Study On A Method To Identify The Dynamic Parameters Of Machine Joint Surface

With the processing level of advanced manufacturing industry tends to improve,each industry has higher requirement to the dynamic performance of mechanical equipment.Mechanical joints are the inherent structures for mechanical equipment,the dynamic characteristics of Mechanical joints have a significant impact for the mechanical equipment.With machine tools as an example,about sixty percent up to eighty percent of the total stiffness and ninety percent of the total damping originated from the joint surface of the machine tools.In the dynamic design of mechanical structure, the key to establish accurate dynamic model of the mechanical structure is able to get the right kinetic parameters of the joint surface.Therefore,dynamics modeling and parameter identification of the joint surface is always a worthwhile research topic.Based on this key issue,This paper conducted the following research:First,make a brief summary of the current research work on the mechanical properties of the joint surface.On the basis,I design a test model of the the cantilever beam which containing a fixed joint surface.Then,in this paper,the method of "Combination of Theoretical Modeling and Modal Experimental" is adopted to identify the dynamic parameters of the joint surface.According to the cantilever beam structure to establish its dynamic model.Then, using DASP mode test system for modal test specimens to get the natural frequency and damping ratio of the cantilever structure.Finally,through the characteristic equation of the system to calculate the stiffness and damping coefficients and make optimizations.And then.analyzes the stiffness and damping coefficients of the cantilever beam model how them are changing under different binding conditions.Through three different sizes of the cantilever beam and under different pre-tightening torque to get the stiffness coefficient and damping coefficient of the joint surfaces and analysis of the influence of the characteristic parameters.At last, by using the ANSYS software to build finite element model of the beam which considering the affect of joints and not considering the affect of joints and making modal analysis.Then,base on the results of experimental modal analysis to compare the finite element analysis results by the method of comparing similar modal shape’s frequency.The result proved that the identification method is effective.