Study On The Prediction Model Of Drilling Temperature Field Of Cortical Bone And The Design Of Virtual Instrument

The friction between the surgical twist drill bit and the workpiece in the cortical bone drilling process will generate a large amount of drilling heat.Since the drilling environment is not conducive to the dissipation of heat and the heat transfer coefficient of the bone tissue is relatively low,the heat accumulation in the bone tissue near the drill bit is more serious and the local temperature will be very high.At present,the temperature measurement method can not accurately obtain the temperature of the drilling zone.If we can establish the temperature prediction model of cortical bone during drilling from the perspective of theoretical mechanism,we can accurately analyze the temperature field distribution of bone.Based on the theories of metal cutting and heat transfer,a three-dimensional mathematical model of temperature distribution in drilling cortical bone was established.The thermocouple temperature acquisition module was designed by LabVIEW,and the corresponding functions were enriched.The main contents of this paper are as follows:The causes of heat generation during drilling and the ways of transmission were analyzed.A three-dimensional heat conduction differential equation of cortical bone drilling was established based on the object and characteristics of this research,and the corresponding single value conditions were listed according to the actual situation of drilling process.The heat conduction method was used to solve the heat conduction differential equation of cortical bone,and the prediction of the temperature distribution of cortical bone was obtained.In the process of solution,the temperature distribution was first derived from the stationary point heat source,then the temperature distribution wass obtained by the moving point heat source.Finally,combined with the real drilling heat source,we got the solution of the temperature distribution of the cortical bone during drilling.The chip AD595 and YAV data acquisition card were used to establish the measurement module of drilling temperature based on LabVIEW,and the thermocouple calibration module was also designed.In order to enrich the measurement and control function of LabVIEW,the test information input module and information inquiry module were developed by connecting with the database.The accuracy of the mathematical model of cortical bone drilling temperature was verified by cortical bone drilling test.The virtual instrument cortical bone drilling temperature prediction module was developed by using the hybrid programming technology of LabVIEW and MATLAB.The influence of of different depths and radial on temperature distribution of cortical bone and different velocity on thermal necrosis of cortical bone were analyzed.