Author: Guanshui Xu
Publisher:
ISBN:
Category :
Languages : en
Pages : 224
Book Description
Three Dimensional Elastic Analysis of Crack Growth and Toughening Mechanisms of Brittle Matrix Composites
Toughening Mechanisms in Quasi-Brittle Materials
Author: S.P. Shah
Publisher: Springer Science & Business Media
ISBN: 9401133883
Category : Science
Languages : en
Pages : 590
Book Description
A variety of ceramic materials has been recently shown to exhibit nonlinear stress strain behavior. These materials include transformation-toughened zirconia which undergoes a stress-induced crystallographic transformation in the vicinity of a propagating crack, microcracking ceramics, and ceramic-fiber reinforced ceramic matrices. Since many of these materials are under consideration for structural applications, understanding fracture in these quasi-brittle materials is essential. Portland cement concrete is a relatively brittle material. As a result mechanical behavior of concrete, conventionally reinforced concrete, prestressed concrete and fiber reinforced concrete is critically influenced by crack propagation. Crack propagation in concrete is characterized by a fracture process zone, microcracking, and aggregate bridging. Such phenomena give concrete toughening mechanisms, and as a result, the macroscopic response of concrete can be characterized as that of a quasi-brittle material. To design super high performance cement composites, it is essential to understand the complex fracture processes in concrete. A wide range of concern in design involves fracture in rock masses and rock structures. For example, prediction of the extension or initiation of fracture is important in: 1) the design of caverns (such as underground nuclear waste isolation) subjected to earthquake shaking or explosions, 2) the production of geothermal and petroleum energy, and 3) predicting and monitoring earthquakes. Depending upon the grain size and mineralogical composition, rock may also exhibit characteristics of quasi-brittle materials.
Publisher: Springer Science & Business Media
ISBN: 9401133883
Category : Science
Languages : en
Pages : 590
Book Description
A variety of ceramic materials has been recently shown to exhibit nonlinear stress strain behavior. These materials include transformation-toughened zirconia which undergoes a stress-induced crystallographic transformation in the vicinity of a propagating crack, microcracking ceramics, and ceramic-fiber reinforced ceramic matrices. Since many of these materials are under consideration for structural applications, understanding fracture in these quasi-brittle materials is essential. Portland cement concrete is a relatively brittle material. As a result mechanical behavior of concrete, conventionally reinforced concrete, prestressed concrete and fiber reinforced concrete is critically influenced by crack propagation. Crack propagation in concrete is characterized by a fracture process zone, microcracking, and aggregate bridging. Such phenomena give concrete toughening mechanisms, and as a result, the macroscopic response of concrete can be characterized as that of a quasi-brittle material. To design super high performance cement composites, it is essential to understand the complex fracture processes in concrete. A wide range of concern in design involves fracture in rock masses and rock structures. For example, prediction of the extension or initiation of fracture is important in: 1) the design of caverns (such as underground nuclear waste isolation) subjected to earthquake shaking or explosions, 2) the production of geothermal and petroleum energy, and 3) predicting and monitoring earthquakes. Depending upon the grain size and mineralogical composition, rock may also exhibit characteristics of quasi-brittle materials.
3-D Analysis and Verification of Fracture Growth Mechanisms in Fiber- Reinforced Ceramic Composites
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 28
Book Description
This final report documents a 3-D computational and experimental investigation into the mechanics of roughening a brittle matrix by incorporating long brittle fibers. Computationally, small scale failure mechanisms ahead of a crack are explicitly modeled and merged with a continuum representation of the far field outside the process zone. Particular attention is given to the interfacial decohesion and frictional slipping near the tip of a matrix crack which is impinging upon an inclusion. The surface integral and finite element (SIFEH) method, which employs the principle of superposition to combine the best features of two powerful numerical techniques, provides an extremely flexible and efficient computational platform for modeling linear elastic fractures near material inhomogeneities. Applications to general 3-D fracture growth in multimaterial media demonstrate the capabilities of the computational technique and are also described. The computational simulation is being guided by laboratory experiments. Crack growth observations made on a model (micro- ) structure comprising a glass rod embedded in a cement matrix show the toughening mechanisms of crack pinning and crack bridging in operation. In a second experiment, interfacial slip evolution was modeled experimentally for planar bimaterial interfaces. This combined experimental and numerical program has provided insight into optimal combinations of the key parameters (e.g. residual stresses at interface, friction coefficient, strength of fibers) to maximize toughness ... Fracture mechanics, Fiber-reinforced composites, Ceramic composite materials, Surface-integral methods.
