By using stress strength factors considering crack surface turning instead of those nonconsidering crack surface twist,on the basis of maximum strain criterion within a small range of yield strength,the critical crack length of the Ⅰ Ⅲ comopsite crack is estimated. The residual life of Ⅰ Ⅲ composite crack is then estimated. The experiment shows that this estimation method can be used for engineering.

Assuming the working face in the strip extraction as a series of co-linear cracks with certain spacing interval,the Ⅰ-Ⅱ composite crack model in fracture mechanics was adopted to get the stress distribution at the edge of coal pillar,so the border equation of the edge of coal pillar was created. Accordingly the formula for calculating damaged width of the strip coal pillar was obtained.

By using stress strength factors considering crack surface turning instead of those nonconsidering crack surface twist,on the basis of maximum strain criterion within a small range of yield strength,the critical crack length of the Ⅰ Ⅲ comopsite crack is estimated. The residual life of Ⅰ Ⅲ composite crack is then estimated. The experiment shows that this estimation method can be used for engineering.

Assuming the working face in the strip extraction as a series of co-linear cracks with certain spacing interval,the Ⅰ-Ⅱ composite crack model in fracture mechanics was adopted to get the stress distribution at the edge of coal pillar,so the border equation of the edge of coal pillar was created. Accordingly the formula for calculating damaged width of the strip coal pillar was obtained.

Designers, usually, only consider the whole stability of body-foundation of the dam after setting base joint, while ignore the stability of base joint itself. In this paper, the method of fracture finite element was applied, by applying Williams's formula I calculated the stress intensity factor of base joint after knowing the displacement field of tip of base joint then distinguished the stability of base joint by terms of composite crack's K fracture criterion.

The problem of a composite crack interacting with a circular misfitting inclusion in an infinite elastic medium is investigated.

The interacting stress field around a composite crack with a misfitting inclusion

A fracture mechanics analysis of the crack-bridging in an uniaxially fiber reinforced composite ispresented. The integral equation governing bridge-toughening as well as crack opening displacementCOD) for the composite with a power law hardening plastic interphase are constructed based on thereference [2]. Numerical results of the COD equation etc. are obtained by means of iteration-solutionmethod of the nonlinear Volterra integral equation. The effect of inter facial parameters on the toughening of composite...

A fracture mechanics analysis of the crack-bridging in an uniaxially fiber reinforced composite ispresented. The integral equation governing bridge-toughening as well as crack opening displacementCOD) for the composite with a power law hardening plastic interphase are constructed based on thereference [2]. Numerical results of the COD equation etc. are obtained by means of iteration-solutionmethod of the nonlinear Volterra integral equation. The effect of inter facial parameters on the toughening of composite crack-bridging is discussed in detail.

In the category of elastodynamic fracture, the present paper investigates the problem of SH-wave scattering by cracks of any limited lengths originating at the boundary of a cylindrical hole, and gives the solutions of dynamic stress intensify factor at the crack tip. The Green's Function method is used. That means a special Green's function, which is a fundamental solution of displacement field for an elastic half space possessing a half cylindrical gap while bearing out of plane harmonic line source force...

In the category of elastodynamic fracture, the present paper investigates the problem of SH-wave scattering by cracks of any limited lengths originating at the boundary of a cylindrical hole, and gives the solutions of dynamic stress intensify factor at the crack tip. The Green's Function method is used. That means a special Green's function, which is a fundamental solution of displacement field for an elastic half space possessing a half cylindrical gap while bearing out of plane harmonic line source force at any point of its horizontal boundary, is constructed for the present problem. In terms of the solution of SH wave scattering by a cylindrical hole, the material is divided into two parts along X axis and cracks can be made out with crack-division technique. There are two important steps in the technique of crack division. On one hand, anti plane stresses, which are the same in quantity but opposite in direction to those produced by SH waves mentioned before, are loaded at the region where cracks will appear. If the region begins at hole edge and extends to a limited distance, the composite crack is made out in the medium. On the other hand, anti plane stresses that are unknown must be applied in the non crack region of division interface in order to satisfy the continuity conditions at division plane. Then, integral equations for solution of the unknown stresses, which is connected with crack tip DSIF, can be established, and the solution of dynamic stress intensity factor in mode III can be obtained. Finally, some examples and results for dynamic stress intensity factor are given, and the influence of circular hole to dynamic stress intensity factor at crack tip is discussed. It is indicated that the traditional opinion about composite crack simplification is not right in dynamic case. Simplifying composite crack to Griffith linear crack is not always safety in dynamic fracture.

By using stress strength factors considering crack surface turning instead of those nonconsidering crack surface twist,on the basis of maximum strain criterion within a small range of yield strength,the critical crack length of the Ⅰ Ⅲ comopsite crack is estimated.The residual life of Ⅰ Ⅲ composite crack is then estimated.The experiment shows that this estimation method can be used for engineering.