Reinforced concrete structure crack trend calculation method based on moment tensor

Abstract

The invention discloses a reinforced concrete structure crack trend calculation method based on a moment tensor, and the method comprises the steps: applying a load to a reinforced concrete flexural member, collecting an acoustic emission signal when a crack is generated, and reading the amplitude of P-wave initial motion in a signal waveform received by a sensor; analyzing characteristic values of the moment tensors of different crack types based on mathematical analysis and a mechanical model, and establishing a crack type judgment standard; substituting the collected crack amplitude into amoment tensor equation set to obtain a moment tensor of the corresponding crack; normalizing the fracture moment tensor characteristic value, and judging the fracture type according to a fracture typejudgment standard; and calculating a feature vector corresponding to the crack moment tensor feature value, calculating a motion vector of the crack according to the feature vector, and determining an included angle between the motion vector and a coordinate axis, thereby determining the crack trend. According to the method, the position and trend of the stress crack of the reinforced concrete member can be determined, and a new way is provided for reinforced concrete structure health monitoring and disaster early warning.

Description

technical field [0001] The invention belongs to the technical field of acoustic emission monitoring, in particular to a method for calculating the direction of cracks in reinforced concrete structures based on moment tensor. Background technique [0002] Acoustic emission (AE) testing technology is an important dynamic non-destructive testing method, which mainly judges the damage degree inside the structure by collecting the instantaneous elastic wave generated by the rapid release of local strain energy inside the material. Reinforced concrete structures are currently the most widely used building structures, and the importance of non-destructive testing of in-service reinforced concrete structures has become increasingly prominent. Combining the theory of moment tensor inversion of seismic source mechanism in seismology with the acoustic emission method in non-destructive testing, and introducing it to the damage mechanism of reinforced concrete structural materials or st...

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Problems solved by technology

Combining the theory of moment tensor inversion of seismic source mechanism in seismology with the acoustic emission method in non-destructive testing, and introducing it to the damage mechanism of reinforced concrete structural materials or structures, the moment tensor and acoustic emission waveform can be established The method and steps for determining the direction of structural cracks based on data are mainly based on different types of cracks, the geometric relationship between the motion vector and the normal vector is different, and the direction of the crack and the relationship between the motion vector and the normal vector can be obtained by the addition and subtraction of the eigenvectors. Vector value, the vector obtained by this method can represent the direction of the fracture, but most of the current research is limited to the calculation of the eigenvectors to mark the corresponding fracture direction in the coordinate system, so in order to directly determine the direction of the fracture, it is necessary to determine The angle between the crack direction and the coordinate axis can be used to visually judge the crack direction

[0003] Both at home and abroad, most of them analyze the damage mechanism of concrete qualitatively, and the method of using AE technology to analyze and evaluate the damage mechanism of materials or structures from a quantitative perspective is basically blank in China, and there is no public report; although there are foreign countries that involve quantitative analysis, However, the qualitative analysis theory is not mature enough, the theoretical methods are not perfect, and some quantitative methods are complicated to operate, the workload is large, and quantitative analysis cannot be performed.

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