Nonlinear guided wave-based method for characterizing fracture toughness of aircraft composite bonded structures

By using nonlinear waveguide technology and frequency domain analysis, combined with mechanical experiments, a characterization model for interface fracture toughness was established. This solved the problem of nondestructive quantitative characterization of the bonding structure between the composite skin and the outer shell of an aircraft, and enabled nondestructive assessment and health monitoring of the fracture toughness of the bonding interface.

CN122218092BActive Publication Date: 2026-07-21EAST CHINA UNIV OF SCI & TECH
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Patent Information

Authority / Receiving Office
CN Β· China
Patent Type
Patents(China)
Current Assignee / Owner
EAST CHINA UNIV OF SCI & TECH
Filing Date
2026-05-15
Publication Date
2026-07-21

AI Technical Summary

Technical Problem

Existing technologies make it difficult to non-destructively and quantitatively characterize the interfacial fracture toughness of the bonding structure between the composite skin and the outer shell of an aircraft without destructive testing. Traditional methods are also unable to reflect the mechanical state of the actual structure.

Method used

Nonlinear waveguide technology is employed to acquire waveguide signals and perform frequency domain analysis by applying waveguide excitation. The amplitudes of the second and third harmonics are extracted, nonlinear parameters are calculated, and an interface fracture toughness characterization model is established in conjunction with mechanical experiments. An interface evolution index is introduced for nondestructive evaluation.

Benefits of technology

This technology enables non-destructive quantitative characterization of the fracture toughness of the bonding interface, allowing for the assessment of the interface health status without compromising structural integrity. It provides technical support for non-destructive testing and health monitoring of aircraft composite bonding structures.

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Abstract

The present application relates to the technical field of non-destructive characterization of composite material interface, and provides a method for characterizing fracture toughness of aircraft composite bonding structure based on nonlinear guided waves, which comprises applying nonlinear guided wave excitation to the bonding structure of the aircraft composite skin and shell to be tested, collecting the first-arriving guided wave signals propagating along the bonding interface in each bonding sample to be tested; performing frequency domain analysis on the first-arriving guided wave signals on each propagation path, extracting the amplitudes of the fundamental frequency component, the second harmonic component and the third harmonic component, calculating the corresponding nonlinear parameters and the normalized nonlinear parameters; solving the corresponding interface evolution index by using the constructed bonding interface fracture toughness characterization model; converting the obtained interface evolution index into interface fracture toughness according to the mapping relationship between the interface evolution index and the type I interface fracture toughness established by experiments, and realizing the non-destructive fracture toughness characterization of the bonding sample to be tested.
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