Prediction method for discrete pre-tightening force of bolt rotation angle method

Abstract

The invention discloses a prediction method for discrete pre-tightening force of a rotation angle method, and the prediction method is mainly used for design and assembling processes of main bolts of engines. The method is divided into two conditions of: in an elastic range, carrying out force balance on a bolt connection pair by utilizing a generalized Hooke's law: a combined computation of <Sigma> F=0 and deformation compatibility <Theta>=(<Delta>Lpull+<Delta>Lpush)*360 / P, so as to obtain pre-tightening force distribution of the rotation angle method; and if plastic deformation occurs to the bolt connection pair, adopting a law of conservation of energy: obtaining a false stress greater than real stress and a false strain less than the real strain under elastic assumption, obtaining a real stress and a real strain by adopting the law of conservation of energy, and finally obtaining the pre-tightening force distribution of the rotation angle method through nonlinear iterative computations of force balance and deformation compatibility. The method disclosed by the invention has the advantages of being simple in computation and well-organized.

Description

technical field [0001] The invention relates to a bolt tightening process, which is used in the design and assembly process of automobile parts. Background technique [0002] Auto parts are often bolted, especially in engine assembly. The main bolts of the engine include cylinder block and cylinder head connecting bolts, connecting rod bolts, crankshaft main bearing seat bolts, crankshaft front end center bolts, and flywheel bolts. During the design and simulation analysis of related parts, it is necessary to simulate the assembly load, and the bolt pretightening force is the main assembly load of the related parts. The bolt pretightening force seriously affects the deformation of the related parts during assembly and the working performance Therefore, the bolt connection becomes the most important boundary condition in the design and simulation of related parts, and it is also one of the main factors that affect the assembly quality in the manufacturing process and need to ...

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Problems solved by technology

However, there is no literature or special edition on how to express the pretightening force dispersion of the corner method in engineering. At present, there is no literature or special edition in this regard. Europe and the United States often use the pretightening force increased by 5% to 10% on the basis of the yield point method to obtain bolts. The maximum pretightening force, this method can be applied to the angle method above the yield point, but the specific bolt tightening process cannot be obtained, and the tightening process needs to be obtained after the sample is made. At the same time, for the elastic range The law of corners is unpredictable

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