Um método numérico para a modelagem de fraturamento coesivo em 3D

Neste trabalho apresenta-se um método que estende o modelo de fraturamento coesivo proposto por Hilleborg et al. 4,6. para problemas tri-dimensionais. O principal objetivo é o estudo do efeito das dimensoes absolutas de elementos de materiais ceramicos em seu comportamento estrutural. As hipótese básicas e limitaçoes de tal método sao apresentadas e discutidas. O novo modelo obtido é entao apresentado a través da formulaçao matricial do problema coesivo. Esta formulaçao fornece um sistema de equaçoes nao-lineares que pode ser resolvido com o algoritmo de Newton-Raphson. O modelo é capaz de representar a evoluçao das zonas de processos inelásticos e das de fissura verdadeira para diferentes geometrias estruturais . A implementaçao computacional do modelo é feita utilizando-se técnicas de programaçao orientada para objetos e computaçao gráfica. Finalmente, apresenta-se um exemplo em que uma soluçao tri-dimensional gerada com este modelo matemático é comparada com a soluçao di-dimensional conhecida na literatura

Análisis lineal y no lineal de propagación de fisuras en hormigón

Discrete crack propagation in concrete structures is now feasible by using an interactive-graphics computer system. This paper presents a theoretical model, suitable for two-dimensional crack propagation in concrete, as well as a description of the computer code. Analysis of two practical situations exemplifies the versatility and power of the developed system

Numerical Simulation Of 3d Hydraulic Fracture Using Newtonian And Power-law Fluids

Three-dimensional numerical simulations of hydraulic fracturing processes associated with arbitrarily oriented, perforated wellbores are presented. The objective is to enable the simulation of multiple, non-planar fractures in the near-wellbore region of perforated wellbores. A system that couples the structural response of a fractured rock with the flow of a Newtonian or power-law fluid between the fracture walls is described. Example applications are presented and compared to published solutions to validate the system. Capabilities to handle complex geometries are illustrated by examples of propagation of fractures oriented arbitrarily with respect to the in situ stresses. © 1993.30712651271Clark, A hydraulic process for increasing the productivity of wells (1949) Transactions of the AIME, 186, p. 1Howard, Fast, Hydraulic Fracturing (1970) Monograph Series, 2. , SPE, Richardson, TXHaimson, Fairhurst, Initiation and extension of hydraulic fractures in rocks (1967) Society of Petroleum Engineers Journal, 7, pp. 310-318Geertsma, Two-dimensional fracture propagation models (1989) Recent Advances in Hydraulic Fracturing, 12, pp. 81-94. , Monograph Series, SPE, Richardson, TXMendelsohn, A review of hydraulic fracture modeling - I: General concepts, 2D models, motivation for 3D modeling (1984) J. Energy Res. Tech., 106, pp. 369-376Mendelsohn, A review of hydraulic fracture modeling - II: 3D modeling and vertical growth in layered rock (1984) J. Energy Res. Tech., 106, pp. 543-553Settari, Cleary, Development and testing of a pseudo-three-dimensional model of hydraulic fracture geometry (1986) SPE, Trans. AIME, 281, pp. 449-466Boutéca, Hydraulic fracturing model based on a three-dimensional closed form Tests and analysis of fracture geometry and containment (1988) SPE Production Engineering, 3, pp. 445-454Advani, Lee, Lee, Three dimensional modeling of hydraulic fractures in layered media: Finite element formulations (1990) J. Energy Res. Tech., 112, pp. 1-18Vandamme, Jeffrey, Curran, Pressure distribution in three-dimensional hydraulic fractures (1988) SPE Production Engineering, 3, pp. 181-186Ben Naceur, Thiercelin, Touboul, Simulation of fluid flow in hydraulic fracturing Implications for 3D propagation (1990) SPE Production Engineering, pp. 133-143Clifton, Abou-Sayed, On the computation of the three-dimensional geometry of hydraulic fractures (1979) Paper SPE 7943Martha, Topological and Geometrical Modeling Approach to Numerical Discretization and Arbitrary Fracture Simulation in Three Dimensions (1989) PhD. Thesis, , Cornell University, Ithaca, N.YWawrzynek, Discrete Modeling of Crack Propagation: Theoretical Aspects and Implementation Issues in Two and Three Dimensions (1991) PhD. Thesis, , Cornell University, Ithaca, N.YLutz, Numerical Methods for Hypersingular and Near Singular Boundary Integrals in Fracture Mechanics (1991) PhD. Thesis, , Cornell University, Ithaca, N.YSousa, Three-Dimensional Simulation of Near-Wellbore Phenomena Related to Hydraulic Fracturing from a Perforated Wellbore (1992) PhD. Thesis, , Cornell University, Ithaca, N.YNolte, Economides, Pressure analysis during fracturing (1987) Reservoir Stimulation, pp. 7.1-7.17. , M.J. Economides, K.G. Nolte, Schlumberger Educational Services, Houston, TXConstien, Fracturing fluid and proppant characterization (1987) Reservoir Stimulation, pp. 5.1-5.23. , M.J. Economides, K.G. Nolte, Schlumberger Educational Services, Houston, TXBird, Stewart, Lightfoot, (1960) Transport Phenomena, , John Wiley and Sons Publishing Co, New York, N.YWawrzynek, Martha, Ingraffea, FRANSYS: a software system for the simulation of crack propagation in three dimensions (1990) IUTAM/IACM Symposium, pp. 273-282. , G. Kuhn, H. Mang, Discretization Methods in Structural Mechanics, Springer-Verlag, New YorkPotyondy, Gray, Ingraffea, Simulation of 3D non-planar fatigue crack growth in a turbine root blade (1992) Presented at ASME Pressure Vessels and Piping Summer Conference, , New Orleans, LouisianaSousa, Martha, Wawrzynek, Ingraffea, Simulation of non-planar crack propagation in structures of concrete and rock (1989) Fracture of Concrete and Rock - Recent Developments, pp. 254-264. , S.P. Shah, S.E. Swartz, B. Barr, Elsevier Applied SciencsCrouch, Starfield, (1983) Boundary Element Methods in Solid Mechanics, , George Allen - Unwin, LondonVandamme, A Three-Dimensional Displacement Discontinuity Model for the Analysis of Hydraulically Propagated Fractures (1986) PhD. Thesis, , University of Toronto, CanadaLyness, Owen, Zienkiewicz, Finite element analysis of the steady flow of non-Newtonian fluids through parallel sided conduits (1974) Finite Element Methods in Flow Problems, pp. 489-503. , J.T. OdenSettari, A new general model of fluid loss in hydraulic fracturing (1985) Society of Petroleum Engineers Journal, pp. 491-501. , AugustMorales, H., Personal Communication, 1991Behrmann, Elbel, Effect of perforations on fracture initiation (1991) Journal of Petroleum Technology, pp. 608-615Sousa, Lutz, Ingraffea, Three-dimensional simulation of hydraulically driven fracture propagation in a rock mass (1991) Symposium on Fracture Processes in Brittle Disordered Materials, , Noordwijk, The Netherland

An overview of integration methods for hypersingular boundary integrals

Several methods of analyzing the hypersignular gradient BIE have been developed recently. This paper is a review highlighting the numerous common aspects and several differences among the methods. Significant common aspects include (a) a regularization of constant and linear terms, (b) analysis of integration points near rather than on the surface, and (c) analysis of the neighborhood of the singular point rather than of individual elements. 26 refs