Brittle Fracture And Damage Of Brittle Materials And Composites

Flaws are the principal source of fracture in many materials, whether brittle or ductile, whether nearly homogeneous or composite. They are introduced during either fabrication or surface preparation or during exposure to aggressive environments (e. g. oxidation, shocks). The critical flaws act as stress concentrators and initiate cracks that propagate instantaneously to failure in the absence of crack arrest phenomena as encountered in brittle materials. This book explores those brittle materials susceptible to crack arrest and the flaws which initiate crack induced damage. A detailed description of microstructural features covering numerous brittle materials, including ceramics, glass, concrete, metals, polymers and ceramic fibers to help you develop your knowledge of material fracture. Brittle Failure and Damage of Brittle Materials and Composites outlines the technological progress in this field and the need for reliable systems with high performances to help you advance the development of new structural materials, creating advantages of low density, high resistance to elevated temperatures and aggressive environments, and good mechanical properties. The effects of flaw populations on fracture strength The main statistical-probabilistic approaches to brittle fracture The use of these methods for predictions of failure and effects induced by flaw populations The application of these methods to component design The methods of estimation of statistical parameters that define flaw strength distributions The extension of these approaches to damage and failure of continuous fiber reinforced ceramic matrix composites

Supports the use and development of strong, fracture-resistant, and mechanically reliable ceramic materials The Fracture of Brittle Materials thoroughly sets forth the key scientific and engineering concepts underlying the selection of test procedures for fracture toughness, strength determination, and reliability predictions. With this book as their guide, readers can confidently test and analyze a broad range of brittle materials in order to make the best use of existing materials as well as to support the development of new materials. The authors explain the importance of microstructure in these determinations and describe the use of quantitative fractography in failure analysis. The Fracture of Brittle Materials is relevant to a broad range of ceramic materials (i.e., any inorganic non-metal), including semiconductors, cements and concrete, oxides, carbides, and nitrides. The book covers such topics as: Basic principles of fracture mechanics underlying brittle material tests and analysis procedures Theory and mechanisms of environmentally enhanced crack growth Fracture mechanics tests to determine a material's resistance to fast fracture Test and analysis methods to assess the strength of ceramics Methods to analyze the fracture process based on quantitative measurements of the fracture surface Effect of a material's microstructure Methods for predicting the lifetime of brittle components under stress Throughout the book, figures and illustrations help readers understand key concepts and methods. Replete with real-world examples, this text enables engineers and materials and ceramics scientists to select and implement the optimal testing methods for their particular research needs and then accurately analyze the results.

The paper is focused on an estimation of the extent of the fracture process zone and the zone of cumulative damage evolving during tensile failure of structures made of quasi-brittle materials, e.g. cementitious composites. The zone is determined via a developed (semi-)analytical method based on a combination of multi-parameter linear elastic fracture mechanics, cohesive crack models and plasticity theory. Results of the method are verified by numerical simulations of three-point bending of notched beams using an academic computational code based on a discrete spring network (lattice-particle) model and programs based on continuum modelling (finite elements), both with implementation of the cohesive zone approach. Three materials differing in cohesive behaviour are considered in the study; apart from the classical quasi-brittle softening material also a quasi-ductile and a strain hardening ones are taken into account. Used simulation tools provide sound results, particularly in the case of the softening material. Moreover, significant potential of the developed modelling techniques is presented.

From a November 2000 symposium in Orlando, Florida, 14 papers review the new standards promulgated by American, European, and Japanese professional associations for testing fracture toughness, slow crack growth, and biaxial strength in brittle ceramics. They address a variety of topics regarding imp

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.

This text comprises different basic aspects of brittle failure for rocks. It considers classical and contemporary models, as well as failure patterns under different loading schemes.