Journal ArticleDOI
Determination of fracture energy, process zone longth and brittleness number from size effect, with application to rock and conerete
Zdenek P. Bazant,Mohammad Kazemi +1 more
TLDR
In this paper, the dependence of the fracture energy and the effective process zone length on the specimen size as well as the craek extension from the notch is analyzed on the basis of Ba<zant's approximate size effect law.Abstract:
The dependence of the fracture energy and the effective process zone length on the specimen size as well as the craek extension from the notch is analyzed on the basis of Ba<zant's approximate size effect law. The fracture energy and the effective length of the fracture process zone is defined on the basis of the extrapolation to an infinite specimen size, for which the definitions are independent of the shape of the specimen or structure. Both of these material properties are expressed in terms of the size effect law parameters and the function describing the nondimensional energy release rate. Ba<zant's size effect law for the nominal stress σN at failure is reformulated in a manner in which the parameters are the fracture energy and the effective (elastically equivalent) process zone length. A method to determine these material properties from σN-data by linear and nonlinear regressions is shown. This method permits these properties to be evaluated solely on the basis of the measured maximum loads of specimens of various sizes and possibly also of different shapes. Variation of both the fracture energy and the effective process zone length as a function of the specimen size is determined. The theoretical results agree with previous fracture tests of rock as well as concrete and describe them adequately in relation to the inevitable random scatter of the tests.read more
Citations
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Journal ArticleDOI
Cohesive Zone Models: A Critical Review of Traction-Separation Relationships Across Fracture Surfaces
TL;DR: In this article, potential-based models have been evaluated for mixed-mode cohesive fracture, and it is shown that these models lead to positive stiffness under certain separation paths, contrary to general cohesive fracture phenomena wherein the increase of separation generally results in the decrease of failure resistance across the fracture surface.
Journal ArticleDOI
Random particle model for fracture of aggregate or fiber composites
TL;DR: In this article, a particle model for brittle aggregate composite materials such as concretes, rocks, or ceramics is presented, which is also applicable to the behavior of unidirectionally reinforced fiber composites in the transverse plane.
Journal ArticleDOI
Concrete fracture models: testing and practice
TL;DR: In this article, the authors reviewed the existing fracture models for concrete and the testing methods for fracture energy and other fracture characteristics and some new results on the relationship between fracture testing and size effect are presented.
Journal ArticleDOI
Fracture toughness of geopolymeric concretes reinforced with basalt fibers
TL;DR: In this article, the authors investigated the influence of the volumetric fraction of the fibers on the fracture toughness of geopolymeric cement concretes reinforced with basalt fibers, and found that the concretized concrete has better fracture properties than conventional Portland cement.
Journal ArticleDOI
Determination of double-K criterion for crack propagation in quasi-brittle fracture, Part II: Analytical evaluating and practical measuring methods for three-point bending notched beams
Shilang Xu,Hans W. Reinhardt +1 more
TL;DR: In this paper, an attempt is made to determine the double-K fracture parameters using three-point bending notched beams using a linear asymptotic superposition assumption, based on the knowledge from extensive investigations which showed that the nonlinearity of P-CMOD curve is mainly associated with crack propagation.
References
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Book
The stress analysis of cracks handbook
TL;DR: The Stress Analysis of Cracks Handbook as mentioned in this paper provides a comprehensive, easy-to-access collection of elastic stress solutions for crack configurations, along with other relevant information, such as displacements, crack opening areas, basic stress functions source references, accuracy of solutions, and more.
Journal ArticleDOI
Size Effect in Blunt Fracture: Concrete, Rock, Metal
TL;DR: In this article, the authors studied the structural size effect of fracture in concrete and rock structures, using dimensional analysis and illustrative examples, and showed that the energy release caused by fracture depends on both the length and the area of the crack band.
Journal ArticleDOI
The theoretical basis of a method to determine the fracture energy GF of concrete
TL;DR: In this article, the significance of fracture energy in the strength of concrete structures is discussed and it is demonstrated that GF in some cases, for example for shear failure of beams and slabs without shear reinforcement, is a material property which may be as important as normal strength properties.