The effect on deflection of steel diaphragm of pressure sensor due to change in boundary condition in the welded region

Abstract

Manufacturing a high-pressure sensitive diaphragm type sensor is a complex task. Due to it’s complex shape, several parts are designed individually. It involves welding of several parts. As welding involves several parameters it’s difficult to control the welding geometry where it is being fused. So it is likely that the physical boundary condition of the welded region will be different from the theoretical boundary conditions. So the change in boundary condition will make the deflection of the diaphragm different. For a precision device, any effect of a change in boundary condition can affect the deflection of the diaphragm largely. Thus, any effect of imperfect welding in a high precision measuring device can hamper the sensitivity of the particular device. A welded diaphragm of steel for a pressure sensor using eddy current sensor to detect it’s deflection due to pressure can lose it’s effectivity, due to the unpredictable boundary conditions created after the welding. In this paper, we will be trying to find the cause of deviation between the theoretical and experimental results due to the effect of a change in boundary conditions at the welded region.