Research On Deformation Of Aircraft Structural Parts Based On Adaptive Clamping Force

With the continuous improvement of the design ideas in national aviation industry,aluminum alloy aircraft structural parts have been more and more widely used in a variety of aircraft structures.However,the aircraft structural parts have poor rigidity,thin wall and difficult controlling in processing deformation.Thus the aircraft structural parts usually failed to meet the requirements,such as processing accuracy and surface quality.Over these years,the problems restrict the development of national aviation industry.At present,"smart manufacturing" has become a promising development direction for the aviation manufacturing industry.Moreover,its key is the design of intelligent fixtures.Thereby,it is significant to control and predict the deformation of aircraft structural parts under the intelligent fixture environment.As a result,finite element numerical simulation is applied to doing in-depth research about the problem.Firstly,using 7050-T7451 as the aviation aluminum alloy material,then analyzing the key theories,such as material constitutive relation,chip and workpiece separation criterion and finite element mesh model,are to construct the finite element model of 3D milling machining simulation.Based on this model,the numerical values of milling force and its variation law,both of which are validated by the cutting simulation software Advant Edge,stress and strain distribution are obtained in the processing area.Secondly,the adaptive clamping force of intelligent fixture is studied by using hierarchical optimization design method.In the method,the fixture layout and clamping force are synchronously optimized by combining the finite element method and the genetic algorithm with the objective function of both minimizing machining deformation and averaging workpiece deformation.Then,a simplified method,quasi-dynamic analysis,is proposed to study the adaptive clamping force.Based on the proposed method,the above optimization and the adaptive clamping force optimization design model,a set of adaptive clamping force curves on the machining path is obtained.It is evaluated by an actual case.Finally,the workpiece deformation is predicted by separately using the constant and adaptive clamping forces based on the simulation process.The results show that the adaptive clamping force plays an effective role in controlling the deformation.