Active monitoring and evaluating method for directional damage of engineering structure

Abstract

The invention discloses an active monitoring and evaluating method for directional damage of an engineering structure.The active monitoring and evaluating method includes the steps that multiple linear piezoelectric actuating / sensing arrays are arranged around regions, to be detected, on the structure to be detected so that the regions of the whole structure to be detected can be covered after the scanning and monitoring ranges of all the arrays are combined; Lamb wave standard response signals of all actuating / sensing channels of all the arrays in a healthy state of the structure and Lamb wave response signals in a damaged state are collected and subjected to subtraction to extract damage scattered signals; according to coherence between the damage scattered signals and phases thereof, damage direction information and the position of a main actuator are obtained through calculation, directional damage is imaged to obtain damage position and length, and then the health condition of the structure to be monitored is analyzed and judged.By means of the method, monitoring accuracy of direction damage such as cracks and structural fracture can be improved, and structural safety is guaranteed.

Description

technical field [0001] The invention relates to a method for active Lamb wave damage monitoring of plate engineering structures, in particular to an active monitoring and evaluation method for directional damage of engineering structures based on piezoelectric excitation / sensing linear arrays. Background technique [0002] With the continuous improvement of structural safety and reliability requirements, the on-line monitoring and evaluation of structural damage has attracted more and more attention. For example, in the field of new energy wind power generation, in the large-scale wind farms built in various parts of my country in recent years, the structure of the fan blades has been in harsh natural environments for a long time, and is vulnerable to erosion by sandstorms, ultraviolet rays, rain and snow, and damage. In order to prevent disasters or losses caused by structural damage, it is necessary to effectively monitor the structure and evaluate the expansion of damage ...

AI Technical Summary

Problems solved by technology

However, most of the existing Lamb wave structural damage monitoring technology researches use the distributed piezoelectric actuator / sensor array method to improve the monitoring efficiency, but it is restricted by factors such as signal propagation direction and damage scattering angle. It is difficult to extract information related to the damage direction, so it can only realize the diagnosis and evaluation of damage location and approximate range, and it is difficult to provide diagnostic evaluation results such as the direction, length, and expansion trend of cracks and other damage; ultrasonic phased array When the technology is applied to Lamb wave structural damage monitoring, due to strict restrictions on the distance between the exciter / sensor in the array, the linear array is a dense array, which is limited by the number of acquisition channels of the monitoring system and the geometric characteristics of the structure to be measured. , the length of the array is limited, and the reflection or scattering signal generated by the directional damage has a certain angle, which often cannot return to the array with a limited length, resulting in no damage detection. At the same time, the damage monitoring results given by the ultrasonic phased array monitoring technology It can only be judged that there is damage at a certain distance from the array in a certain direction, and it is impossible to distinguish whether the damage has directionality and whether there is further expansion, etc.

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