Anti-plane fracture problem of three nano-cracks emanating from a magnetoelectrically permeable regular triangle nano-hole in magnetoelectroelastic materials

2020 ◽  
pp. 2150127
Author(s):  
Dongsheng Yang ◽  
Guanting Liu
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Release Rate ◽  
Magnetic Induction ◽  
Surface Effect ◽  
Electric Displacement ◽  
Magnetoelectroelastic Materials ◽  
Electric Displacement Intensity Factor ◽  
Magnetic Induction Intensity

Based on the Gurtin–Murdoch surface/interface model and complex potential theory, by constructing a new conformal mapping, the anti-plane fracture problem of three nano-cracks emanating from a magnetoelectrically permeable triangle nano-hole in magnetoelectroelastic materials with surface effect is studied. The exact solutions of the stress intensity factor, the electric displacement intensity factor, the magnetic induction intensity factor, and the energy release rate are obtained under the boundary conditions of magnetoelectrically permeable and impermeable. The numerical examples show the influence of surface effect on the stress intensity factor, the electric displacement intensity factor, the magnetic induction intensity factor, and the energy release rate under two different boundary conditions. It can be seen that the surface effect leads to the coupling of stress, electric and magnetic field, and with the increase of cavity size, the influence of surface effect begins to decrease until it tends to classical elasticity theory.

scholarly journals Antiplane Fracture Problem of Three Nanocracks Emanating from an Electrically Permeable Hexagonal Nanohole in One-Dimensional Hexagonal Piezoelectric Quasicrystals

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Dongsheng Yang ◽  
Guanting Liu
Keyword(s):  
Stress Intensity ◽  
Intensity Factor ◽  
Boundary Conditions ◽  
Energy Release Rate ◽  
Release Rate ◽  
Surface Effect ◽  
Electric Displacement ◽  
One Dimensional ◽  
Phonon Field ◽  
Electric Displacement Intensity Factor

Based on the Gurtin-Murdoch surface/interface model and complex potential theory, by constructing a new conformal mapping, the electrically permeable boundary condition with surface effect is established, and the antiplane fracture problem of three nanocracks emanating from a hexagonal nanohole in one-dimensional hexagonal piezoelectric quasicrystals with surface effect is studied. The exact solutions of the stress intensity factor of the phonon field and the phason field, the electric displacement intensity factor, and the energy release rate are obtained under the two electrically permeable and the electrically impermeable boundary conditions. The numerical examples show the influence of surface effect on the stress intensity factors of the phonon field and the phason field, the electric displacement intensity factor, and the energy release rate under the two boundary conditions. It can be seen that the surface effect leads to the coupling of the phonon field, phason field, and electric field, and with the decrease of cavity size, the influence of surface effect is more obvious.

Fracture Analysis of Magnetoelectroelastic Composite Materials

2007 ◽  
Vol 348-349 ◽  
pp. 69-72 ◽  
Author(s):  
R. Rojas-Díaz ◽  
Felipe García-Sánchez ◽  
Andrés Sáez ◽  
Chuan Zeng Zhang
Keyword(s):  
Intensity Factor ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Electric Displacement ◽  
External Boundary ◽  
Loading Conditions ◽  
Magnetoelectroelastic Materials ◽  
Electric Displacement Intensity Factor ◽  
Total Energy Release Rate

This paper presents a crack analysis of linear magnetoelectroelastic materials subjected to static loading conditions. To this end, an efficient boundary element method (BEM) is developed. Unlike many previous investigations published in literature, two-dimensional (2-D) linear magnetoelectroelastic materials possessing fully coupled piezoelectric, piezomagnetic and magnetoelectric effects are considered in this paper. A combination of the displacement BEM and the traction BEM is used in the present formulation. The displacement BEM is applied for the external boundary of the cracked solid, while the traction BEM is used for the crack-faces. A regularization technique is implemented to compute the strongly singular and hypersingular boundary integrals in the BEM. The electric displacement intensity factor (EDIF), the magnetic induction intensity factor (MIIF), the stress intensity factors (SIF), the mechanical strain energy release rate (MSERR) and the total energy release rate (TERR) are evaluated directly from the computed nodal values at discontinuous quarter point elements placed next to the crack tip. The accuracy of the BEM is verified by analytical solutions known in literature. Results are presented for a branched crack in a bending specimen subjected to combined magnetic-electric-mechanical loading conditions.

