Design Of Ultrasonic Energy Guidance Device Based On CFRP Structure Damage Detection

With the extensive use of carbon fiber composite in aerospace and other engineering fields,the nondestructive testing technology of composite materials has been greatly developed,in which the power ultrasonic infrared thermal image testing technology has attracted much attention due to its advantages of rapid detection and intuitive detection effect.It has been proved that the power ultrasonic infrared detection technology can effectively detect the delamination,crack and impact damage in composite materials.However,due to the need to apply a large contact force between the ultrasonic horn and the test sample in the detection process,secondary impact damage is easy to occur at the excitation position.Due to the influence of the shape of the excitation surface of the ultrasonic horn,it has no guidance to the ultrasonic energy,low utilization rate of the ultrasonic energy and is not suitable for the damage detection of complex shape composite structures,so it is of great significance to design a power ultrasonic energy guidance device.The main research contents of this paper include four parts:1)The development status of composite materials nondestructive testing technology and ultrasonic infrared thermal imaging technology are introduced.The significance of ultrasonic energy directivity and design of ultrasonic excitation device was expounded.The research background and the main research contents of the thesis are given.2)The principle of ultrasonic testing,ultrasonic excitation system and the design basis of ultrasonic horn are described.The vibration collision model and ultrasonic interference fitting model of ultrasonic excitation device and sample are established.The interference effect of two ultrasonic wave sources is analyzed,in order to provide theoretical basis for the design of ultrasonic energy guide device in the following chapters.3)Based on the finite element simulation software ABAQUS,this paper analyzes the ultrasonic energy guidance of contact surfaces with different shapes,and proposes a design method of ultrasonic energy guidance device combined with ultrasonic interference theory and power ultrasonic infrared technology characteristics.A simulation model of CFRP tube with through crack is established,and the characteristics of damage and heat generation under the excitation of ultrasonic energy guide device and ultrasonic horn are compared and analyzed.The effects of direction and location of through crack on ultrasonic energy transmission and damage and heat generation are also analyzed.In this paper,the damage and heat generation characteristics of flat plate crack under the excitation of ultrasonic energy guide device and ultrasonic horn are compared and analyzed.According to the shape characteristics of composite pipe fittings,an arc-shaped ultrasonic energy guide device is designed,and the influence of the direction of through crack and the position of excitation on the ultrasonic energy transmission and damage and heat generation is analyzed.4)On the basis of simulation and analysis,the ultrasonic energy guide device is customized,and the CFRP flat specimen with central through crack,delamination damage and the CFRP round tube specimen with through crack and impact damage are made.The effect of power ultrasonic energy guide device and ultrasonic horn damage detection is compared and analyzed,and the direction of CFRP flat and round tube through crack is studied The influence of different excitation positions on the damage heat generation.