High-precision calculating method of random vibration dynamic stress of mechanical structure

A technology of mechanical structure and dynamic stress, applied in computing, special data processing applications, instruments, etc., can solve problems such as loss of accuracy, large error, and low computing efficiency

Inactive Publication Date: 2015-08-19
NORTHWESTERN POLYTECHNICAL UNIV
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Problems solved by technology

[0008] In order to solve the problems of low calculation efficiency and large error in the existing calculation method of random vibration dynamic stress of mechanical structure, the present invention proposes a high-precision calculation method of random vibration dynamic stress of mechanical structure, on the basis of converting random excitation into deterministic excitation , using the modal stress coefficient calculation to avoid the loss of accuracy when calculating the stress from the displacement derivative; and performing static correction to consider the influence of higher-order modes that are ignored during modal interception

Method used

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  • High-precision calculating method of random vibration dynamic stress of mechanical structure
  • High-precision calculating method of random vibration dynamic stress of mechanical structure
  • High-precision calculating method of random vibration dynamic stress of mechanical structure

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Embodiment Construction

[0030] Describe the present invention according to specific embodiment below:

[0031] Firstly, the derivation process of this method is given:

[0032] Motion equations of multi-degree-of-freedom discrete structures subjected to random excitation

[0033] [ M ] { y · · } + [ C ] { y · } + [ K ] { y } = { f ( t ) } - - - ( 1 )

[0034] In the formula:

[0035] [M]——Structural mass matrix;

[0036] [C]——structural damping matrix;

[0037] [K]——structural stiffness matrix;

[0038] {y}——discrete structure acceleration vector, velocity v...

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Abstract

The invention discloses a high-precision calculating method of a random vibration dynamic stress of a mechanical structure. The random excitation is converted into certainty excitation, and calculation efficiency is improved when mode-coupling effect is completely taken into consideration. By the mode stress coefficient calculation, precision reduction during stress calculation by displacement derivation is avoided; static force is corrected, neglected influence of high-order modes in mode interception is considered, and calculation accuracy of random dynamic stress is improved. Cross-correlation terms among all vibration-involved modes are included during calculation, and exact solution is obtained. For large-scale and complex projects, the high-precision calculating method is easy to operate and implement and is higher in calculation efficiency than a conventional algorithm. In addition, calculation accuracy is improved by introducing a stress mode matrix and static force correction terms of the high-order modes.

Description

technical field [0001] The invention relates to the technical field of structural mechanics analysis, in particular to a high-precision calculation method for random vibration dynamic stress of a mechanical structure. Background technique [0002] When the structure is subjected to random vibration loads, especially when the load frequency covers the multi-order natural frequencies of the structure, the structure will be at a high level of dynamic stress, so that fatigue damage will occur. Therefore, dynamic stress is the original data required for structure dynamic strength check and vibration fatigue life estimation. Only with accurate dynamic stress response can the structural fatigue life be predicted more accurately, which is directly related to the safety and reliability of the structural system. [0003] The structural forced vibration equation describes the dynamics of the system under excitation. It is a time-domain description of the structural dynamics behavior a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
Inventor 谢慈航薛璞吴媛谭邵毅虞泽亮陈欢欢李玉龙
Owner NORTHWESTERN POLYTECHNICAL UNIV
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