Design And Simulation Of Reed-accelerometer In The Liquid Helium Environment

In the development of superconducting gravity gradiometer,a number of cryogenic vibrator are required to measure the cross coupling coefficient and the common-mode rejection ratio.The vibrators are rigorously required to work only at one degree of freedom,so that one can distinguish the concerning effect from the others.To evaluate the performance of the vibrators,cryogenic accelerometers need to be developed ahead.This thesis focuses on the structural design of the cryogenic horizontal accelerometers.Based on a comparative analysis,the metal suspending beam is chosen to construct the accelerometer for the compatibility with cryogenic application.Using ANSYS,the oscillator parameters have been optimized,including the number of beams,the geometric parameters of beam and test mass,and the joint position of the beam.It is concluded that the double-beam structure shows better performance the single-beam one.Its first order mode is a pure horizontal translation along the sensitive axis.When the oscillator's natural frequency is set to be 5.5Hz,The stiffness ratio of the second mode to the first mode reach 316.8.Furthermore,extensive exploration has been carried out to seek higher stiffness ratio.Resultantly,a novel notched beam structure is obtained.With these beams,the stiffness ratio of the oscillator soars to 3816.This finding provides a new strategy to build low cross-talking accelerometer.Inevitably,various errors exist in the fabrication of the accelerometer,which will deteriorate the performance.Thus,a systemic simulation has been done.The influences of the dominant fabrication error have been clarified,and the error tolerances have been given at the given resolution.These results will act as fabrication guides to guarantee the accelerometer's performance.