Fracture behaviour

Occupational health advice as part of primary health care nursing The fracture behaviour of polyethylene - A literature review First aid retention of knowledge survey... 

Kinloch, A.J. and Young R.J. Fracture Behaviour of Polymers, Applied Science, London (1983)... 

Kinloch AJ, Young RJ (1983) Fracture behaviour of polymers. Applied Science Publishers, London... 

Whilst these extremes of behaviour can be readily distinguished, there are transitional types of fracture behaviour that lie between them, and in these cases, judgement about fracture mode can be difficult. 

Reiterer, A. and Sinn, G. (2002). Fracture behaviour of modified spruce wood a smdy using linear and non-linear fracture mechanics. Holzforschung, 56(2), 191-198. 

Harris B., Varlow J. and Ellis C.D. (1972). The fracture behaviour of fiber reinforced concrete. Cement Concrete Res. 2, 447-461. 

Karger-Kocsis J. and Friedrich K. (1988). Fracture behaviour of injection-molded short and long glass fiber-polyamide 6.6 composites. Composites Sci. Techno . 32, 293-325,... 

Lhymn C. and Schultz J.M. (1983). Fracture behaviour collimated thermoplastic poly(ethylene terephthalate) reinforced with short E-glass fiber. J. Mater. Sci. 18, 2029-2046. 

Daghyani, Fl.R, Ye. L. and Mai, Y.W. (1995a). Mode 1 fracture behaviour of adhesive joints, I, Relationship between fracture energy and bond thickness. J. Adhesion 53, 149-162. 

Most of the recent advances in the understanding of the fracture behaviour of epoxy polymers has been through the application of fracture mechanics 2) and the present Chapter is therefore concerned with the study of the mechanisms and mechanics of crack growth in crosslinked epoxies using fracture mechanics. 

The above observations enable a qualitative relation, based upon the role of crack tip blunting, to be postulated between the fracture behaviour and the viscoelastic yield behaviour of the materials1 8- 44,45). The basis for this relationship is the idea that crack-tip blunting decreases the local crack tip stress concentration and thus higher applied loads are required to cause failure. 

Hence, the ratio Klc/Klcs may be directly and quantitatively related to the crack tip radius, g, at the onset of crack growth by assuming a failure criterion based upon the attainment of a critical stress acting at a certain distance ahead of the tip. A brief examination of Eq. (12) shows that it exhibits the same general trends with regard to rate and temperature dependence that were used successfully in the yield stress discussion to explain in a qualitative way the observed fracture behaviour. 

The tensile tests on the composites with 50 vol% glass beads indicate that good adhesion was already obtained with a coating of five equivalent molecular layers of the silane, and the fracture behaviour of specimens fractured at - 196°C confirmed the earlier observations that an adhering layer of modified polyethylene is formed around the glass when treated with silane. 

Grellmann W, Seidler S (2001) Deformation and fracture behaviour of polymers. Springer, Berlin Heidelberg New York... 

Many studies have been performed on crazes and their relation to fracture behaviour most of them are reviewed in [ 17,18]. 

When considering fracture behaviour of polymers, an important feature, as mentioned, deals with craze fibril breakdown. Indeed, this latter mechanism leads to crack propagation and easier specimen fracture. 

Depending on the chemical structure of the polymer and on the experimental conditions (T and e), polymer solids can present a brittle behaviour, a ductile behaviour, or an intermediate fracture behaviour. 

For characterising the fracture behaviour of a bulk material, the interesting K c value is that corresponding to plane strain, K c. Thus, in order to measure K[c, it is necessary to get a large enough sample thickness, B. Actually, one has... 

Understanding the effect of the chemical structure of polymers on their fracture behaviour has been a challenging question, which has been studied for quite a long time. 

For these reasons, PMMA and its maleimide and glutarimide copolymers represent very suitable materials for investigating the effect of the chemical structure and of the solid state molecular motions on the plastic deformation, the occurrence of the various micro-mechanisms of deformation (chain scission crazes, shear deformation zones, chain disentanglement crazes), as well as the fracture behaviour. 

In order to understand fracture behaviour, it is important to analyse the types of deformation micromechanisms undergone under strain chain scission craze (CSC), shear deformation zone (SDZ), chain disentanglement craze (CDC) and the temperature range over which each one occurs. Furthermore, it is worth wondering whether these micromechanisms are related to /i transition motions. 

Many studies [40-43] have been performed on the fracture behaviour of PMMA as a function of temperature or cross-head speed. As an illustration, Fig. 30 shows the critical stress intensity factor, K c, in a log-log plot as a function of temperature for various crack speeds [40]. The temperature range is limited to + 80 °C in order to avoid ductile tearing. In the stable crack growth regime of interest here, whatever the crack speed, K c decreases with increasing temperature. 

So, it is quite clear that ft transition motions are involved in the fracture behaviour of PMMA. The continuous smooth decrease of K c with increasing... 

Depending on the temperature, MGIM36 and MGIM76 show two quite different fracture behaviours ... 

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