The Numerical Simulation Study On Machining Deformation Of The Aeronautic Thin-walled Structure Components

For the large size, complex structure, high accuracy of aeronautic structure components, and the low rigidity with 1.5-3mm thickness, even below 1.5 mm for the thin walled Structure Components, the deformation of bending, torsion or combination of bending and torsion may be caused, which make the aeronautic structure components not satisfy the design requirements, even turn into wasters, so the problem of machining deformation affects the throughput and operating costs of astronautic products seriously. On the basic description of the aeronautic components in home and abroad, A more in-depth study on milling deformation forecast for the overall structure of the aeronautic product is made through the residual Stress by methods of theoretical analysis, finite element numerical simulation, and comparison with known Experiments.(1) First of all, Based on the elastic-plastic mechanics theory, this article deduces the modified layer-removal strain method adapting the internal residual stress in thick pre-stretched aluminum plate by considering two different strain situations, which are caused by Tensile and compressive stresses. A VB data processing system is developed for convenient data processing, and a FEM is used to validate the method of the measurement of 3-Demensional residual stress by releasing the macro-residual stress.(2)Secondly, A three-dimensional elastic-plastic finite element milling model is developed by simplifying the actual Milling state. The process of cutting force is acted through dynamic loading, unloading on the unit cell surface for the removed material, and the removed material is realized through FEM "Live and death cell technology". The reasons of plastic deformation and the residual stress are explained by the theory, and the model is validated by the process of typical thin-walled parts. (3) With the established cutting model, different allowances of side wall for finish, as well as conditions of different clips and the same clips with the different card position are simulated for the deformation influence of thin-walled components.(4) Finally, the simulation study is made for the overall deformation on the box machining sequence of aeronautic thin-walled components with multi-box.This paper is full of great realistic meaning and value for reducing or inhibiting components'effective deformation, and the prediction of NC machining deformation for the overall structure components of the aeronautic product.