Analyzing method of dynamic failure loads of rivet connecting area

Abstract

The invention provides an analyzing method of dynamic failure loads of a rivet connecting area. The analyzing method comprises the following steps: by designing a dog bone sample, a stress-strain curve of a metal material under quasi static and dynamic loads is measured and converted into an effective stress-strain curve; a Johnson-Cook constitutive model comprehensively considering the strain strengthening effect, the strain rate effect and the temperature effect is given; a detailed finite element model of the rivet connecting area is built to obtain the connecting piece dynamic pull-out failure load of the rivet connecting area f<P_t> dot (varepsilon) and the extrusion failure load f<P_br>dot(varepsilon); the dynamic limit failure stress of a rivet material is given, and the dynamic limit tensile load f<S_t>dot(varepsilon) and the dynamic limit shearing load f<S_s>dot(varepsilon) of a rivet are obtained; and through f<P_t>bullet(varepsilon), f<P_br>bullet(varepsilon), f<S_t>bullet(varepsilon), f<S_s>bullet(varepsilon) and the rivet reduction coefficient K1, the dynamic tensile invalid load and the dynamic shearing invalid load of the rivet connecting area are obtained finally. According to the analyzing method, the research and development time can be shortened greatly, the research and development cost can be greatly reduced, the analyzing precision and reliability degree are ensured, and the analyzing method has wide practical engineering application prospects.

Description

technical field [0001] The invention relates to the field of impact dynamics analysis, in particular to a method for defining the dynamic failure load of a rivet connection area. Background technique [0002] Rivets are a form of fasteners, the main function is to provide structural continuity and transfer the load between the connecting parts. Due to stress concentration and other reasons, the connecting part is usually the weak link of the structure, and the damage mode of the connecting part mainly considers the rivet Tensile failure, rivet shear failure, connector pull-off failure, and connector extrusion failure are four main failure modes. The traditional static theory ignores the inertial effect of the micro-element of the medium, while the dynamic impact load is often measured in milliseconds or even microseconds, the inertial effect and flow effect of the micro-element must be considered, which also leads to the fact that the rivet and its connection area are subjec...

AI Technical Summary

Problems solved by technology

The traditional static theory ignores the inertial effect of the micro-elements of the medium, and the dynamic impact load is often measured in milliseconds or even microseconds, and the inertial effect and flow effect of the micro-elements must be considered, which also leads to the fact that the rivet and its connection area are subjected to static loads. When it shows different mechanical properties than when it is subjected to impact load

For the failure mode and failure load of the rivet itself and the rivet connection under impact load, it can only be obtained through the rivet dynamic test at present. Due to the variety of rivets, the complex load action form and the large loading speed range, the rivet dynamic failure test will cost a lot of time and money

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