The Finite Element Modeling And Dynamics Analysis Of Pneumatic Wheel Finishing Tools

The technology of pneumatic wheel finishing improved the efficiency and quality in die and mold finishing.The pneumatic wheel finishing technology,basing on six degrees of freedom,significantly removed the surface marks to get die surface of high quality.In this paper,modal analysis was applied to a deep study on the structure property of pneumatic wheel finishing tools.The equivalent dynamic parameters of joint parts in pneumatic wheel finishing tools were determined and the finite element modeling was built firstly.Then we conducted the modal analysis on the finite element model using ANSYS,with a hampering method as testing.The principle axis dynamic modeling of the pneumatic wheel finishing was built afterwards,simplified basing on rules of theory.After a modal analysis,the matching mechanical modeling was finally achieved,with which we calculated the critical speed of rotation.The stiffening effect of stress,spinning softening effects and effects of principle axis under the combined influence between them were analyzed to gain empirical formulas of approximate calculation for the dynamic frequency.The contents and main results are as follows:(1)We used equivalent stiffness and damping to simulate the joint parts of pneumatic wheel finishing tools,built the infinite elements modeling in ANSYS,and figure out the Equivalent stiffness and equivalent damping parameters of Pneumatic Wheel Finishing Tools bolt joints,build finite element model of Pneumatic Wheel Finishing Tools by it,and then the free modal and the constrained modal of Pneumatic Wheel Finishing Tools were studied.(2)A modal testing system was designed for pneumatic wheel finishing tools.The hampering methods were employed to gain modal frequency and damping ratio of pneumatic wheel finishing tools in each order,compared with the results of infinite elements and tested the accuracy of the model.(3)Building the three-dimensional entity model basing on the feature size of the principle axis of pneumatic wheel finishing tools,we got the matching dynamic model through a simplification to the model.We also got the critical speed of rotation at each order with the formulas of critical speed of rotation.(4)We studied the stiffening effect of stress,spinning softening effects and effects of principle axis under the combined influence between them,showing that stiffening effect of stress has a larger influence on the dynamic frequency than spinning softening effects.And rotors of the principle axis at each order would become larger with the increasing rotation speed,when the two factors existed.We finally derived the empirical formulas for calculating the dynamic frequency.