Method and system for monitoring rigidity damage of structure based on EMD

Abstract

The present invention discloses a method and system for monitoring rigidity damage of a structure. The method comprises the steps of: monitoring vibration responses of the structure and obtaining acceleration response signals of the structure; performing EMD decomposition for the acceleration response signals, determining first IMF component gradients at any time, and calculating monitoring factors at different positions of the structure; rejecting false monitoring factors by using a constrained condition, wherein the monitoring factors and rigidity damage degrees of the structure have a linear relation; determining the time when the rigidity damage of the structure occurs according to features of the monitoring factors changing over time, and determining the position where the damage occurs by comparing distribution of the monitoring factors at different positions of the structure; and determining the rigidity damage degree of the structure according to an amplitude of the monitoring factor corresponding to the time when the rigidity damage occurs. The method of the present invention is especially suitable for monitoring and determining tiny rigidity damage of the structure under the effect of impact loading, can accurately identify the tiny rigidity damage, has a good anti-noise capability, can determine the damage degree by calculating the amplitude of the monitoring factor, and has a high application value.

Description

technical field [0001] The invention relates to a structural stiffness damage monitoring method based on EMD (empirical mode decomposition algorithm). The invention also relates to an EMD-based structural stiffness damage monitoring system dedicated to the above method. Background technique [0002] The safe service of engineering structures under external loads and environments is of great significance. At present, more and more large-scale high-rise towering structures, long-span bridges and long-span space structures are appearing at home and abroad. Due to the harsh natural environment and strong external loads, engineering structures inevitably experience damage accumulation and cause performance degradation and damage damage. Strong external loads, earthquake action, and blast impact loads can easily cause performance degradation of engineering structures, and then lead to sudden changes in the stiffness of the structure, such as welding fractures, component buckling...

AI Technical Summary

Problems solved by technology

[0005] (1) Usually only a large degree of structural stiffness damage (such as above 10%) can be identified, and the recognition effect for small structural stiffness damage (such as below 5%) is very unstable, depending on the characteristics of the structure itself and external loads characteristics

[0006] (2) Only the location and time of sudden stiffness damage can be identified, but the degree of mutation damage cannot be quantitatively determined

Therefore, it can only be identified qualitatively but not quantitatively, which is a major defect of the current method

[0007] (3) The current method cannot effectively identify the small stiffness damage of the structure under the impact load

Because the damage signal is too weak, it is impossible to judge the time and location of the damage, let alone the degree of damage

[0008] (4) The current method is not strong in anti-interference ability to noise

Damage events cannot be effectively monitored at all after minor stiffness damage to the structure

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