Method for calculating inherent frequency of bolting structure under normal and tangential load coupling effect

Abstract

The invention provides a method for calculating the inherent frequency of a bolting structure under the coupling action of normal and tangential loads, and the method comprises the steps: S1, calculating the maximum contact area of all micro-convex bodies according to the normal load borne by the bolting structure, and obtaining the normal contact rigidity, tangential contact rigidity and static friction force of a single micro-convex body under contact deformation; s2, calculating the normal contact rigidity, tangential contact rigidity and static friction force of the bolting structure and the actual contact area of the bolting structure; s3, enabling a contact interface of the bolting structure to be equivalent to a virtual thin layer, and calculating attribute parameters of the virtual thin layer under the combined action of the normal load and the tangential load; and S4, establishing a contact surface equivalent finite element model based on the virtual thin layer attribute parameters, performing modal analysis to obtain the inherent frequency of each order of the bolting structure with the rough contact interface under the coupling action of different normal loads and tangential loads, and accurately calculating the inherent frequency of the bolting structure under the coupling action of the normal loads and the tangential loads.

Description

technical field [0001] The invention relates to the technical field of natural frequency calculation, in particular to a calculation method of the natural frequency of a bolted structure under the coupling action of normal and tangential loads. Background technique [0002] Bolted connection is a widely used way of connecting parts in mechanical equipment. The engineering surface has rough fractal characteristics on the microscopic scale. Under the combined action of normal and tangential loads, the natural frequency of the bolted structure with rough contact interface presents nonlinear characteristics. . Considering the rough topography of the contact interface, it is beneficial to accurately calculate the natural frequencies of each order of the bolted structure under different external loads, which is conducive to predicting the dynamic behavior of the mechanical structure system and reducing engineering accidents caused by resonance. [0003] In the research on the dyn...

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Problems solved by technology

[0004] At present, there are two main methods to obtain the natural frequency of the bolted structure under different external loads: the first is a theoretical calculation method combining analysis and numerical values, using the fixed joint of the spring-damper equivalent bolted structure. Although this method Simple and practical, but ignoring the coupling relationship between viscoelastic units and the coordinates of viscoelastic units, it is impossible to calculate the natural frequency under the joint action of normal and tangential loads, and this modeling method is not easy to be compared with Existing FE software integration

The second is a calculation method that relies on the experimental test results. Through the combination of experiments and finite elements, the relevant parameters of the virtual thin layer are obtained, and then substituted into the finite element model to obtain the natural frequencies of each order of the bolted structure. The disadvantage of this method is that The calculation accuracy depends on the experimental results of the bolted structure in the early stage, and the influence of the roughness between the contact interfaces of the bolted structure is also ignored, so that there is a large error in the obtained natural frequency of each order of the bolted structure compared with the actual one.

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