Publisher:
ISBN:
Category :
Languages : en
Pages : 28
Book Description
This final report documents a 3-D computational and experimental investigation into the mechanics of roughening a brittle matrix by incorporating long brittle fibers. Computationally, small scale failure mechanisms ahead of a crack are explicitly modeled and merged with a continuum representation of the far field outside the process zone. Particular attention is given to the interfacial decohesion and frictional slipping near the tip of a matrix crack which is impinging upon an inclusion. The surface integral and finite element (SIFEH) method, which employs the principle of superposition to combine the best features of two powerful numerical techniques, provides an extremely flexible and efficient computational platform for modeling linear elastic fractures near material inhomogeneities. Applications to general 3-D fracture growth in multimaterial media demonstrate the capabilities of the computational technique and are also described. The computational simulation is being guided by laboratory experiments. Crack growth observations made on a model (micro- ) structure comprising a glass rod embedded in a cement matrix show the toughening mechanisms of crack pinning and crack bridging in operation. In a second experiment, interfacial slip evolution was modeled experimentally for planar bimaterial interfaces. This combined experimental and numerical program has provided insight into optimal combinations of the key parameters (e.g. residual stresses at interface, friction coefficient, strength of fibers) to maximize toughness ... Fracture mechanics, Fiber-reinforced composites, Ceramic composite materials, Surface-integral methods.
Three-Dimensional Gear Crack Propagation Studies
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 18
Book Description
Three-dimensional crack growth simulation was performed on a split-tooth gear design using boundary element modeling and linear elastic fracture mechanics. Initial cracks in the fillet of the teeth produced stress intensity factors of greater magnitude (and thus, greater crack growth rates) than those in the root or groove areas of the teeth. Crack growth simulation was performed on a case study to evaluate crack propagation paths. Tooth fracture was predicted from the crack growth simulation for an initial crack in the tooth fillet region. Tooth loads on the uncracked mesh of the split-tooth design were up to five times greater than those on the cracked mesh if equal deflections of the cracked and uncracked teeth were considered. Predicted crack shapes as well as crack propagation life are presented based on calculated stress intensity factors, mixed-mode crack propagation trajectory theories, and fatigue crack growth theories.
Publisher:
ISBN:
Category :
Languages : en
Pages : 18
Book Description
Three-dimensional crack growth simulation was performed on a split-tooth gear design using boundary element modeling and linear elastic fracture mechanics. Initial cracks in the fillet of the teeth produced stress intensity factors of greater magnitude (and thus, greater crack growth rates) than those in the root or groove areas of the teeth. Crack growth simulation was performed on a case study to evaluate crack propagation paths. Tooth fracture was predicted from the crack growth simulation for an initial crack in the tooth fillet region. Tooth loads on the uncracked mesh of the split-tooth design were up to five times greater than those on the cracked mesh if equal deflections of the cracked and uncracked teeth were considered. Predicted crack shapes as well as crack propagation life are presented based on calculated stress intensity factors, mixed-mode crack propagation trajectory theories, and fatigue crack growth theories.
Three-dimensional Analysis of Crack Growth
Author: Yaoming Mi
Publisher: Computational Mechanics
ISBN:
Category : Nature
Languages : en
Pages : 208
Book Description
Publisher: Computational Mechanics
ISBN:
Category : Nature
Languages : en
Pages : 208
Book Description
Fracture Mechanics of Ceramics
Author: R.C. Bradt
Publisher: Springer Science & Business Media
ISBN: 1461533503
Category : Technology & Engineering
Languages : en
Pages : 592
Book Description
These volumes, 9 and 10, of Fracture Mechanics of Ceramics constitute the proceedings of an international symposium on the fracture mechanics of ceramic materials held at the Japan Fine Ceramics Center, Nagoya, Japan on July 15, 16, 17, 1991. These proceedings constitute the fifth pair of volumes of a continuing series of conferences. Volumes 1 and 2 were from the 1973 symposium, volumes 3 and 4 from a 1977 symposium, and volumes 5 and 6 from a 1981 symposium all of which were held at The Pennsylvania State University. Volumes 7 and 8 are from the 1985 symposium which was held at the Virginia Polytechnic Institute and State University. The theme ofthis conference, as for the previous four, focused on the mechanical behavior ofceramic materials in terms of the characteristics of cracks, particularly the roles which they assume in the fracture processes and mechanisms. The 82 contributed papers by over 150 authors and co-authors represent the current state of that field. They address many of the theoretical and practical problems ofinterest to those scientists and engineers concerned with brittle fracture.
