Complicated multi-body system vibration mode modeling method based on energy method
A multi-body system and modeling method technology, applied in the field of vibration modeling of complex multi-body systems based on the energy method, can solve problems that cannot represent the magnitude of vibration energy, cannot fully reflect the vibration intensity, and have different dimensions
Inactive Publication Date: 2016-12-07
NO 719 RES INST CHINA SHIPBUILDING IND
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Problems solved by technology
[0003] 1) The moment of inertia in each rotation direction is usually not equal, so the numerical value of the corresponding element of the rotation degree of freedom in the natural mode shape cannot represent the vibration energy in this direction;
[0004] 2) The mode shape components corresponding to the translation degree of freedom and the mode shape components corresponding to the rotation degree of freedom have different dimensions, and the values are not comparable;
[0005] 3) The displacement ratio between different rigid bodies does not consider the mass of the rigid body to which it belongs, and cannot fully reflect the vibration intensity on this degree of freedom
Method used
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[0053] This embodiment uses a model composed of three rigid bodies, such as figure 1 Shown. Among them, the rigid body 1 is connected to the foundation through four elastic elements a, and the rigid body 2 and the rigid body 3 are both connected to the rigid body 1 through four elastic elements b. Establish a Cartesian coordinate system at the center of mass of each rigid body. Related quality parameters and stiffness parameters are shown in Table 1 and Table 2.
[0054] Table 1 Mass and moment of inertia of rigid body
[0055]
[0056] Table 2 Rigidity of elastic element
[0057]
k(N / m)
k(N / m)
k(N / m)
Elastic element a
800000
5000000
1500000
Elastic element b
1500000
4000000
2000000
[0058] The calculated system mode shapes and energy-based system modes are shown in Table 3 and Table 4, respectively.
[0059] Table 3 Vibration shape of the original system
[0060] Frequency (Hz)
16.29
35.11
44.40
12.50
46.71
43.80
64.01
27.32
10.61
25.56
107.6
45.48
52.79
7.41
18.73
20.29
99.87
51.58
X1
-0...
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The invention discloses a complicated multi-body system vibration mode modeling method based on an energy method. The complicated multi-body system vibration mode modeling method comprises the following steps: aiming at a complicated multi-body system composed of n rigid bodies, establishing a mathematical model, wherein the rigid bodies are connected through an elastic element; connecting at least one rigid body onto a rigid body foundation; and aiming at a mathematical vibration mode of the complicated multi-body system, carrying out quality factor weighting, wherein a quality factor is a square root, corresponding to rigid body degree-of-freedom mass, of each element, so as to obtain an energized vibration mode of the complicated multi-body system. The energized vibration mode can definitely characterize a ratio relation of vibration energized displacement between degrees of freedom of each rigid body when the system is naturally vibrated at certain order, and provides important supports for the design of the complicated multi-body system.
Description
Technical field [0001] The invention belongs to the field of equipment vibration reduction device design, and specifically relates to a method for modeling a mode shape of a complex multi-body system based on an energy method. Background technique [0002] For the vibration of a complex multi-body system, it is necessary to carry out the natural mode analysis of the system during the vibration design and test and check, and consider the six-degree-of-freedom spatial motion of each rigid body. Through the analysis of the mode shape, we can know: ①The vibration intensity of the system at a certain order of natural frequency; ②Whether the excitation direction of the disturbance source can be avoided when the disturbance frequency cannot be avoided. However, when analyzing the natural mode shapes obtained through mathematical calculations, there are still the following three problems: [0003] 1) The moment of inertia in each direction of rotation is usually not equal, so the numerica...
Claims
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IPC IPC(8): G06F17/50
CPCG06F30/17
Inventor 商超李强余永丰陶襄樊朱海雄强磊
Owner NO 719 RES INST CHINA SHIPBUILDING IND