Surface effect on two nanocracks emanating from an electrically semi-permeable regular 2n-polygon nanohole in one-dimensional hexagonal piezoelectric quasicrystals under anti-plane shear

2021 ◽  
Author(s):  
Zhilin Wu ◽  
Guanting Liu ◽  
Dongsheng Yang
Keyword(s):  
Stress Intensity ◽  
Intensity Factor ◽  
Surface Effect ◽  
Mechanical Load ◽  
Electric Displacement ◽  
Relative Size ◽  
Size Change ◽  
One Dimensional ◽  
Phonon Field ◽  
Electric Displacement Intensity Factor

In this paper, the conformal mapping from a regular 2[Formula: see text]-polygon hole with two collinear asymmetric cracks into a circle is constructed. Based on the Gurtin–Murdoch surface/ interface model and complex potential theory, two collinear asymmetric nanocracks emanating from an electrically semi-permeable regular 2[Formula: see text]-polygon nanohole embedded in an infinite one-dimensional hexagonal piezoelectric quasicrystals with surface effect are investigated. The size-dependent stress intensity factors of phonon field and phason field, electric displacement intensity factor at the nanocrack tip are derived for electrically semi-permeable boundary condition. Numerical examples are illustrated to show that the size of the hole, mechanical load, electric load, cracks relative size change with stress intensity factor of phonon field and electric displacement intensity factor. Also analyzed the change of the electric displacement intensity factor with different electric permeability at the nanocrack tip and the dimensionless intensity factor with [Formula: see text].

Self-Similar Interfacial Crack Growth in Anisotropic Material Under Anti-Plane Shear

1998 ◽  
Vol 14 (1) ◽  
pp. 17-22
Author(s):  
Kuang-Chong Wu
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Release Rate ◽  
Anisotropic Material ◽  
Constant Velocity ◽  
Interfacial Crack ◽  
Plane Shear ◽  
Dynamic Propagation ◽  
Self Similar

ABSTRACTDynamic propagation of a crack along the interface in an anisotropic material subjected to remote uniform anti-plane shear is studied. The crack is assumed to nucleate from an infinitesimal microcrack and expands with a constant velocity. Explicit expressions for the stress intensity factor and the energy release rate are derived.

Study on the Stress Intensity Factor for Mixed Mode Surface Crack under Three Point Bending

2008 ◽  
Vol 33-37 ◽  
pp. 85-90
Author(s):  
Wei Xie ◽  
Qi Qing Huang ◽  
Masanori Kikuchi
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Energy Release Rate ◽  
Crack Closure ◽  
Release Rate ◽  
Mixed Mode ◽  
Three Point Bending ◽  
Closure Method

In the virtual crack closure method (VCCM), the energy release rate is computed based on the results of finite element calculation, and the stress intensity factor (SIF) is computed from the energy release rate. In this paper, the stress intensity factor of mixed-mode surface cracks under three point bending is studied by using the three dimensional modified virtual crack closure method (MVCCM). The modified virtual crack closure method is required to open one element face area whose shape is arbitrary and finite element widths are unequal across the crack front. The effect of the distance between the location of load and crack face, crack shape and crack depth to the stress intensity factor is also discussed, along with practical results and conclusions.

scholarly journals Combined Effect of Pressure and Shear Stress on Penny-Shaped Fluid-Driven Cracks

2018 ◽  
Vol 85 (3) ◽  
Author(s):  
Wenhao Shen ◽  
Ya-Pu Zhao
Keyword(s):  
Stress Intensity Factor ◽  
Shear Stress ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Propagation ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Crack Opening ◽  
Effect Of Pressure

Penny-shaped fluid-driven cracks are often detected in many fluid–solid interaction problems. We study the combined effect of pressure and shear stress on the crack propagation in an impermeable elastic full space. Boundary integral equations are presented, by using the integral transform method, for a penny-shaped crack under normal and shear stresses. The crack propagation criterion of stress intensity factor is examined with the strain energy release rate. Dominant regimes are obtained by using a scaling analysis. Asymptotic solution of the toughness-dominant regime is derived to show the effect of shear stress on the crack opening, crack length, and pressure distribution. The results indicate that a singular shear stress can dominate the asymptotic property of the stress field near the crack tip, and the stress intensity factor cannot be calculated even though the energy release rate is finite. Shear stress leads to a smaller crack opening, a longer crack, and a slightly larger wellbore pressure. A novel dominant-regime transition between shear stress and pressure is found. Unstable crack propagation occurs in the shear stress-dominant regime. This study may help in understanding crack problems under symmetrical loads and modeling fluid–solid interactions at the crack surfaces.

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