Measuring device and method for describing fracture toughness of FRP-concrete bond surface

Abstract

The invention discloses a measuring device and method for describing the fracture toughness of an FRP-concrete bond surface, comprising a fixing fixture, a test piece frame and a cantilever beam. In the invention, the FRP-concrete bond surface does not need preserved cracks, thereby avoiding the need for the measurement of the crack tip position in the test and the effects of the length of the preserved cracks and the tip shape on the test results. The height of the cantilever beam is along the axis of the cantilever beam, and linearly increases from the cantilever end to the trailing end. Thecross sections of the cantilever end and the trailing end are rectangular. The height of a single cantilever beam used in the invention increases linearly along the beam axis direction. During the fracture process, the flexibility of the single cantilever beam increases with the cracks, and the gradient change of the length is constant, which simplifies the calculation of the critical strain energy release rate of a type I fracture of the FRP-reinforced concrete.

Description

technical field [0001] The invention relates to a device for measuring the fracture toughness of a material fracture interface, in particular to a device and method for describing the fracture toughness of an FRP-concrete bonding surface, belonging to the field of material mechanics testing. Background technique [0002] During the service period of concrete structures, aging and environmental influences lead to a gradual decrease in the mechanical properties of the structure to a certain extent. At the same time, the sudden increase of load or the damage of accidental load may also cause the premature decline or loss of the structural bearing capacity. Compared with demolition and reconstruction, it is often more economical and reasonable to adopt appropriate reinforcement methods to improve the mechanical properties of existing concrete structures, so various reinforcement methods and reinforcement new materials have also been spawned. Among all kinds of reinforcement mat...

AI Technical Summary

Problems solved by technology

The double cantilever beam test is a traditional test method widely used to determine the fracture performance of materials, but there are a series of unavoidable problems in the fracture performance test of FRP reinforced concrete materials, for example, the fracture occurs in the cantilever due to insufficient concrete tensile strength. On the beam, the length of the reserved crack and the shape of the tip lead to different measurement results, etc.

In addition, the tip position of the crack in the double cantilever beam test must be accurately physically measured during the test, and it is very difficult to accurately measure the crack tip position

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