scholarly journals Interface Crack Approaching a Three-Material Joint

2020 ◽  
Vol 10 (1) ◽  
pp. 416 ◽  
Author(s):  
Jelena M. Djoković ◽  
Ružica R. Nikolić ◽  
Robert Ulewicz ◽  
Branislav Hadzima
Keyword(s):  
Plastic Zone ◽  
Energy Release ◽  
Interface Crack ◽  
Crack Deflection ◽  
The Other ◽  
Elastic Behavior ◽  
Release Rates ◽  
Linear Elastic ◽  
Energy Release Rates ◽  
Elastic Fracture

The problem of an interface crack that approaches a three-material joint with two interfaces is analyzed in this paper. Two possible cases are considered: the crack that lies at the interface between materials A and B, approaching the joint of materials A, B, and C, deflects into the interface between materials A and C or into the interface between materials B and C. Analysis is performed within restrictions imposed by the linear elastic fracture mechanics (LEFM), linear elastic behavior of materials, and the small plastic zone around the crack tip, based on the crack deflection criterion proposed by He and Hutchinson. That criterion is applied in this paper to a joint of the three homogeneous isotropic materials. The energy release rates for the crack deflection into one interface or the other are compared to each other, and, based on this comparison, a conclusion is drawn as to which of the two interfaces the crack would deflect. If the value of the ratio of the energy release rates GBC/GAC is greater than the ratio of the corresponding fracture toughnesses of the two interfaces, the crack will deflect into the BC interface. If this ratio is smaller than the ratio of the corresponding fracture toughnesses, the crack will deflect into the AC interface. Knowing the ratio of energy release rates for deflection into one interface or the other can be used for designing the interface, namely for prediction of the direction of further crack propagation.

Criteria for Prediction the Interfacial Crack Growth in Concrete

2016 ◽  
Vol 258 ◽  
pp. 514-517
Author(s):  
Jelena M. Djoković ◽  
Ružica R. Nikolić ◽  
Ján Bujňák ◽  
Branislav Hadzima
Keyword(s):  
Fracture Mechanics ◽  
Mechanical Behavior ◽  
Energy Release ◽  
Crack Growth ◽  
Interfacial Crack ◽  
Release Rates ◽  
Linear Elastic ◽  
Deformation And Fracture ◽  
Energy Release Rates ◽  
Elastic Fracture

To understand the mechanical behavior of the concrete structures, one must analyze deformation and fracture of the interfaces between the constituents of the material that the structure is made of. Criteria for predicting the crack growth along an interface, based on the linear elastic fracture mechanics concept, applied for the cement substrate/aggregate interface, are presented in this paper. The two possible directions of the interfacial crack growth – the crack propagation along the interface and the crack kinking away from the interface are considered, with the corresponding energy release rates. For the case of the crack approaching the interface from one of the materials – cement, the competition between the crack deflecting into the interface and the crack penetrating the interface is considered with the corresponding energy release rates.

Energy Release Rates and Related Balance Laws in Linear Elastic Defect Mechanics

1987 ◽  
Vol 54 (2) ◽  
pp. 388-392 ◽  
Author(s):  
J. W. Eischen ◽  
G. Herrmann
Keyword(s):  
Conservation Laws ◽  
Energy Release ◽  
Thermal Effects ◽  
Balance Laws ◽  
Release Rates ◽  
Direct Derivation ◽  
Linear Elastic ◽  
Linear Dynamic ◽  
Dynamic Elasticity ◽  
Energy Release Rates

A simple and direct derivation of certain balance (or conservation) laws for linear dynamic elasticity is presented including nonhomogeneities, thermal effects, anisotropy, and body forces. Additionally, the connection between the balance laws and energy release rates for defect motions is established.

Energy-based approach to fracture

2020 ◽  
pp. 506-528
Author(s):  
Lallit Anand ◽  
Sanjay Govindjee
Keyword(s):  
Fracture Mechanics ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Momentum Tensor ◽  
Linear Elastic Fracture Mechanics ◽  
J Integral ◽  
Linear Elastic ◽  
Energy Release Rates ◽  
Elastic Fracture

This chapter introduces the concept of energy release rates for linear elastic fracture mechanics. The concept of an energy release rate is defined and related to the criteria of Griffith with application in the context of bodies with point loads. Eshelby’s energy momentum tensor is also introduced and Rice’s path independent J-integral is derived, related to energy release rate, and applied to fracture problems.

