Non-uniform material dispersion crack J integration method based on fracture phase field method

Abstract

The invention discloses a non-uniform material dispersion crack J integral method based on a fracture phase field method, and the method comprises the following steps: 1, introducing a phase field variable d of a fracture phase field model, and determining a non-uniform material dispersion crack J integral expression with integral region independence and a corresponding finite element discrete format; 2, establishing a finite element model containing dispersion cracks and dividing finite element grids; 3, calling a calculation subprogram of the fracture phase field model, and solving a nonlinear control equation of the fracture phase field model by adopting a Newton-Raphson method; and 4, according to a finite element discrete format of the J integral of the dispersion crack of the non-uniform material, solving a characteristic quantity-stress intensity factor KI of the dispersion crack tip based on a finite element calculation result. According to the method, the characteristic quantity of the dispersion crack tip of the non-uniform material is accurately solved, and the defect that the stress state of the dispersion crack tip cannot be accurately described by a traditional fracture phase field method is overcome.

Description

technical field [0001] The invention belongs to the technical field of computer simulation, and relates to a method for solving the fracture problem of non-uniform materials, in particular to a J-integral method for diffuse cracks of non-uniform materials based on the fracture phase field method. Background technique [0002] Inhomogeneous materials (such as functionally graded materials, composite materials, etc.) have the advantages of different component properties, and have designability that is difficult to match with traditional materials. They are more and more widely used in my country's high-end equipment fields such as aviation and aerospace. The fracture failure of heterogeneous materials is usually the result of comprehensive damage effects such as initial damage evolution, crack nucleation, and crack instability propagation. However, the existing fracture mechanics theory is still stretched and even bottlenecked in describing their fracture failure behavior. Com...

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Problems solved by technology

Just limited by the above two characteristics, the fracture phase field method cannot accurately capture the crack tip position on the one hand, so it is difficult to effectively extract the crack tip feature quantity; on the other hand, the influence mechanism of the phase field evolution equation on the law of diffuse crack propagation is not clear

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