Mechanical Analysis Of A Novel And Multi-link Mechanical Press Mechanism

Forging technology has the characteristics of higher efficiency,better quality and lower cost,which plays an important role in industrial production.Multi-link mechanical press is an important forging and pressing equipment.Compared with the ordinary crank-slider mechanism,multi-link mechanical press has lower working speed in the plastic deformation zone of the workpieces,which can prevent cracking,reduce vibration and noise,and improve the service life.Due to these reasons,the multi-link mechanical press is widely applied to electrical,hardware,automobile,transportation,military industries and other fields.Regarding a novel multi-link mechanical press as the research object in the paper,kinematics,dynamic statics,rigid-body dynamics and elastic dynamics of the press were systematically studied.The main contents are as follows:Firstly,kinematics modeling for multi-link mechanical press was worked out.The structural features of six-link mechanical press mechanism were studied.In terms of complex vector method,the kinematic model of the mechanism was established,and the kinematic solution of the slider was derived.Numerical calculation and virtual prototype simulation analysis of kinematics were carried out by Matlab and Adams software,through which the correctness of the kinematics model was verified.Taking the maximum speed and velocity fluctuation of slider during the working stroke as design objective,the optimization model of the mechanism was obtained,and dimension optimization based on genetic algorithm was presented.Secondly,kinetostatics model of the multi-link mechanical press was established.According to the components’ force analysis,by use of D’Alembert principle,the kinetostatics model of the press mechanism was carried out.The Matlab was applied to calculate the model of the press and the Adams was used for virtual prototype simulation analysis.The constraint forces of motion pairs and the balance torque of the crank under the state of no-load and load were obtained.By comparing numerical results with simulation analysis,the correctness of the kinetostatics model was verified.Then,rigid-body dynamics model for the multi-link mechanical press was built.Choosing crank’s angular displacement as the generalized coordinate,the kinetic energy equation,potential energy equation and the generalized force were listed.And then,rigid-body dynamics model was established by use of Lagrange equation.Using Matlab software to calculate dynamics model and applying Adams software to simulate this press mechanism,the driving torque of the crank in the case of no-load and load were acquired.The correctness of rigid-body dynamic model was verified by comparing the results of numerical calculation and simulation analysis.Finally,elastic dynamics model of the multi-link mechanical press was presented.Finite element method was employed to divide the flexible links into beam units.The generalized coordinates of unit were set.Based on the Lagrange equation,the elastic dynamics model of the element was acquired.Taking system’s constraints into account,the system elastic dynamics equation was gotten by assembling each unit elastic dynamic equations.After solving system elastic dynamics equation by Newmark method,Matlab was used to do the numerical calculation,acquiring curve graphs referred to the kinematics error,deformations of elastic-links and natural frequency of the system.