Fracture mechanics, elastomers

Mars, W.V., Comparison of fatigue crack growth characterizations made at several labs, presented at Fracture Mechanics for Elastomers 50 Not Out, Proceedings of Anniversary Meeting Tun Abdul Razak Research Centre, Hertford, United Kingdom, 2008. 

We can consider the spreading of a sessile drop on a soft, lossy substrate rather like the advance of a negative crack and thus use fracture mechanics concepts, as was the case in the derivation of Eq. (15) for the separation of an elastomer from a rigid solid. The term negative is used since the spreading of a drop leads to the creation of solid/liquid interface rather than separation. 

So far, we have considered the elasticity of filler networks in elastomers and its reinforcing action at small strain amplitudes, where no fracture of filler-filler bonds appears. With increasing strain, a successive breakdown of the filler network takes place and the elastic modulus decreases rapidly if a critical strain amplitude is exceeded (Fig. 42). For a theoretical description of this behavior, the ultimate properties and fracture mechanics of CCA-filler clusters in elastomers have to be evaluated. This will be a basic tool for a quantitative understanding of stress softening phenomena and the role of fillers in internal friction of reinforced rubbers. 

Schneider, K Schone, A. (2008). Online-structure characterisation of polymers during deformation and relaxation by Synchrotron-SAXS and WAXS, In Reinforced Elastomers Fracture Mechanics, Statistical Physics and Numerical Simulations Kaliske, M. Heinrich, G. Verron, E. (Eds.) EUROMECH Colloquium 502, Dresden, 2008 pp. 79-81... 

The deformation characteristic of more ductile polymer materials at ambient temperatures like most thermoplastics or all elastomers is highly non-linear, e.g., either mostly viscoelastic or entropy-elastic or a combination of both. Compared to concepts of LEFM relatively rarely used for polymer materials different concepts of non-linear elastic firacture mechanics such as elastic-plastic fracture mechanics (EPFM) or post-yield fracture mechanics (PYFM) are somewhat widely applied, therefore. One of the most important concepts of EPFM is the J integral concept. Notwithstanding the J integral is primarily defined to be valid... 

Rei Reincke, K., Kliippel, M., Grellmann, W. Investigation of fracture mechanical properties of filler-reinforced styrene—butadiene elastomers. Kautschuk Gummi Kunstst. 62 (2009) 246—251. 

Reincke, K., Grellmann, W., Each, R., Heinrich, G. Toughness optimization of SBR elastomers - Use of fracture mechanics methods for characterization. Macromol. Mater. Eng. 288 (2003) 181-189. 

Gre Grellmann, W., Reincke, K. Technical material diagnostics - Fracture mechanics of filled elastomer blends. In Grellmann, W., Heinrich, Kaliske, M., G., Kliippel, M., Schneider, K., Vilgis, T. (eds.) Fracture mechanics and statistical mechanics of reinforced elastomeric blends. Lecture Notes in Applied and Computational Mechanics, Vol. 70, Springer, Berlin, 2013, 227-268. 

Klti Kliippel, M. Evaluation of viscoelastic master curves of filled elastomers and applications to fracture mechanics. J. Phys. Condens. Matter 21 (2009) 035104 (10 pages). 

In a contribution from B. F. Goodrich, Drake and Siebert extensively review the journal and patent literature since 1975 on reactive butadiene/acrylonitrile liquid and solid elastomers used in formulating epoxy structural adhesives. Areas reviewed include the preparation of elastomer-modified epoxy resins, the characterization of rubber-toughened epoxy resins, fracture mechanics and adhesive formulation and testing. 

The criteria for cavitation in polymers modified with rubbers were modeled by Lazzeri and Bucknall (Bucknall et al. 1994 Lazzeri and Bucknall 1993, 1995). They are based on energy release rate principles similar to those used in fracture mechanics. Void nucleation and expansion in elastomer particles are accompanied by the formation of a new surface, significant stretching of the surrounding layers of elastomer, and the stress relaxatimi in the adjacent matrix. All of these are driven by... 

In Section 6.8, CNIS data are compared with measurements of strain energy release rates G/ obtained under the well-defined criteria of linear elastic fracture mechanics of materials under the conditions of small-scale yielding. A variety of polypropylene resins, their blends with elastomers, rigid fillers, or both are included in this study. 

In special cases, such as elastomers or other high-elongation materials, bulk plastic or nonlinear behavior of the material does occur. For these cases there have been theories proposed. Chapter 1 discussed the generalized fracture mechanics theory developed by Andrews in which the effect of variables such as crack speed, temperature, and magnitude of strain on the strain energy release rate is considered. ... 

Figure 11.22 Important specimen shapes tor the determination of the characteristic energy and stress intensity parameters for fracture mechanics (40) (a) Trouser-leg design, often used with elastomers, (b) Center-notched panel, (c) Edge-notched panel, (d) Cantilever-beam type. Types (b)-(d) are used for plastics.

Keywords linear elastic fracture mechanics, critical strain energy release rate, precipitating elastomers, hyperbranched molecules, preformed rubber particles, core-shell latex particles, treated rubber, precipitating thermoplastic particles, preformed thermoplastic particles, crack bridging, shear banding, cavitation. 

A study was made of gas decompression failures in elastomeric seals using a fracture mechanics approach with considerations of gas permeation. An equation is proposed for the tearing energy associated with crack growth from internal gas bubbles in a finite thickness elastic media. The effects of gas pressure, temperature, rate of decompression and mechanical strain were studied for a range of elastomers used in oil and gas sealing applications. A theoretical treatment is presented based on a fracture mechanics criterion for fracture from an internal disc shaped flaw in a thick elastic medium. Permeation theory provides a quantification of the amount of gas available internally to initiate failures. 21 refs. 

Dallas, Tx., 19-22nd April 1988, Paper 1, pp.36. 012 FRACTURE MECHANISMS AND LIFE PREDICTIONS FOR ELASTOMERS IN HIGH PRESSURE OIL AND GAS ENVIRONMENTS Stevenson A Campion R P MATERIALS ENGINEERING RESEARCH LABORATORY LTD. 

Before we proceed, a word of caution is necessary here in terms of our use of the parameter In fracture mechanics, has the meaning of an energy per unit area necessary for a crack to advance. For elastic elastomers, is a unique function of the velocity of the advancing crack and can be determined with a fracture mechanics test such as the JKR test [24]. 

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