Dynamic modeling method for suspended liquid filling tank

Abstract

The present invention discloses a dynamic modeling method for a suspended liquid filling tank, and belongs to the field of spacecraft dynamics modeling and analysis. The ''shell + beam + concentrated mass point elements'' dynamic modeling method for the suspended liquid filling tank is adopted, a tank section connected with the support boundary is simulated by using the shell element, and other tank section is simulated by using the beam element; and in addition, in order to ensure a relatively large stiffness after pressurization of the actual tank, the multi-point constraint RBE2 is established on the upper and lower end surfaces of the shell element, and according to the method of consistency of the center of mass, the liquid is attached to the beam element in a corresponding position by using the discrete concentrated mass element. Compared with the traditional ''beam element'' and ''shell element'', the method disclosed by the present invention combines the advantages of different elements, so that on one hand, the connection stiffness between the tank and the main structure is not changed, both local modalities and feature point peak response are taken into account at the same time, and the consistency of the obtained modal and dynamic response predictive value and experimental value is better.

Description

[0001] Technical field: [0002] The invention relates to a dynamic modeling method of a suspended liquid-filled storage tank, which belongs to the field of spacecraft dynamics modeling analysis. [0003] Background technique: [0004] For spacecraft large-size / non-supported liquid-filled tanks, the liquid-filled tanks are generally connected to the main structure support through their own lugs or end frames, and the mass of propellant often accounts for 40% or more of the take-off mass, so , The liquid-filled storage tank has a greater impact on the overall and local modalities of the spacecraft assembly, sometimes up to 50% to 60%; at the same time, due to the limitation of the installation method, there may be a possibility between the branch of the liquid-filled tank and the main structure There is a certain offset or cantilever, which makes the vibration environment of the liquid-filled storage tank and the connected liquid pipes relatively harsh. In engineering, the finite ele...

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Problems solved by technology

[0009] The second method uses shell element modeling, which is more accurate in simulating the stiffness of the tank connection. However, due to the influence of the breathing mode of the tank shell model, the normalized vibration mode values ​​of the front and rear bottom of the tank are quite different from the test values, and the generalized Mass calculation is high

That is to say, using the above two methods will make the estimated value of the POGO stability analysis margin better than the actual flight state, which may put the flight in a dangerous state

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