Identification Of Zirconia Ceramic Material Characteristic Parameters And Research On Grinding Process

Zirconia ceramics are widely used in mechanical manufacturing,automobile,shipbuilding,aerospace and military equipment and other fields because of their high strength,high temperature resistance and strong impact resistance.It has practical engineering significance for the research of material properties.At present,experimental and numerical calculation are the two main methods to study the properties of materials.The mechanical responses of materials under different working conditions can be obtained by experimental method,and the parameters that are difficult to be obtained by experimental method can be obtained by numerical calculation.In the process of numerical calculation,the acquisition of material characteristic parameters has a great influence on the accuracy and accuracy of the results.These characteristic parameters are usually obtained by fitting a large number of test data,and the whole process is time-consuming and laborious.Therefore,the computational inverse method of material parameter identification based on partial test is developing day by day.In this paper,zirconia ceramics as the research object,starting from the mechanical properties of the material test,the mechanical response of the material obtained from the test,using a computational inverse method to obtain the material constitutive model characteristic parameters.Based on the obtained material model parameters,the model is applied to the grinding simulation of zirconia ceramics,and the corresponding grinding experiments are carried out to verify the reliability of the simulation model.The relationship between grinding process parameters and grinding processing is investigated,and multi-objective optimization of grinding parameters is carried out.The specific research contents are as follows:(1)The static and dynamic mechanical responses of zirconia ceramics are obtained by using electronic testing machine and split Hopkinson pressure bar(SHPB)in order to provide input data and verification data for the inverse calculation of model parameters of zirconia ceramics.The morphology of zirconia ceramics after dynamic impact is observed by super depth of field microscope,and the influence of different strain rate impact on the failure morphology of samples is investigated.(2)Based on the obtained dynamic response of zirconia ceramics,the Johnson-Holmquist Ⅱ(JH-2)constitutive model parameters of zirconia ceramics are identified by computational inverse method.Corresponding to SHPB impact test,SHPB finite element numerical model is established,and the parameters of strong sensitivity model are identified by optimization algorithm.Based on the identified model parameters,the impact simulation results show that the model parameters obtained by inverse calculation method have high accuracy and good applicability under multi-strain rates.(3)A simulation model of zirconia ceramic grinding is established by using the identified material characteristic parameters,and corresponding grinding tests are carried out to verify the accuracy of the model.The variation of stress and strain in grinding simulation process is analyzed,and the influence of different machining parameters on grinding force is discussed.The grinding process includes three stages: grinding,scratching and cutting.In a certain range,the grinding force has a negative correlation with the wheel speed,and a positive correlation with the work piece feed speed and grinding depth.The damage caused by grinding can be reduced and the grinding quality can be improved by increasing the grinding wheel speed and decreasing the work piece feed speed and grinding depth.(4)Based on numerical calculation,a second-order response surface approximation model is constructed to reduce the simulation calculation time.Multi-objective optimization is carried out for the machining parameters by using NSGA-Ⅱ multi-objective optimization algorithm,which is verified by grinding test.The results show that the grinding efficiency is improved after optimization.The surface roughness and surface morphology of the work piece are compared before and after optimization,and the work piece after optimization has smaller surface roughness and more regular surface morphology.