Rapid nondestructive testing method for large-size composite material and sandwich structure of large-size composite material

Abstract

The invention relates to a rapid nondestructive testing method for a large-size composite material, which is characterized by comprising the following steps: randomly sampling according to a standard component to obtain a rapid sparse representation vector of a defect-free reference signal sample set; performing fast sparse characterization, the sparse characterization of the reference signal and the sampling signal adopting parallel noise reduction and sparse representation of signal singularity measurement based on a wavelet domain modulus maximum value, feature clustering of a nonlinear support vector machine, an adaptive observation model of correlation entropy and normalization of a Sigmoid function; using a maskless compressed sensing (CS) topological distribution optimization strategy of a correlation entropy adaptive model, and characterizing a result and the correlation entropy adaptive model rapidly; judging the homogeneity and heterogeneity of signals through weighting, designing a structured measurement matrix easy to store under a CS theoretical framework in combination with a block random form of a structured thought, and providing effective data for reconstruction after rapid detection. The method is closely related to detection object parameters, the implementation method is simple and easy to implement, and the engineering practicability is high.

Description

technical field [0001] The invention belongs to the field of non-destructive testing of composite materials and their sandwich structures, and specifically relates to a rapid non-destructive testing method for large-scale composite materials and their sandwich structures. Background technique [0002] The excellent properties of composite materials and their sandwich structures in terms of mechanics, processing and forming have made them highly respected in the field of aerospace and become an indispensable and important component of key components such as aviation, aerospace, and radio astronomy. Therefore, accurate non-destructive assessment of its defects and damage is very important. However, compared with metal structures, on the one hand, due to the complex nature of composite materials, the causes of fatigue and fracture are less well understood than metal structures, and the detection of defects or damage targets that are closely stacked or complex in sandwich struct...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a fast terahertz nondestructive testing method for large-scale composite materials and their sandwich structures. Feature sparsification, adaptive identification, compressed sampling data volume and acquisition time to achieve fast non-destructive detection

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