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Abstract
The residual strength of an impacted composite laminate depends upon the extent and distribution of the damage through the thickness. This in turn is determined by the energy and velocity of impact, and other material and test parameters. In-plane compressive loading of the multi-layered composite laminates containing damage is considered to be highly critical since under such a condition the strength reduction is expected to be the largest. Hence, much of the effort in recent research has been directed towards understanding the behavior of impact-damaged laminates under compressive loading. One type of test that has been widely used to evaluate the residual mechanical properties of these laminates is the compression after impact (CAI). In this study, compression tests have been conducted as per NASA specifications on woven fabric Carbon Fiber Reinforced Plastic (CFRP) laminate specimens unimpacted and impacted at different energy levels. Strain gauges have been employed to ensure uniform, symmetric loading and to obtain the failure strain. In this paper, the test procedure foLlowed and the results obtained from CFRP laminates subjected to low velocity impact at three dffirent energy levels are discussed in detail.
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References
- Serge Abrate., "Impact on Laminated Composite Materials", ASME, Applied Mechanics Review, Yol.44, No.4, April 1991, pp.155-190.
- Serge Abrate., "Impact on Laminated Composites : Recent Advances", ASME , Applied Mechanics Review, Vol. 47, No. 11, November 1994, pp. 517 -543.
- Cantwell, W.J. and Morton, J., "The Impact Resistance of Composite Materials- A Review", Composites, Vol. 22, No. 5, September 1991, pp. 347-362.
- Prichard, J.C. and Hogg, P.J., "The Role of Impact Damage in Post Impact Compression Testing", Composites, Vol. 21, No. 6, November 1990, pp.503-511.
- Hosur, M.V. "Studies on Damage and Residual Compressive Strength of CFRP Laminates Subjected to Low-Velocity Impact", Ph.D. Thesis, Department of Aerospace Engineering, Indian Institute of Science, Bangalore, India, December I995.
- Bhat, M. R. "Evaluation of Impact Induced Damage and its Growth Under Fatigue in Woven Fabric Carbon Epoxy Laminates : An Approach , Ph.D. Thesis, Department of Aerospace Engineering, Indian Institute of Science, Bangalore, India, July 1998.
References
Serge Abrate., "Impact on Laminated Composite Materials", ASME, Applied Mechanics Review, Yol.44, No.4, April 1991, pp.155-190.
Serge Abrate., "Impact on Laminated Composites : Recent Advances", ASME , Applied Mechanics Review, Vol. 47, No. 11, November 1994, pp. 517 -543.
Cantwell, W.J. and Morton, J., "The Impact Resistance of Composite Materials- A Review", Composites, Vol. 22, No. 5, September 1991, pp. 347-362.
Prichard, J.C. and Hogg, P.J., "The Role of Impact Damage in Post Impact Compression Testing", Composites, Vol. 21, No. 6, November 1990, pp.503-511.
Hosur, M.V. "Studies on Damage and Residual Compressive Strength of CFRP Laminates Subjected to Low-Velocity Impact", Ph.D. Thesis, Department of Aerospace Engineering, Indian Institute of Science, Bangalore, India, December I995.
Bhat, M. R. "Evaluation of Impact Induced Damage and its Growth Under Fatigue in Woven Fabric Carbon Epoxy Laminates : An Approach , Ph.D. Thesis, Department of Aerospace Engineering, Indian Institute of Science, Bangalore, India, July 1998.