Crack Initiation at the Inclusions under Static Loading (original) (raw)
Related papers
2007
In this paper we are focused on influence of selected geometrical characteristics as are: inscribed circle diameter, circumscribed circle diameter, eccentricity, ovality and radius of curvature of inclusion on stress concentration around these defects modelling using by FEM. This task was solved as plane stress. From this point of view there are monitored and evaluated there factors: maximum value of stress along the loading, across the loading, shear stress and equivalent stresses. There will be also presented algorithms for automatic generation of models that make possible to practice statistical data processing.
The interaction between a crack and an inclusion
International Journal of Engineering Science, 1972
A numerical method described recently [ I] is used here to obtain the stress intensity factor for a crack near an inclusion. Results for the variation of the stress intensity factor with the distance of the crack tip from the inclusion, are shown graphically.
Effects of inclusions in ductile cracks
Zeitschrift für angewandte Mathematik und Physik, 2001
This paper examines the problems of the symmetric indentation of a ductile pennyshaped crack by an embedded rigid, thin, circular disc inclusion and a ductile Griffith crack by a line inclusion. The Dugdale hypothesis is adopted to determine the length of the plastic zone. Expressions for the resultant pressures applied to the inclusions are obtained. Numerical results for the length of plastic zones and resultant pressures are obtained and are displayed graphically. Keywords. Ductile penny-shaped crack, ductile Griffith crack, triple integral equation, Fredholm integral equation of the second kind, plastic zone, stress intensity factor, fracture mechanics, inclusions in elastic media.
Engineering Fracture Mechanics, 2014
Photoelasticity is employed to investigate the stress state near stiff rectangular and rhombohedral inclusions embedded in a 'soft' elastic plate. Results show that the singular stress field predicted by the linear elastic solution for the rigid inclusion model can be generated in reality, with great accuracy, within a material. In particular, experiments: (i.) agree with the fact that the singularity is lower for obtuse than for acute inclusion angles; (ii.) show that the singularity is stronger in Mode II than in Mode I (differently from a notch); (iii.) validate the model of rigid quadrilateral inclusion; (iv.) for thin inclusions, show the presence of boundary layers deeply influencing the stress field, so that the limit case of rigid line inclusion is obtained in strong dependence on the inclusion's shape. The introduced experimental methodology opens the possibility of enhancing the design of thin reinforcements and of analyzing complex situations involving interaction between inclusions and defects.
Composite Structures, 2019
A geometrically simplified plane elasticity problem of a finite small crack emanating from a thin interfacial zone surrounding the circular inclusion situated in the finite bounded domain is investigated. The inclusion can model a particle in a composite material. The crack is modelled using the distribution dislocation technique, which represents the so called inner solution or boundary layer of the studied problem. Its application is conditioned by the knowledge of the fundamental solution of the dislocation interacting with the inclusion and its interfacial zone. The fundamental solution is based on the application of Muskhelishvili complex potentials in the form of the Laurent series. The coefficients of the series are evaluated from the compatibility conditions along the interfaces of the inclusion, the interfacial zone and the matrix. Another supplement of the fundamental solution is its utilization for the so-called outer solution, which is the solution of the boundary integral method approximating the stress and strain relations along the external boundary of the domain containing the inclusion. The asymptotic analysis is introduced at the point of crack initiation to control the mismatch between the outer and the inner solutions along the external boundary of the studied domain. The asymptotic analysis results in the evaluation of the stress intensity factors as the leading terms of the asymptotic series expressed from the stress distribution near the crack tip, which lies in the matrix. The topological derivative is used to approximate the energy release rate field associated with the perturbing of the matrix by the finite small crack emanating from the interfacial zone. The assessed values of the energy release rate allow one to study the influence of the interfacial zone dimension and elastic properties on crack initiation under the conditions of finite fracture mechanics.
Interference Analysis between Crack and General Inclusion in an Infinite Plate by Body Force Method
Key Engineering Materials, 2013
A Continously Embedded Force Doublet over the Particular Region can be Regardedas the Distributing Eigen Strain. this Fact Implies that many Sorts of Inelastic Strain can Bereplaced by the Force Doublet. in the Present Paper, the Force Doublet is Used to Alter the Localconstitutive Relationship. as a Result, a Method for Analyzing the General Inclusion Problem Inwhich the Material Properties of the Inclusion are Not only Different from those of the Matrixmaterial but also can be even a Function of Spacial Coordinate Variables is Proposed. Thetheoretical Background of the Present Analysis is Explained Followed by some Representativenumerical Results.
EPJ Web of Conferences, 2010
Fracture toughness occurring in a material that has micro-cracks originating in its manufacture process may be improved by particle addition, these particles having different properties than the basic material [1]. This paper includes the outcome of a research on the influence of softer or harder particles added to the basic material, on the stresses occurring in the immediate vicinity of micro-cracks. Our research is designed to determine to what extent this process may result into preventing a crack from advancing into the material subject to unfavorable loads, depending on the direction of that crack. The outcome we achieved using finite element analysis supports the assumption that, by adding a certain amount of particles, which have specific characteristics, to the basic material, fracture toughness may increase significantly, [2].
Calculation of the Stress Intensity Factor in an Inclusion-Containing Matrix
Modeling and Numerical Simulation of Material Science
The intent of this paper is to propose an engineering approach to estimate the stress intensity factor of a micro crack emerging from an inclusion in relation with the morphology of the inclusion and its relative stiffness with the matrix. A micromechanical model, based on the FEA (finite element analysis) of the behavior of cracks initiated at micro structural features such as inclusions, has been developed using LEFM (Linear Elastic Fracture Mechanics) to predict the stress intensity factor of a micro crack emerging from an inclusion. Morphology of inclusions has important connotations in the development of the analysis. Stress intensity factor has been estimated from the FEA model for different crack geometries. Metallographic analysis of inclusions has been carried out to evaluate the typical inclusion geometry. It also suggests that micro cracks less than 1 µm behave differently than larger cracks.
Thin rigid inclusions with delaminations in elastic plates
European Journal of Mechanics - A/Solids, 2012
ABSTRACT In the paper, we propose an elastic plate model with delaminated thin rigid inclusions and provide mathematical analysis of the model. Both vertical and horizontal displacements of the plate are taken into account. It is assumed that the inclusion is delaminated which leads to an appearance of a crack. To provide a mutual non-penetration between crack faces we impose non-linear boundary conditions at the crack faces with unknown set of a contact. A correct problem formulation is proposed, and an existence of solutions is proved for different locations of the rigid inclusion inside of the elastic body.