Investigating Static and Dynamic Behavior of the Strain Gauge Type Pressure Sensor in Exposure to Thermal Stresses

Due to the extreme importance of pressure measurement in various industrial applications, studying different types of failures possible in a pressure sensor seems to be very necessary. The presented research analyses thermally affected faults in a strain gauge type pressure sensor. The studied electro-mechanical sensor is composed of a thick plate and a very thin membrane in direct contact with the fluid whose pressure is being measured. The membrane is connected to the sensing plate via the incompressible interface fluid (silicone oil). The temperature difference between the membrane and the body of the sensor creates thermal stresses in the membrane. The equations governing the motion of the sensing plate and membrane in the presence of temperature differences have been presented and solved simultaneously. The occurrence of the buckling phenomenon is studied for the first and second deformation modes of the membrane. It has been shown that in the second deformation mode of the membrane, the existing coupling between the membrane and the plate vanishes which leads to the decrement of the equivalent stiffness of the structure. Therefore, the probability of the occurrence of the buckling phenomenon in the membrane increases significantly compared to the first deformation mode. The effect of geometrical parameters of the sensor on the measurable pressure range of the sensor is investigated in detail. The transient response of the sensor subjected to the dynamic pressure force is studied. The effect of nonlinear terms on the frequency response of the sensor has also been examined.