Optimization Design Of Mechanical Pendulum Structure Of Differential Capacity Seismometer

Earthquake is a kind of sudden natural disaster which seriously endangers people's lives and national economic safety.When earthquake occurs,strong ground vibration and associated ground cracks make all kinds of buildings collapse and damage,equipment and facilities damage.In order to reduce the loss caused by earthquake disaster,it is necessary to collect and analyze the seismic information.Seismometers can collect a large amount of seismic information in real time and play an important role in earthquake prediction and post disaster monitoring.Different types of seismometers can record earthquakes with different distances and intensities.Differential capacitance seismometer is a kind of seismometer with high resolution and wide frequency band.Its development direction is to have a wider frequency band.For the differential capacitance seismometer,the lower the natural frequency of the mechanical pendulum,the better the low frequency response of the seismometer.However,the traditional parameter optimization method can not effectively reduce the natural frequency of the mechanical pendulum,so it is an effective way to obtain high-performance differential capacitance seismometer by reducing the natural frequency of the mechanical pendulum through topology optimization to obtain better low-frequency response.By studying the working principle and structure of the differential capacitance seismometer,it is found that the natural frequency of the mechanical pendulum of the differential capacitance seismometer is the key factor affecting the low frequency response of the seismometer.In order to reduce the natural frequency,the topology optimization design of the mechanical pendulum of the differential capacitance seismometer is carried out.Solid Works is used to draw the components of the mechanical pendulum of the differential capacity seismometer,and the assembly is completed in the software according to the real installation relationship.The completed three-dimensional model is imported into ANSYS Workbench for finite element modeling.In ANSYS Workbench,the static structure of the mechanical pendulum is analyzed,and the displacement and stress nephogram are obtained.The natural frequency before optimization is obtained by modal analysis.According to the analysis results,the topology optimization design scheme is worked out.With the objective of reducing the natural frequency of the mechanical pendulum of the differential capacity seismometer,the topology optimization of the mechanical pendulum of the differential capacity seismometer is carried out by using the topology optimization module of ANSYS Workbench,and the structure of the mechanical pendulum with a new cross spring is obtained,Through the static structure analysis,modal analysis and simulation,its performance is analyzed.The performance of the optimized differential capacitance seismometer is tested,and the self noise of the seismometer is measured.The sine calibration method is used to test the natural frequency of the mechanical pendulum before and after optimization.The experimental results show that the natural frequency of the actual mechanical pendulum is reduced by 17%,from 5.3 Hz to 4.4 Hz,which proves the feasibility of the optimization design.