Method for calculating modal shape recognition factors and additional mass of a flexible shell and application of the method

Abstract

The invention discloses a method for calculating modal shape recognition factors and additional mass of a flexible shell under fluid immersion and application of the method. The method comprises the steps: giving model parameters and measuring point distribution; superposing sine waves to generate simulation data: simulating the motion condition of each measuring point during actual vibration by superposition of sine waves with different frequencies and amplitudes, thus to obtain the simulation data of the acceleration of the measuring point; separating the superposed sine waves through Fourier transform; obtaining amplitudes and directions of accelerations at different measuring points under different dominant frequencies of the amplitude-frequency function after Fourier transform; obtaining the component of the acceleration on the modal shape through the dot product of the acceleration amplitude vector obtained in the fourth step and the shape vector at the measuring point; solving a dynamic pressure modal shape recognition factor; and solving the additional mass through the acceleration and the dynamic pressure vibration mode identification factor. The data processing method provided by the invention can directly process the original data of the test, is wide in application, and can be used for various cylindrical shell identification modes and different mode proportions.

Description

technical field [0001] The invention relates to a calculation method, in particular to a method for calculating the mode shape identification factor and additional mass of a flexible housing under fluid immersion, and belongs to the field of nuclear power energy technology control. Background technique [0002] There are many cylindrical cylindrical equipment in the reactor body, such as the core body, support cylinder, heat exchanger, etc., which are all cylinders of different sizes. These structures generally have the characteristics of large size and thin wall, so they are less rigid. Moreover, these cylinders are immersed in the fluid medium, and the fluid-solid coupling between the cylinder and the fluid medium will change the natural vibration characteristics of the structure during vibration. Therefore, the seismic analysis and verification of the reactor is the focus of the reactor safety evaluation. When calculating the fluid-solid coupling effect, the method of ad...

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Problems solved by technology

Although some software or methods can identify the mode shape of the measured cylinder, they cannot give the proportion of different mode shapes when different mode shapes are superimposed under transient excitation

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