Nonlinear ultrasonic evaluation device and method for surface damage of concrete material

Abstract

The invention discloses a nonlinear ultrasonic evaluation device and method for surface damage of a concrete material. A concrete test piece to be tested is put into the loading end and both ends thereof are fixed, an ultrasonic probe is placed at a set position on the surface of the test piece; a high-energy pulse signal output end of the non-linear acoustic detection equipment is amplified; theair coupling transducer is specially arranged and interacts with the ultrasonic transducer, Rayleigh waves are excited on the surface and propagated in the test piece, then ultrasonic signals are received by the specially arranged air coupling transducer, nonlinear ultrasonic parameters are obtained through signal processing, and the nonlinear ultrasonic parameters can effectively reflect the damage to the test piece. According to the invention, on-line monitoring of damage in the loading process of the concrete material can be realized; the test piece does not need to be taken down from the loading table during damage measurement; therefore, the mechanical condition of the in-service component under the action of the external reciprocating load can be accurately evaluated, the risk causedby fracture failure of the concrete component due to damage is reduced, the defects that existing equipment is inconvenient to operate and cannot be monitored in the loading process are overcome, andthe method has commercial application and popularization value.

Description

technical field [0001] The invention relates to concrete testing technology, in particular to a nonlinear ultrasonic evaluation device and method for surface damage of concrete materials. Background technique [0002] Concrete components widely used in engineering structures, due to long-term loading and external environmental influences (such as weathering, freeze-thaw, etc.), will cause internal damage to the material and local micro-crack expansion, resulting in the degradation of the mechanical properties of the structure. After a certain degree of damage accumulation, the structure may suddenly be brittle, resulting in serious engineering accidents. Studies have shown that the load on the structure plays a vital role in the initiation and propagation of cracks, and in practical engineering, most of the structures will be subjected to cyclic loads, and fatigue brittle fracture is often prone to occur under such conditions . The diagnosis of early structural degradation...

AI Technical Summary

Problems solved by technology

However, this method is complicated and time-consuming, and it will cause large signal fluctuations due to the acoustic difference between the wedge transducer receiving the signal and the surface of the test piece

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