Simulation Design of Oil-Filled High-Pressure Sensor Based on Graphene

The output result of the pressure sensor is difficult to be stable in a large pressure range. The traditional pressure sensor adopts the membrane structure, which will produce strong nonlinearity under the action of large pressure, and require complex transformation to convert the measured data into linear results. In this paper, based on the piezoresistive effect of graphene, a high-pressure sensor was designed through the cylindrical sensitive structure, which could realize the linear output of the pressure value within the pressure range of 400 MPa. The sensor structure was mainly composed of an elastic metal diaphragm, a compressible silicone oil, a cylinder structure and a graphene sensitive membrane. The sensor structure was optimized by theoretical and simulation analysis, and the metal diaphragm size structure which only produces elastic strain in the 400 MPa pressure range was obtained by analyzing the diaphragm thickness. Then the fluid-solid coupling method was used to simulate the deformation of the whole structure of the sensor, and the relationship between the cylinder structure size and the strain of the outer wall, the natural frequency of the whole structure was determined. The reasonable location of the graphene sensitive membrane was obtained by finding the maximum strain location. Finally, the linear relationship between the strain on the outer wall of the cylinder structure and the pressure measured by the sensor was investigated. The results show that the designed sensor structure can work within the pressure range of 400 MPa, and the appropriate size of the sensor cylinder structure is 1. 2 mm in length and 0. 08 mm in thickness. At this size, the natural frequency of the sensor is 127 kHz, and the maximum strain on the outer wall of the cylinder structure can reach 2 082 με. The sensitivity can reach 5. 205 με/MPa when the graphene sensitive membrane is installed at the highest strain point. In the range of 0 to 400 MPa, the linearity of the sensor structure is good, and the relative error of structure linearity is only 0. 37%.