E. I. duPont de Nemours & Co., Wilmington, Del.
Pages: 33 Published: Jan 1973
The emergence of advanced filamentary composite materials as a structural material comes at a time of increasing concern over reliability. This places increasing emphasis on the ability to characterize the fracture and fatigue behavior of these materials. The importance of understanding fracture behavior is intensified because of the characteristic statistical variability in material strength and the observation of fracture phenomena that are significantly different from those of metals. This paper discusses what appear to be the three main approaches being pursued. The first applies classical fracture mechanics (CFM) on a macroscopic level, treating composites as homogeneous, anisotropic materials. The second recognizes material heterogeneity and applies CFM to the problems of crack propagation in the matrix and fiber phases and interfaces separately. The third method, which might be called the material modeling approach, uses approximate models in order to represent the major effects of heterogeneity and simplify the analysis. The advantages and limitations of each of the three approaches are discussed and predictions compared with available experimental data. The emphasis is on material modeling, and it is shown that with the use of relatively simple models it is possible to predict many of the unusual fracture phenomena that are observed.
composite materials, fracture strength, crack propagation, fibers, laminates, cyclic loads, failure, fatigue (materials)
Paper ID: STP36480S