Dynamic Characteristics And Design Of Vibration Suppression Device In Deep-hole Drilling Process Based On Magnetorheological Fluids

The vibration suppression of the cutting tool system in deep-hole drilling is warmly needed due to the increasing demand on high efficiency,high precision and high reliability for metallurgical industry,nuclear power and ordnance industry.However,considering the complexity and the diversity of machining conditions,how to find an effective approach for suppressing tool's vibration has become a key issue so as to guarantee the hole quality in practical drilling progress.Based on the structure and vibration characteristics of tools system in deep-hole drilling,a novel structural layout of the vibration suppression device is proposed.The structure optimization of the magnetorheological vibration suppression device and its specific structure parameters are given,with the goal of acquiring a desired vibration suppression device's damping force output and the magnetic saturation inner strength of magnetic induction,to reach the magnetic saturation of the controller.Utilizing the finite element method,the magnetic field distribution of the new vibration suppression device and its damping characteristics output are analyzed.And according to the dynamic excitation testing on the cutting tool system of deep-hole drilling,the association between stiffness and damping characteristics of the cutting system of the depth drill and the dynamic response time of the system are obtained under the different vibration frequency or excitation current.Thus,the correctness and the feasibility of the designed parameters of the new suppression device can be verified.Considering the nonlinear dynamic characteristics of the magnetorheological fluids,the constitutive models of the vibration suppression device based on the Bingham-Logistic model,the polynomial model and the Bouc-Wen model are developed respectively.By utilizing the theory of nonlinear least squares method to identify the model parameters,the recognition accuracy and the adaptability of the dynamic characteristics of the new suppression device are discussed in three different mechanical models.Finally,the vibration control experiments of the tool system in deep-hole drilling is carried out in order to investigate the relevant experimental results of tool vibration control under the conditions of different excitation currents and cutting parameters,and simultaneously,it is can be seen from the experimental results that the new model of magnetorheological damping configuration proposed in this thesis can satisfy the demand of deep hole drilling process effectively.