Fracture fundamentals

Fracture Fundamentals, High-Temperature Deformation, Damage,... 

BRA 92] BRADT R.C., HASSELMAN D.P.H., MUNZ D., SAKAI M. and SHEVCHENKO V.Y., Fracture mechanics of ceramics, vol. 10, Fracture fundamentals, high temperature deformation, damage, and design. Plenum Press, New-York and London, 1992. 

J. F. Knott, fundamentals of fracture Mechanics, Butterworths, London, 1979. 

The one-dimensional geometry of a radially expanding ring is perhaps the simplest for considering fundamental aspects of the fracture and fragmentation process. In a ductile metal ring, fracture proceeds through the multiple... 

Orowan, E. (1952) Fundamentals of brittle behavior in metals, in Fatigue and Fracture of Metals, Symposium at MIT, ed. Murray, W.M. (MIT and Wiley, New York). 

This is a very important relationship in that it permits the fundamental material property Gc to be calculated from the fracture force, Fc, and the variation of compliance with crack length. 

If the matrix is assumed to have the same strain in the fiber direction as the fiber (the fundamental approximation for strains in the determination of Ei in Section 3.2.1, which is reasonable if no fractures occur), then... 

The fundamental analysis of a laminate can be explained, in principle, by use of a simple two-layered cross-ply laminate (a layer with fibers at 0° to the x-direction on top of an equal-thickness layer with fibers at 90° to the x-direction). We will analyze this laminate approximately by considering what conditions the two unbonded layers in Figure 4-3 must satisfy in order for the two layers to be bonded to form a laminate. Imagine that the layers are separate but are subjected to a load in the x-direction. The force is divided between the two layers such that the x-direction deformation of each layer is identical. That is, the laminae in a laminate must deform alike along the interface between the layers or else fracture must existl Accordingly, deformation compatibility of layers is a requirement for a laminate. Because of the equal x-direction deformation of each layer, the top (0°) layer has the most x-direction ress because it is stiffer than the bottom (90°) layer in the x-direction./ Trie x-direction stresses in the top and bottom layers can be shown to have the relation... 

It seems that indeed the answers to many fundamental questions are obtained, at least in qualitative form. Perhaps, the most important exception are thixotropic phenomena. There are many of them and the necessary systematization and mathematical generalization are absent here. Thus, it is not clear how to describe the effect of an amplitude on nonlinear dynamic properties. It is not clear what is the depth and kinetics of the processes of fracture-reduction of structure, formed by a filler during deformation. Further, there is no strict description of wall effects and a friction law for a wall slip is unknown in particular. 

The tensile curve of a polymer fibre is characterised by the yield strain and by the strain at fracture. Both correspond with particular values of the domain shear strain, viz. the shear yield strain j =fl2 with 0.04rotation angle of -0y=fl2 and the critical shear strain 0-0b=/iwith /f=0.1. For a more fundamental understanding of the tensile deformation of polymer fibres it will be highly interesting to learn more about the molecular phenomena associated with these shear strain values. 

Anderson, T. L. 1995. Fracture Mechanics Fundamentals and Applications. CRC Press, New York. 

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