604.
3.
Mall, S., and Kochhar, N. K. (1986). “Finite‐element analysis of end‐notch flexure specimens.” J. Composites Tech. and Res., 8(2), 54–57.
4.
Murri, G. B., and Guynn, E. G. (1986). “Analysis of delamination growth from matrix cracks in laminates subjected to bending loads.” NASA Technical Memorandum 87754, Nat. Aeronautics and Space Admin., Langley, Va., Jul.
5.
Murthy, P. L. N., and Chamis, C. C. (1985). “Interlaminar fracture toughness ee‐dimensional finite element modeling of end‐notched flexure.” NASA Technical Memorandum 87138, Nat. Aeronautics and Space Admin., Lewis Space Ctr., Ohio.
6.
Murthy, P. L. N., and Chamis, C. C. (1986). “Composite interlaminar fracture toughness: 3‐D finite element modeling for mixed mode I, II, III fracture.” NASA Technical Memorandum 88872, Nat. Aeronautics and Space Admin., Lewis Space Ctr., Ohio.
7.
Russell, A. J. (1982). “On the measurement of mode II interlaminar fracture energies.” Materials Report 82‐0, Defence Res. Establishment Pacific, Victoria, British Columbia, Canada.
8.
Russell, A. J. (1987). “Micromechanisms of interlaminar fracture and fatigue.” Polymer Composites, 8(5), 342–352.
9.
Spiegel, M. B. (1961). Schaum's outline series theory and practice: Statistics. McGraw‐Hill, New York, N.Y., 243–244.
10.
Whitney, J. M., Browning, C. E., and Mair, A. (1974). “Analysis of the flexure test for laminated composite materials.” Composite Materials Testing and Design (ASTM STP 546), Am. Soc. for Testing and Materials, Philadelphia, Pa., 30–45.
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Copyright © 1991 ASCE.
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Published online: Jan 1, 1991
Published in print: Jan 1991
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