Predicting viscoelastic response and delayed failures in general laminated compositesAlthough graphite fibers behave in an essentially elastic manner, the polymeric matrix of graphite/epoxy composites is a viscoelastic material which exhibits creep and delayed failures. The creep process is quite slow at room temperature, but may be accelerated by higher temperatures, moisture absorption, and other factors. Techniques are being studied to predict long-term behavior of general laminates based on short-term observations of the unidirectional material at elevated temperatures. A preliminary numerical procedure based on lamination theory is developed for predicting creep and delayed failures in laminated composites. A modification of the Findley nonlinear power law is used to model the constitutive behavior of a lamina. An adaptation of the Tsai-Hill failure criterion is used to predict the time-dependent strength of a lamina. Predicted creep and delayed failure results are compared with typical experimental data.
Document ID
19840044565
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Dillard, D. A. (Missouri-Rolla, University Rolla, MO, United States)
Morris, D. H. (Missouri Univ. Rolla, MO, United States)
Brinson, H. F. (Virginia Polytechnic Institute and State University Blacksburg, VA, United States)