Evaluation of Rib/Skin Fracture in Composite Isogrid
Publication: Journal of Engineering Mechanics
Volume 123, Issue 1
Abstract
Fracture mechanics was used to evaluate failure of the rib/skin connection of composite “isogrids.” The energy derivative method was used to determine the strain energy release rate (G) using a general purpose finite-element (FEM) program with an orthotropic material model. Flexure tests were conducted to observe when rib/skin interface fractures propagate, and the results were correlated with the FEM-based fracture mechanics model. A laser interferometry technique, electronic shearography was used to monitor crack propagation during the flexure tests. Environmental scanning electron microscopy (ESEM) was used to understand the micromechanical aspects of fracture. Variation of the fiber volume fraction, rib thickness, and the presence of weak shear zones were found to be critical to the failure process. The paper explores the concepts of linear elastic and nonlinear fracture as applicable to these graphite/epoxy composite structures. This study provides the designers and users of the isogrid with a methodology for quantifying structural degradation as a function of the rib/skin disbond.
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References
1.
Ambur, D. R., and Rehfield, L. W. (1991). “Effect of stiffness characteristics on the response of composite grid-stiffened structures.”AIAA Paper No. 91-1087-CP, Am. Inst. of Aeronautics and Astronautics, Washington, D.C.
2.
Ashton, L. J., Huntsman, S. D., Allman, M. G., Strong, A. B., and Rotz, C. A. (1991). “Filament winding of composite isogrid fuselage structures.”Publ., Soc. of Manufacturing Engrs., Dearborn, Mich.
3.
Bunakov, V. A., and Protasov, V. D. (1989). Cylindrical reticular composite shells. Plenum Publishing Corp., New York, N.Y., 759–766.
4.
Chang, S. G., and Mar, J. W. (1984). “The catastrophic failure of pressurized graphite/epoxy cylinders initiated by slits at various angles.”AIAA Paper No. 84-0887, Am. Inst. of Aeronautics and Astronautics, 123–129.
5.
Daniel, I. M., and Ishai, O. (1994). Engineering mechanics of composite materials. Oxford University Press, New York, N.Y.
6.
Fleck, N., Hutchinson, J. W., and Sou, Z.(1991). “Crack path selection in a brittle adhesive layer.”Int. J. Solids Struct., 27(13), 1683–1703.
7.
Ginty, C. A., and Chamis, C. C. (1994). “Select fiber composites for space applications: a mechanistic assessment.”NASA Tech. Memo. TM 83631, NASA, Washington, D.C.
8.
Gurdal, Z., and Grall, B.(1994). “Buckling analysis of geodesically stiffened composite panels with discrete stiffeners.”J. Aircraft, 31(5), 1197–1204.
9.
Hung, Y. Y.(1982). “Shearography: a new optical method for strain mesurement and nondestructive testing.”Optical Engrg., 21(3), 391–395.
10.
Hung, Y. Y.(1989). “Shearography: a novel and practical approach for nondestructive inspection.”J. Nondestructive Evaluation, 8(2), 55–67.
11.
“I-DEAS.” (1993). Structural Dynamics Research Corporation, Milford, Ohio.
12.
Kam, C. Y., Freeman, V. L., and Penon, A. P. (1978). “Stiffened composite structural member and method of fabrication.” U.S. Patent No. 4,086,378. U.S. Patent Ofc., Washington, D.C.
13.
Koury, J. L., Kim, T. D., Tracy, J. J., and Harvey, J. A. (1993). “Continuous fiber composite isogrid structures for space applications.”Proc., ASM Conf., Am. Soc. for Metals, Internation Metals Park, Ohio.
14.
Lemaitre, J., and Chaboche, J. L. (1991). “Crack mechanics.”Mechanics of solid materials, Cambridge University Press, New York, N.Y., 451–549.
15.
Mukherjee, A. K. (1989). “Isogrid shell in aerospace structures.”IE(I) J., 69(Sep.–Mar.), 6–9.
16.
NASA. (1973). Report No. CR124075. Washington, D.C.
17.
NASA. (1995). Tech. Memo. TM X 72771. Washington, D.C.
18.
Newman, J.(1991). “Shearographic inspection of aircraft structure.”Mat. Evaluation, 49(9), 1106–1109.
19.
Parks, D. M.(1974). “A stiffness derivative finite element technique for determination of crack-tip stress intensity factors.”Int. J. Fracture, 10, 487–502.
20.
Reddy, A. D., Rehfield, L. W., Haag, R. S., and Widman, C. G. (1983). “Compressive buckling behavior of graphite/epoxy isogrid wide columns with progressive damage.”ASTM STP 808, R. Chait and R. Papirno, eds., ASTM, Philadelphia, Pa., 187–199.
21.
Reddy, A. D., Rao, V. R., and Rehfield, L. W.(1985). “Continuous filament wound composite concepts for aircraft fuselage structures.”J. Aircraft, 22(3), 249–255.
22.
Rehfield, L. W. (1982). “Studies of advanced and composite structures.”AFOSR Rep. No. 82–1016, Air Force Ofc. of Scientific Res.
23.
Rhodes, M., and Mikulas, M. M. (1975). “Composite lattice structures.”NASA Tech. Memo. TM X-72771, NASA, Washington, D.C.
24.
Rice, J. R. (1988). “Elastic fracture mechanics concepts for interfacial cracks.”Trans. ASME, 55(Mar.), 98–103.
25.
Slysh, P., Dyer, J. E., Furman, J. H., and Key, J. E. (1975). “Isogrid structures.”AIAA Paper No., Am. Inst. of Aeronautics and Astronautics, Washington, D.C., 75–816.
26.
Tada, H., Paris, P. C., and Irwin, G. R. (1973). The stress analysis of cracks handbook. Del Research Corp., Hellertown, Pa.
27.
Tomshevskii, V. T., Kalinin, V. N., and Yakivlev, V. S. (1989). Optimization of composite shells of revolution with a mixed system of reinforced elements. Plenum Publishing Corp., New York, N.Y., 1054–1059.
28.
Williams, M. L.(1959). “The stresses around a fault or crack in a dissimilar material.”Bull. Seismological Soc. of Am., 49(2), 199–204.
Information & Authors
Information
Published In
Journal of Engineering Mechanics
Volume 123 • Issue 1 • January 1997
Pages: 83 - 90
Copyright
Copyright © 1997 American Society of Civil Engineers.
History
Published online: Jan 1, 1997
Published in print: Jan 1997
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