Establishment method of intelligent piezoelectric aggregate mechanical model

Abstract

The invention discloses an establishment method of an intelligent piezoelectric aggregate mechanical model. The method comprises the steps that mechanical models and mathematical models of a bonded PZT sensor and an embedded PZT sensor are established through a lumped mass method on the basis of a constitutive relation of a PZT direct piezoelectric effect and a vibration principle of structural dynamics respectively; a bonded PZT driving mechanical model and an embedded PZT driving mechanical model which freely vibrate in the length direction of a monolithic PZT are established through the lumped mass method on the basis of a constitutive relation of a PZT inverse piezoelectric effect and the vibration principle of the structural dynamics. The intelligent piezoelectric aggregate has the good compression resistance, shear resistance and freezing-thawing cycle resistance and can meet the requirements of a concrete structure health monitoring technology and a concrete structure damage identification method, effectively solve the problem that at present, most monitoring technologies and damage identification methods are sensitive to measuring errors and reduce the possibility of damage misjudgment.

Description

technical field [0001] The invention belongs to the field of structural engineering, in particular to a method for establishing a piezoelectric intelligent aggregate mechanical model. Background technique [0002] Research on new theories and methods around intelligent materials and structural systems is an important theoretical basis for promoting structural health monitoring and damage diagnosis, intelligent control systems for structural vibration and disaster response, and intelligent repair systems for structural local damage. The intelligent material and structural system represented by piezoelectric materials has the superior characteristics of sensing, driving and information processing, which has opened up new ways for civil engineering structure health monitoring and damage diagnosis, and has been widely used. [0003] Although the health monitoring and damage identification technology of civil engineering structures based on piezoelectric smart sensors and drivers...

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Problems solved by technology

[0004] (1) Due to the complex boundary conditions and stress conditions of the PZT sensor, poor interface and acoustic impedance matching with the concrete upper structure, narrow frequency band response, etc., it is difficult to conduct accurate theoretical analysis, which directly affects its test accuracy and effectiveness

At present, there are two connection methods between the piezoelectric sensor and the main structure, which are embedded and pasted. No matter which connection method is used, it is assumed that the force of the PZT sensor is in a linear relationship with the output voltage, and the influence of factors such as the connection adhesive layer is considered. Less, resulting in a certain gap between the analysis results and the actual situation

At the same time, there are few in-depth studies on the combination of PZT sheet and adhesive layer and modeling theory, and the application research of piezoelectric sensors is still mainly based on device development, with many theoretical simulations and little experimental verification.

[0005] (2) In the research based on PZT driver technology, on the one hand, the PZT sheet is combined with the substrate, and the driving force is calculated by using the principle of static balance, assuming that the strain at the contact surface is equal, and considering the PZT under the action of alternating voltage There are relatively few studies on dynamic characteristics; on the other hand, in practical applications, it is difficult to accurately establish the relationship between the input signal of the driver and the driving force generated; in theoretical research, the properties of PZT materials, the bonding layer between PZT and the substrate are not considered. impact on drive

Therefore, the modeling theory and experimental research of sticky and embedded PZT drive technology are not perfect.

[0006] (3) As an embedded piezoelectric ceramic sensor and driver, only by improving its packaging and strengthening its construction protection measures, the effect of improving its service life is very limited

In the long-term continuous monitoring of the structure under load, the signal change caused by the damage of the structure may be overwhelmed by the noise signal

Only relying on occasional single monitoring data cannot fully reflect the health status of the structure, and sometimes even misjudgment occurs, which leads to the contradiction between theoretical methods and practical applications, and hinders structural health monitoring and damage based on piezoelectric smart sensors / actuators. Application of identification methods

[0008] (5) The durability and stability of the traditional monitoring system are not good, and the ability to resist electromagnetic interference is not strong. There is still a lack of theoretical and experimental research on dimensional concrete structures

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