Double fracture model

A new model for material removal mechanism was proposed based on the experimental evidences. The "Double Fracture Model" was proved in the stock removal mechanism of ceramics lapping. 

Marinescu, I.D., Double fracture model in lapping of ceramics. Proceedings ofASPE, Spring Meeting, June 2-4, Annapolis, MD. 

Chapter 11 is one of the chapters with emphasis on fundamentals and presents an original model for lapping of ceramics the double fracture model. I developed this model with my students over the past fifteen years, trying to provide a more complex material removal model in the case of lapping of ceramics (indentation and scratch). 

The oil industry has developed and used a double porosity model to describe flow in certain fracture systems (7). Little data on application to actual field problems are available in the literature suggesting that this model has had only limited success and has been used only after the fact, not in a predictive mode. 

With the possible exception of selenium, a two-site, double first-order (DFO) model shows an improvement over single site-models for describing sorption of the radionuclides studied. The dependence of sorption on alteration history in the majority of cases indicates that experiments with systems representative of well-weathered fracture systems are necessary to obtain data applicable to actual disposal vault conditions. 

Fractionation of chain molecules according to their chain length, 727 Fracture mechanics, 472 Free enthalpy of formation, 753, 754 Freely jointed chain model, 247 Free-rotation model, 246 Free surface energy, 229 Free volume fraction, 537 Freeze-off time, 806 Freezing-in process, 151 Frequency doubling, 349 factor, 751... 

Aquifers with double porosity (e.g. sandstones with fractures and pore volume) require special considerations with regard to transport modeling even if no reactive mass transport in its proper sense is taken into account. This problem is demonstrated with the following example of an aquifer regeneration in an uranium mine. The ore was leached in this mine by in-situ leaching (ISL) using sulfuric acid. The hydrochemical composition of the water that is in the aquifer after this in-situ leaching process is shown as ISL in Table 40 ... 

Brown HR (2007) A model ofthe fracture of double network gels. Macromolecules 40 3815-3818... 

Wu Y and Zhang Z. 1996. An application of generalized double porosity media model for coupled stress and groundwater flow analysis in fractured rock mass. J. of Engineering Geology, 1(3), pp. 40-46. 

The results for the particle travel times for various constant hydraulic apertures and fracture densities from the repository to the seabed are presented graphically in Figure 4. For the low fracture density case, the hydraulic conductivity estimated for a block size of 25 m x 25 m has been used even though this size does not correspond to the REV, which is estimated to be greater than 100 m x 100 m. This block size does allow, however, a calculation of the mechanical closure of the fracture apertures for the HM case and therefore a comparison of the results between the two cases for low-density conditions. The results of the continuum model based on constant hydraulic apertures display very rapid mean particle travel times from the repository to the seabed. For example, for the low and high fracture density networks adopting a constant hydraulic aperture of 10 pm, particle travel times from the repository to the seabed are 580 years and 106 years respectively. A doubling of the aperture increases the conductivity by a factor of... 

Bai, M. and Roegiers, J.C. 1994. Fluid flow and heat flow in deformable fractured porous media. Int. J. Engng Sci. 32(10) pp. 1615-1633. Callari C. Federico F. 2000. FEM validation of a double porosity elastic model for consolidation of structurally complex clayey soils. Int. J. Numer. Analy. Meth. 24 (4) pp. 367-402. 

Coal is a kind of uneven double porous media made up of macro-cracks and micro-pores. Gas in coal seam remains in the macro-cracks and micropores in free state and adsorbed state. Once getting pressure relief, gas in coal seam begins to flow along the pores and fractures, while the absorbed gas is desorbed. Gas flow in Coal seam is actually a very complex process affected by many factors. In order to simplify the process, the coal seam gas flow model has the following assumptions—(Wang Xiaoliang, et. al, 2003). 

Kanninen, M.F. (1973) An augmented double cantilever beam model for studying crack propagated and arrest. International Journal of Fracture, 9, 83-92. 

M.F. Kanninen, "An Augmented Double Cantilever Beam Model for Studying Crack Propagation and Arrest," Int. J. Fracture, 83 (1973). 

The XPS studies of the fractured samples were done using a Physical Electronics ESCA/SAM Model 550 electron spectrometer. Data acquisition was accomplished using a SAM 550 data system and a Digital PDP-1104 computer. The punched samples were mounted with double sided stick tape. The binding energies were referenced to the C Is photopeak at 284.6 eV. Wide scan (0 to 1100 eV) spectra were used to identify the major elements present on the surface of the samples. Samples were scanned repetitively to obtain the atomic fractions of elements present in the sample surface. 

There are numerous examples of the application of fracture mechanics to structural adhesive systems. Most notable are those of Mostovoy and his coworkers which have already been mentioned. " Bascom and coworkers have made significant contributions to the understanding of the effect of bondline thickness on fracture toughness. Kinloch and Shaw extend the work of Bascom to include rate effects and to develop mathematical models of the fracture resistance of adhesives. Hunston et al have used these methods to study viscoelastic behavior in the fracture process of structural adhesives.Mostovoy and Ripling used these techniques to determine the flaw tolerance of several adhesives,while Bascom and Cottington have studied the effect of flaws caused by air entrapment in structural adhesives." Finally it must be mentioned that one of the most simple, most widely used tests for strucural adhesives, the peel test, is actually a version of the double cantilever beam test. 

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