Composite materials, characterization fracture

Whitney, J.M. (1989). Experimental Characterization of delamination fracture, in Interlaminar Response of Composite Materials (N.J. Pagano ed.), Elsevier Science Publishers, Amsterdam, pp. 161-250. 

Alexander, R.M., Schapery, R.A., Jerina, K.L. and Sander, B.A. (1982). Fracture Characterization of a random fiber composite material. In Short Fiber Reinforced Composite Materials. ASTM STP 722 (B.A. Sanders cd.), ASTM, Philadelphia, PA, pp. 208-224. 

J. Souza, Fracture Mechanics Characterization of WPC-FRP Composite Materials Fabricated by the Composites Pressure Resin Infusion System (Compris) Process Volume... 

Work of fracture is considerably increased when a brittle matrix is reinforced by a system of inclusions in the form of grains or fibres. An internal structure created purposefully transforms a brittle behaviour into a quasi-ductile one, characterized by large deformations and high fracture toughness. This transformation into a composite material is described here on many occasions. 

There are three main types of failure by crack propagation as shown in Figure 10.3 1 (opening), II (sliding), and III (tearing). In real elements made with composite materials and subjected to external load, all modes appear in different combinations and it is not completely clear how to deal with that situation. The models proposed at present seem to still be dependent on the scale if in macro scale the tests executed according to these three modes are possible the obtained results characterize only the effects in the same scale with mean values of some correcting parameters. On lower scales probably all modes appear simultaneously or at least Modes I and II act conjointly. The mixed-mode fracture parameters may be calculated for linear elastic materials within the frames of LEFM, but their direct application to the cement-based composites is questioned. The considerations below are partly based on the paper by Brandt and Prokopski (1990). 

The SIFCON elements exhibit a considerable increase in strength and ductility compared to ordinary fibre reinforced concrete. The fracture toughness, calculated as proportional to the area under load-deflection curves, was also increased and the curves were characterized by a post-peak plateau. After these tests, it was concluded that the quality of the matrix itself contributed significantly to the overall behaviour of the composite material. That effect was studied further by Shah (1991) who showed an increased strain and strength capacity for a matrix subjected to tension. Therefore, these results confirmed earlier achievements in SIFCON technology and also supported... 

Elsevier-Applied Science Publishers have recently begun to publish a Developments in... series. The separate topics covered are adhesives, composite materials, injection moulding, polymer characterization, polymer degradation, polymer fracture, polymer photochemistry, polymer stabilization, polyurethanes, PVC (production and processing), reinforced plastics, rubber and rubber composites, and rubber technology. 

Schapery R (1987) Deformation and fracture characterization of inelastic composite materials using potentials. Polymer Eng Sci 27 63-76... 

The two main approaches for dealing with the mechanics of asbestos-cement composites are based on composite materials concepts (rule of mixtures) and fracture mechanics, Microstructural characterization of the composite has usually been carried out in conjunction with these studies, to determine the numerical parameters required for the modelling, such as the aspect ratio, and to resolve the pull-out and fracture processes during failure. The results of these microstructural studies wi II be reviewed first, since they provide the background required for the modelling of the processes which control the mechanical performance of the hardened composite,... 

O Brien, T.K., Johnston, W.M., Toland, G.J., 2010. Mode II Interlaminar Fracture Toughness and Fatigue Characterization of Graphite Epoxy Composite Material. Report Prepared for NASA, NASA/TM-2010—216838, Hampton, Virginia. 

Composite interfaces exist in a variety of forms of differing materials. A convenient way to characterize composite interfaces embedded within the bulk material is to analyze the surfaces of the composite constituents before they are combined together, or the surfaces created by fracture. Surface layers represent only a small portion of the total volume of bulk material. The structure and composition of the local surface often differ from the bulk material, yet they can provide critical information in predicting the overall properties and performance. The basic unknown parameters in physico-chemical surface analysis are the chemical composition, depth, purity and the distribution of specific constituents and their atomic/microscopic structures, which constitute the interfaces. Many factors such as process variables, contaminants, surface treatments and exposure to environmental conditions must be considered in the analysis. 

The failure processes in thermoplastics composites with aligned glass fibers of sub-critical transfer length have been characterized (Lauke and Schultrich, 1983, 1986a, b Lauke et al., 1985 Lauke and Pompe, 1988) in terms of matrix fracture mode which is determined mainly by the ductility of the matrix material, loading rate and temperature. The total specific work of fracture, / t, is expressed as the sum... 

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