Study On Distortion Control Technology For Aero Structure Based On Slotting Method

The aero structures are easy to distort, even some are rejected, in the machining process because the inner stresses of their blank are released. Therefore, the study on distortion control technology for aero structures has important meaning. In this thesis, the slotting method used in the real production is modeled firstly, and then the relationship between the stress release and distortion release induced by slotting process are analysised, and lastly, the optimization method for the best distortion are researched and proved by simulation and experimentation based on the classical inner stress of prestretched aluminum alloy plates. The major research works are listed as follows:1. It is proved by cutting test that the distortion of parts can be induced by release of inner stresses. The results of the test also show that the inner stresses are released gradually by gradually cutting the material of blank,but the distortion is not become bigger all the time.2. The process of stresses release induced by slotting is analysised. The relationship between the stress release and distortion release are analysised by modeling the slotting method. A geometrical model is built to picture the relationship between the slotting parameters and released distortion which has there parameters including the width,depth and position of slot. The expression of bending degree is given by discuss the geometrical model.3. An idea for control the machining distortion is submit. In order to produce the best distortion which equals the normal distortion of the part, the optimization method are researched. Those optimization parameters is validated by numerical simulation and the results indicates the distortion is reduced well.4. The distortion of a frame structure is studied. The blank is 6061T651 aluminum alloy plate. its inner stresses are measured and the best parameters of slot are obtained by FEM. The real frame structure is machined using the best parameters and its distortion is measured. The distortion of the frame structure is far less then the normal one and is not over the tolerance.