Simulation And Experiment Study On Subsurface Crack Of Zirconia Ceramic Grinding Under Dynamic Impact Strain Rate Effect

With excellent physical and chemical properties,zirconia ceramics have been widely used in medical,military,aerospace and other fields.At present,precision grinding is the main processing method for zirconia ceramic materials.Due to the high brittleness and hardness of the material,it is easy to produce surface/subsurface damage such as cracks and residual stress during processing,which greatly reduces the mechanical properties and service life of the ceramic workpiece.Therefore,the research on material removal behavior and crack propagation mechanism of engineering ceramics in precision grinding process is of great significance in improving surface quality and machining efficiency.This research regard adjacent abrasive cutting and grinding wheel grinding on zirconia ceramics,considering the strain rate effect,the surface/subsurface damage of zirconia ceramics under dynamic impact loading is analyzed and discussed through theoretical analysis,finite element simulation and processing experiment,and the strain rate effect on the grinding process of zirconia ceramics is explored.Thus,the surface quality of zirconia ceramics in grinding process can be optimized.Below is the specific research work:(1)Based on the Johnson-Holmquist-Ceramic constitutive model,the finite element model of adjacent abrasive particles impacting on zirconia ceramics was established.The impact process between abrasive particles and workpiece was studied,including the propagation of impact stress wave,the damage layer,the stress distribution and the strain rate of the material.(2)The double abrasive cutting experimental platform were established.The interference experiment of adjacent abrasive cutting was carried out on zirconia ceramics.The influence of strain rate effect under impact was considered,and the cutting force,surface morphology of scratches after cutting and subsurface damage were analyzed.Combined the results of simulation and adjacent abrasive cutting experiment,the influence of strain rate effect and stress wave superposition effect caused by dynamic impact was revealed for the material removal mechanism of zirconia ceramics.(3)Grinding experiment of zirconia ceramics was carried out,and the influence of strain rate effect on zirconia ceramics grinding was discussed.The grinding force,surface morphology and subsurface damage were analyzed.Combined the results of simulation and adjacent abrasive cutting experiment,the influence of strain rate effect caused by dynamic impact was further revealed for the material removal mechanism in the grinding of zirconia ceramic.