Single-side J-integral method for interface cracks

Abstract

The invention discloses a single-side J-integral method for an interface crack. The method comprises the following steps of: S1, defining single-side J-integral, and building a calculation formula of the single-side J-integral; S2, implementing an interface shear experiment, and obtaining a displacement field / strain field of a component on one side of an interface needing J-integral calculation; S3, calculating the single-side J-integral according to the experimental data in the step S2 and the calculation formula in the step S1; and S4, establishing a unilateral J-integral interface crack instability propagation criterion so as to evaluate the propagation behavior of the interface crack and the interface damage behavior of a composite structure. According to the method, the J-integral of the interface crack with the homogeneous material on the single side can be conveniently calculated, the J-integral of the interface crack with the heterogeneous material on the single side can also be calculated. The method is also suitable for interface failure analysis of a composite structure with crack-shaped defects in different stress states.

Description

technical field [0001] The invention relates to the technical field of fracture mechanics calculation and testing, in particular to a one-sided J-integral method for interface cracks. Background technique [0002] For composite structures dominated by interface failure, such as fiber-reinforced composite (FRP) reinforced reinforced concrete (RC) members, FRP-strengthened steel structures, structures covered by thermal barrier coatings, etc., the existing evaluation models for interface failure behavior, In particular, the evaluation model of FRP-concrete / steel plate interface failure is usually based on the cohesion model of the strength theory and the interface bond-slip model. However, these models do not yet have a unified expression, and contain multiple fitting parameters, which need to be improved both in terms of calculation accuracy and convenience. Moreover, the failure process of the composite structure interface is often accompanied by the initiation and propagat...

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Problems solved by technology

However, for composite structures with possible interface damage, such as FRP-strengthened RC structures, FRP-strengthened steel structures, etc., the calculated thickness of FRP is different from the thickness of the other side components such as concrete and steel plates, and the material properties on both sides of the interface are also different. The big difference leads to great difficulties in the J-integral calculation of this type of interface crack problem, and the relevant research results have not been reported so far.

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