Publisher: Springer Science & Business Media
ISBN: 1461533503
Category : Technology & Engineering
Languages : en
Pages : 592
Book Description
These volumes, 9 and 10, of Fracture Mechanics of Ceramics constitute the proceedings of an international symposium on the fracture mechanics of ceramic materials held at the Japan Fine Ceramics Center, Nagoya, Japan on July 15, 16, 17, 1991. These proceedings constitute the fifth pair of volumes of a continuing series of conferences. Volumes 1 and 2 were from the 1973 symposium, volumes 3 and 4 from a 1977 symposium, and volumes 5 and 6 from a 1981 symposium all of which were held at The Pennsylvania State University. Volumes 7 and 8 are from the 1985 symposium which was held at the Virginia Polytechnic Institute and State University. The theme ofthis conference, as for the previous four, focused on the mechanical behavior ofceramic materials in terms of the characteristics of cracks, particularly the roles which they assume in the fracture processes and mechanisms. The 82 contributed papers by over 150 authors and co-authors represent the current state of that field. They address many of the theoretical and practical problems ofinterest to those scientists and engineers concerned with brittle fracture.
Fracture and Damage of Composites
Author: M. H. Aliabadi
Publisher: WIT Press
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 312
Book Description
Covering various aspects of dynamic fractures this book contains state-of-the-art contributions from leading scientists in the field of crack dynamics.
Publisher: WIT Press
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 312
Book Description
Covering various aspects of dynamic fractures this book contains state-of-the-art contributions from leading scientists in the field of crack dynamics.
Three-Dimensional Elastic Surface Cracks
Author: TA. Cruse
Publisher:
ISBN:
Category : Analytical methods
Languages : en
Pages : 24
Book Description
This paper discusses a variety of issues associated with the elastic fracture mechanics modeling of surface cracks; both analytical and experimental issues are addressed. The primary analytical focus is on the use of the boundary integral equation method for elastic fracture mechanics analysis. An advanced code is highlighted. A new formulation for three-dimensional crack-surface integral equations is presented with some new analytical results associated with the free-surface singularity. Essential agreements with the results of Benthem are obtained. Fatigue crack growth results for surface cracks in tension and bending are compared with analytical solutions. It is shown that surface cracks in tension grow essentially in accord with an elastic fracture mechanics prediction, whereas surface cracks in bending do not conform to the elastic prediction, based on surface values of the elastic stress-intensity factor. Some thoughts for further research are given.
Publisher:
ISBN:
Category : Analytical methods
Languages : en
Pages : 24
Book Description
This paper discusses a variety of issues associated with the elastic fracture mechanics modeling of surface cracks; both analytical and experimental issues are addressed. The primary analytical focus is on the use of the boundary integral equation method for elastic fracture mechanics analysis. An advanced code is highlighted. A new formulation for three-dimensional crack-surface integral equations is presented with some new analytical results associated with the free-surface singularity. Essential agreements with the results of Benthem are obtained. Fatigue crack growth results for surface cracks in tension and bending are compared with analytical solutions. It is shown that surface cracks in tension grow essentially in accord with an elastic fracture mechanics prediction, whereas surface cracks in bending do not conform to the elastic prediction, based on surface values of the elastic stress-intensity factor. Some thoughts for further research are given.
Scientific and Technical Aerospace Reports
15th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2, Volume 12, Issue 7/8
Author: John B. Wachtman
Publisher: John Wiley & Sons
ISBN: 0470315881
Category : Technology & Engineering
Languages : en
Pages : 682
Book Description
This volume is part of the Ceramic Engineering and Science Proceeding (CESP) series. This series contains a collection of papers dealing with issues in both traditional ceramics (i.e., glass, whitewares, refractories, and porcelain enamel) and advanced ceramics. Topics covered in the area of advanced ceramic include bioceramics, nanomaterials, composites, solid oxide fuel cells, mechanical properties and structural design, advanced ceramic coatings, ceramic armor, porous ceramics, and more.
Publisher: John Wiley & Sons
ISBN: 0470315881
Category : Technology & Engineering
Languages : en
Pages : 682
Book Description
This volume is part of the Ceramic Engineering and Science Proceeding (CESP) series. This series contains a collection of papers dealing with issues in both traditional ceramics (i.e., glass, whitewares, refractories, and porcelain enamel) and advanced ceramics. Topics covered in the area of advanced ceramic include bioceramics, nanomaterials, composites, solid oxide fuel cells, mechanical properties and structural design, advanced ceramic coatings, ceramic armor, porous ceramics, and more.