A Standard Approach for Measuring Adhesion Energies in Stiction-Failed Microdevices

2006 ◽  
Author(s):  
Zayd C. Leseman ◽  
Steven Carlson ◽  
Xiaojie Xue ◽  
Thomas J. Mackin
Keyword(s):  
Strain Energy ◽  
Peel Test ◽  
Strain Energy Release ◽  
Piezo Actuator ◽  
Release Rates ◽  
Linear Elastic ◽  
Macro Scale ◽  
Energy Release Rates ◽  
Elastic Fracture ◽  
Strain Energy Release Rates

We present results from a new procedure developed to quantify the pull-off force and strain energy release rates associated with stiction-failure in microdevices. The method is analogous to a standard, macro-scale peel test, but carried out using micro-scale devices. Adhesion is initiated by lowering an array of microcantilevers that protrude from a substrate into contact with a separate substrate. Displacement is controlled by a piezo-actuator with sub-nm resolution while alignment is controlled using linear and tilt stages. An interferometric microscope is used to align the array and the substrate and to record deflection profiles and adhesion lengths during peel-off. This geometry is accurately modeled using linear elastic fracture mechanics, creating a robust, reliable, standard method for measuring adhesion energies in stiction-failed microdevices.

On Energy Release Rates and Configurational Forces for Interfacial Propagating Cracks: A Lattice Approach With a Brittle Erosion Technique

2016 ◽  
Vol 84 (2) ◽  
Author(s):  
Amir Mohammadipour ◽  
Kaspar Willam
Keyword(s):  
Energy Release ◽  
Interface Crack ◽  
Driving Forces ◽  
Configurational Forces ◽  
Bimaterial Interface ◽  
Release Rates ◽  
Material Forces ◽  
Energy Release Rates ◽  
Crack Tips ◽  
Lattice Approach

A numerical 2D lattice approach with an erosion algorithm is employed to analyze bimaterial interface fracture quantities in brittle heterogeneous materials in the context of linear elastic fracture mechanics (LEFM). The concept of configurational force is elucidated and the importance of nodal configurational changes in a mesh where no stress–strain analyses are needed is investigated. Three fracture problems, i.e., an infinite panel with a bi-material interface crack, a double-lap shear test, and a prenotched four-point bending masonry beam are then considered. Validated by analytical solutions, the lattice model uses two distinct postprocessing approaches to derive the energy release rates and configurational forces directly at bimaterial interface crack tips. While the first method takes advantage of the change of the lattice mesh's global stiffness matrix before and after crack growth without any stress–strain calculations to obtain crack tip driving forces, the second approach analyzes the configurational forces opposing the crack tip motion using the Eshelby stress tensor and local force balance law in cracked and heterogeneous domains. It is demonstrated that the discrete material forces at crack tips are closely equal to the tip driving forces for the three fracture problems, confirming that the lattice is an appropriate numerical tool to analyze fracture properties of evolving interface cracks. Satisfying C1 continuity by including rotational displacements for frame struts, there is also no need for the lattice to update interior computational points in the mesh to eliminate spurious material forces away from the tip.

Energy Release Rates for an Interface Crack Embedded in a Laminated Beam Subjected to Three-Point Bending

1997 ◽  
Vol 64 (2) ◽  
pp. 375-382 ◽  
Author(s):  
M. Toya ◽  
M. Aritomi ◽  
A. Chosa
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Interface Crack ◽  
Release Rate ◽  
Mode I ◽  
Mode Ii ◽  
Release Rates ◽  
Three Point Bending ◽  
Axial Forces ◽  
Energy Release Rates

Asymmetric three-point bending of a layered beam with an interface crack is analyzed on the basis of the classical beam theory. Axial forces induced by bending in the parts of the beam above and below the delamination are determined by regarding the cracked part as two lapped beams hinged at both ends. The compliance and the energy release rate are then derived. Numerical analyses based on the finite element method are carried out, which show that delamination growth occurs in mixed mode, i.e., both the normal separation (mode I) and mutual sliding (mode II) of the crack surfaces contribute to the fracturing process. Finally the decomposition of the energy release rate into mode I and mode II components is made by combining the analysis of the energy release rates by Toya (1992) and the two-dimensional linear beam solutions by Suo and Hutchinson (1990).

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