Ultrasonic testing method used for composite material foaming structures

Abstract

The invention belongs to the technical field of non-destructive testing and relates to an ultrasonic testing method used for composite material foaming structures. According to the method, ultrasonic waves formed by a large number of shock pulse waves in the composite material foaming structures are utilized, and by constructing transfer functions of the ultrasonic waves in the composite material foaming structures, the arithmetical relationship between the ultrasonic waves and different part defects of the composite material foaming structures is set up to carry out defect discriminating and ultrasonic testing; the shock pulse ultrasonic waves of different types, intensities and frequencies and ultrasonic testing achieving methods can be selected, and the different composite foaming structures can be tested in an ultrasonic mode. Actual testing results show that the sensitivity, the resolution and the ability of composite material foaming structure testing are remarkably improved, the defects and the combination conditions of skin, skin / foam cementing areas, foam / foam cementing areas and foam areas can be tested accurately, the testing reliability is greatly improved, and the foam testing thickness can be 100 mm.

Description

technical field [0001] The invention belongs to the technical field of non-destructive testing and relates to an ultrasonic testing method for composite material foam structures. Background technique [0002] Composite foam structure, as an ultra-light structure, has been widely used in aerospace, transportation and other industrial fields. By selecting different composite materials and foam materials, and designing foam bonding processes with different shapes and thicknesses, it is possible to manufacture various types of structures. Composite foam structure. In order to improve the process of composite foam structure and ensure the quality of composite foam structure, non-destructive testing of composite foam structure is usually required. At present, the foam structures that need to be tested non-destructively can be divided into two categories, such as figure 2 Shown: One type is that the foam is directly bonded to the composite skin to form various composite foam stru...

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Problems solved by technology

Theoretically, currently feasible non-destructive testing methods are: (1) soft X-ray testing method, the main disadvantages of which are: 1) it is difficult to detect the defects of the foam bonding interface perpendicular to the X-ray beam orientation; 2) the detection efficiency Low cost, high cost, and special radiation protection are required; (2) The main disadvantage of conventional ultrasonic testing methods is that the sound waves attenuate sharply in the foam structure, making it difficult for the incident sound waves to propagate effectively in the foam, thus making it difficult to achieve foam and foam / Detection of foam bonding defects; (3) air-coupled ultrasonic testing method, its main shortcomings are: 1) audio pulses are mostly used to excite ultrasonic waves, and its spatial resolution is low, which is difficult to meet the requirements of skin and skin in composite foam structures. / Defect detection requirements in the foam bonding area; 2) The propagation behavior of the incident sound wave in the foam area is very close to the propagation behavior in the air, which makes it difficult to identify defects

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