Design And Properties Study On High Temperature Compression Mode Piezoelectric Accelerometer

HT(High Temperature)piezoelectric accelerometer,function as vibration testing,fault diagnosis,is widely used in occasions including aerospace industry,military manufacturing,power industry,shipbuilding etc.The temperature of core devices in these fields could reach about 1000? even higher when they are working.Therefore,it is vital to develop a kind of piezoelectric accelerometer,which can meet the requirements of high working temperature.Currently domestic piezoelectric accelerometer can work at the maximum temperature of 550? according to some documents,which is just a prototype in the laboratory.The highest working temperature of domestic commercial products can be at 480?,and that of foreign products can be at 770?.Most of the accelerometers requiring high temperature are used in military projects,which means the related documents are in state of confidentiality.The trading of accelerometer products was banned by some countries.Therefore,it is necessary to conduct researches on HT piezoelectric accelerometers independently.This paper analyzed the piezoelectric accelerometers from four aspects,including research methods on design,mathematical modeling,finite element analysis,and HT experiment.First,existing design methods on mechanical structure were summarized and some useful methods in HT piezoelectric accelerometers were concluded.The main point was the design and calculations on preload and natural frequencySecond,dynamic models on HT piezoelectric accelerometers were established and simplified,which contain 6,and 8 degrees of freedom respectively.Based on the model,how thickness and material property of parts affect the natural frequency of whole structure was analyzed.It was proved that the upper parts have a different effect on natural frequency from lower ones.This phenomenon provides some inspirations on structure optimization of accelerometers.Then contact stiffness was introduced to the model with 6 degrees of freedom,which makes result more precise.With data about elasticity modulus of materials in different temperature,how temperature affect natural frequency of HT sensor system was also analyzed.Third,a 3D model of accelerometer was built and ANSYS Workbench was used to make modal analysis at the structure.In modal progress,reasonable computing element and mesh were confirmed for calculation.Based on result of modal,its harmonic response under different temperature was analyzed.Furtherly,the sensitivity performance was calculated.Meanwhile,a thermal conduction behavior of nude and encapsulation structure was simulated.Suggestions on improvements in heat insulation and cooling were provided.Finally,an experiment to test temperature performance of YCOB crystals was designed.Then a prototype of piezoelectric accelerometer was designed and manufactured.With an experimental platform set up,the sensitivity was tested within high temperature of 800?.It shows the average sensitivity of two cutting-type sensors rise as the temperature rise.The cutting-shape optimization can be an effective way to improve sensitivity.