Damping Parameter Test And Performance Study Of Machine Tool Sandwich Structure

The dynamic characteristic is an important factor which affecting the precision of machine tools,and the material combination is an effective method to improve the dynamic characteristio.At present,the constraining damping sandwich structure has been widely used in the fields of automobile,electronic products,machine tools and other fields.In order to study the damping characteristics of the sandwich structure used in machine tools,the bolted sandwich structures with HT200 and QT500 materials as the base and constraint layers,NBR plate,PP plate,concrete plate and paraffin plate as the sandwich materials were made.This paper studies the modeling methods of the sandwich structures and the influence of the parameters such as base material,constraint layer material,sandwich material and thickness,pre-tightening moment on the damping ratio of sandwich structures.First,consider the production of sandwich structure which the sandwich material are concrete and Concrete and paraffin board:with HT200 sandwich structure as an example,the topology optimization technique based on OptiStruct 13.0,in order to improve the structure of the first order natural frequency as the optimization goal,and make the specimen quality to reduce by 15%,the first order natural frequency increased by 4%,and the preload of sandwich structure is calculated.Second,taking HT200 sandwich structure with 20mm base and constraint layer and 2mm thick damping the NBR layer as an example,the static model of the damping layer and the dynamic model of the sandwich structure were studied.The gasket element was used to model and analyze the damping layer material,and the stress distribution range and the displacement change process were obtained.The first ten natural frequency of the structure were extracted by modal analysis.Based on this,the transient response of the structure was analyzed,and the resonance frequency of the structure was obtained to be 2623Hz.Again,analyzes the contact model of bolt connection structure containing concrete structure,using ABAQUS software binding constraint model is established,based on the theory of contact model and spring damping element model,the results show that the binding constraint model,and the whole stiffness of the structure,error is bigger,The precision of spring damping element modal is difficult to grasp,has much to do with bolt number and distribution,and the contact model is the most close to the actual situation of the model.Finally,the TST5912 dynamic signal testing and analysis system is used to conduct the hammering experiment on the plywood structure,and analyze the modal mode and damping ratio of the structure when the boundary condition is free.The experimental results show that:the thinner the base material is,the greater the damping ratio change rate of sandwich structure is,and the damping ratio of rubber sandwich structure is greater than that of plastic sandwich structure.When the inter layer material is concrete and paraffin,the concrete material is more conducive to improving the overall damping ratio of the structure.