Ultrasonic Detection Path Generation Method And System Development Of Deformed Aero Fan Blades

The third generation wide chord hollow fan blade is the core component of high performance civil aero engine.Because the aero-engine fan blade is located in the front of the aero-engine,it not only needs to run under the harsh conditions of high pressure and high speed,but also needs to deal with the impact of hail,birds and even metal.In order to ensure the safety of flight,it is necessary to conduct nondestructive testing on the blade to ensure its reliable quality.The defects of the third-generation wide-chord hollow fan blades are mainly concentrated on the internal structural surface,so ultrasonic testing is generally used to conduct non-destructive testing on the internal structural surface of aviation blades.It is difficult to measure the shape of inner structure surface directly because of the large deformation of aircraft blade in the process of machining.Therefore,the current ultrasonic detection method can not guarantee the accurate ultrasonic focus on the internal structure surface,and may lead to the collision between the ultrasonic probe and blade parts.How to realize automatic ultrasonic detection of deformed aero blades is a realistic and urgent topic in the field of aviation industry.This paper will take "developing a set of software to solve three problems" as the main line to carry out the research on automatic generation method of ultrasonic detection path of the third generation wide chord hollow fan blade of aeroengine.The main research work of this paper is as follows:(1)By studying the machining technology of the third generation wide chord hollow fan blade,the alignment algorithm of the theoretical CAD model of the aero-blade and the measuring point cloud model that is suitable for the machining technology is proposed,which solves the attitude deviation problem of the deformed aero-blade CAD model and the point cloud model due to the different reference coordinate system.It lays a foundation for further estimating the shape of structural surface in aircraft blade parts by FFD(Free-Form Deformation).(2)By studying FFD technology and geometric modeling technology of fan blade CAD model,based on the FFD of surface structure within the fan blade shape estimation algorithm,to solve the deformation after the fan blade structure surface shape is difficult to directly measure the problem,in order to further generated within the aviation blade structure surface ultrasonic testing path lay the foundation.(3)By studying the principle of ultrasonic detection,the algorithm of ultrasonic detection path generation for internal structural surface of deformed aero-blade was realized,which solved the problem of ultrasonic probe automatic shape scanning for internal structural surface of deformed fan blade,and laid a foundation for automatic processing of ultrasonic detection data and automatic analysis of defects.(4)A set of ultrasonic detection path generation system for aircraft blades was developed and the function of the system was verified by a complete example of ultrasonic detection path generation for deformed aircraft blades,which effectively improved the detection quality and automation level of ultrasonic detection of fan blade internal structure surface.