Design And Simulation Study Of Γ-type Cantilever Piezoelectric Accelerometer

Medium and high-frequency vibration monitoring is of great significance to ensure the safety of engineering structures.These vibrations include high-frequency shock vibrations and noise caused by polygonal wear of high-speed EMU wheel treads,which seriously affect the safety of railway operation and riding comfort.In response to the need for medium and high-frequency vibration monitoring,this thesis proposes a design scheme for high-performance Γ-type cantilever piezoelectric acceleration sensors.The feasibility and reliability of this design were analyzed and verified through theoretical analysis,finite element simulation,and simulation application testing.The main contributions of this work are as follows:(1)Introduction.Based on the investigation of the existing methods for middle and high-frequency vibration monitoring,and the research and application of piezoelectric acceleration sensors,the design scheme and technical route for highperformance piezoelectric acceleration sensors with Γ-type cantilever were introduced.(2)Design and theoretical analysis of the Γ cantilever piezoelectric acceleration sensor.The characteristics and performance of different piezoelectric materials were compared and analyzed.high-performance piezoelectric material is used as piezoelectric elements.To address the deficiencies of existing cantilever piezoelectric acceleration sensors in middle and high-frequency vibration monitoring,the structure optimization scheme for a Γ-cantilever piezoelectric acceleration sensor was proposed,and the preliminary structure parameters were determined.A dynamics model of the piezoelectric acceleration sensor with a Γ cantilever beam was established,and the calculation formulas of surface stress,natural frequency,and sensitivity of the cantilever beam were derived,which provide a theoretical basis for the subsequent finite element simulation analysis of sensor performance.(3)Parameter optimization and performance analysis of the Γ cantilever piezoelectric acceleration sensor.COMSOL finite element simulation and theoretical analysis were used to analyze the stress distribution of the Γ cantilever beam with or without fillet structure.The Γ cantilever piezoelectric acceleration sensor was then simplified into a mass-spring-damping single-degree-of-freedom system to determine the natural frequency and damping ratio.On this basis,the effects of different structural parameters on the natural frequency and sensitivity of the sensor were simulated to determine the optimal structural parameters,and its linearity and transverse sensitivity indexes are analyzed,and finally the performance of common piezoelectric acceleration sensors is compared.(4)Simulation test of the Γ cantilever piezoelectric acceleration sensor.A coupling model of the bogie axle box and the Γ cantilever piezoelectric acceleration sensor for the CH380 B high-speed EMU and high-speed EMU UM simulation kinetic model were established to analyze the vibration response signals of the axle box under different types of wheel polygon excitation.The dynamic sensing characteristics of theΓ cantilever piezoelectric acceleration sensor under corresponding working conditions were obtained.The feasibility of the designed sensor was finally verified by simulation tests.