Ultrasonic imaging detection method of honeycomb sandwich structure based on automatic scanning

Abstract

The invention belongs to the technical field of nondestructive detection, and relates to an automatic scanning-based cellular core sandwich structure ultrasonic imaging detection method. The method is characterized in that defect discrimination and ultrasonic imaging are carried out through establishing corresponding transition functions by using the reflection echo signals of incident pulse ultrasonic waves with different wavelengths in a sheath / cellular core connecting layer, a cellular core connecting layer / cellular wall and a cellular core connecting layer / cellular grid interface. Ultrasonic automatic scanning imaging detection of different cemented and welded cellular core sandwich structures is realized through selecting different incident pulse ultrasonic wave frequencies, an energy transducer and an acoustic beam diameter thereof, scanning stepping, acoustics coupling modes and ultrasonic automatic scanning devices. A practical detection effect shows that the method greatly improves the detection sensitivity and resolution and the detection ability of a cellular core structure, allows defects and combination conditions between the sheath / cellular core, the sheath / connecting layer and the connecting layer / cellular grid, and greatly improves the detection reliability.

Description

Technical field [0001] The invention belongs to the technical field of nondestructive testing, and relates to an ultrasonic imaging detection method for a honeycomb sandwich structure based on automatic scanning. Background technique [0002] As the composite honeycomb sandwich structure and metal honeycomb sandwich structure are widely used in aerospace, transportation and other industrial fields, they are usually manufactured into various honeycomb sandwich structures by processes such as gluing and welding, which need to be applied to the machine. The honeycomb sandwich structure is automatically scanned and non-destructively tested to ensure the quality and service safety of the installed structure. At present, there are mainly two detection methods: (1) X-ray digital imaging detection method. Its main disadvantages are: 1) Only the defects of the honeycomb core itself can be detected, and it is difficult to detect the defects of the skin / honeycomb core connection interface. ...

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Problems solved by technology

At present, two detection methods are mainly used: (1) X-ray digital imaging detection method, its main disadvantages are: 1) It can only detect the defects of the honeycomb core itself, and it is difficult to detect the defects of the skin / honeycomb core connection interface ; 2) The cost is high; 3) Strict radiation protection is required; 4) It is not environmentally friendly; (2) Ultrasonic testing methods mostly use the penetration method for testing. The resolution is low, and it is difficult to obtain the connection between each honeycomb core and the skin; 2) For a large-thickness honeycomb core, due to the extremely severe sound wave attenuation, it is difficult to detect; 3) The transducer needs to be detected from both sides of the part Parts, which require a complex synchronous scanning mechanism and strict water spray coupling control and water purification requirements; 4) The depth position of the detected defect cannot be determined

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