Abstract:
The test and the updated lumped mass finite element model were used to predict the response of the valve installed in the pipeline under the seismic excitation of different frequency components, and the hazard of high frequency seismic excitation to large-mass nuclear safety class valves in the pipeline was studied. The results show that the high frequency seismic excitation causes the nuclear safety class valve to resonate with its own mode of vibration. At this moment, the top of the valve replaces the position where the valve is connected to the pipe to become the position with the largest response amplitude in the valve, which causes the drive mechanism installed on the top of the valve to suffer severe seismic conditions. Increasing the pipe damping and valve stiffness can effectively reduce the hazard of high frequency excitation to the valves, but increasing the valve stiffness will lead to the increase of the pipe response amplitude. When the equivalent static method is used for seismic identification of the valve, the analysis result is insufficient to estimate the internal force of the horizontal part of the valve body, and has a large margin to estimate the internal force of the vertical part of the valve body, the valve cover and other upper parts of the valve.