Structural Design And Characteristics Research On A Pressure Sensor With Pre-stressed Clamped Beams

Pressure sensors are the most common micro mechanical sensors,which are widely applied in aviation,mechanical,shipbuilding,bridge construction.As the typical high precision pressure sensor,resonant pressure sensors measure the pressure by utilizing the frequency change caused by oscillator deformation.The measurement theory promotes the stability and responsibility of resonant sensor.A new pressure sensor based on pre-stress effects is proposed to improve the sensibility of resonant pressure sensor.The characteristic of pre-stress and vibration of the sensor is analyzed and determining the method of changing the stiffness of resonator by pre-stress to increase the sensitivity.Finally experiments proved that the pressure sensitivity is improved by 3.2 times.The technical scheme in this paper is as follows:1.A double ended triple beam resonator with magnets based on the analyzing of pre-stress effect of the beam is proposed.According to the Euler-Bernoulli beam deformation theory and the vibration principle of the multi-degree-of-freedom system,the vibration characteristics and vibration modes of the resonator are obtained.By imposing the concentrated prestressed loads on the beam,the expression of natural frequencies of the resonator under pre-stress is analyzed in combination with bending deformation and statically indeterminate theory.The relationship between the natural frequency and the pressure sensitivity increases with the application of the pre-stress by imposing the pressure.2.Optimizing the structure dimension of designed sensor and establishing the relationship between pre-stress and pressure sensitivity.The correlations between length,thickness,and the ratio of the coupling part with resonant frequency are analyzed by finite element software and the structure dimension of the resonator is optimized.The study of the method and scope of application of pre-stress has demonstrated the effectiveness of longitudinal pre-stress in sensitivity increase and determined the effective pre-stress range in the pressure scope.It is demonstrated that the sensitivity of the fundamental frequency is increasing within a certain range of pre-stress,which shows a clear improvement comparing with no prestressed structures.3.Setting up the experimental platform for vibration test and prestressed pressure test to verify the improvement of pre-stress on the sensitivity of pressure detection.The prestressed pressure sensing structure is produced according to the theory analysis and the detection system of vibration characteristics and pressure sensing is set up.The vibration characteristics of the resonant pressure sensor are experimentally studied,and the pressure detection sensitivity of the prestressed structure and the non-prestressed structure is compared and verified.Results show that the nature frequency of the resonator with prestressed structure increased,and the sensitivity is 4.2 times of non-prestressed structure.In this paper,a new method of improving the sensitivity by pre-stress is proposed from the perspective of structure by combination of theoretical analysis,simulation and experimental verification.A pressure sensor with prestressed resonant beam is designed to provide insights for the study of the effect of pre-stress on vibration characteristics.