Numerical Analysis Of Cracked Rivet Joint

Rivet joint is a kind of mechanical joint being widely used in engineering structure.Along with the aging of the structures, fatigue crack will appear near the location of the rivetsdue to the stress concentration at the joint, which may result in catastrophic consequence. Afinite element model, based on the plate/shell element, is proposed in this paper to analyze thecracked rivet joint structures and calculate the stress intensity factor under stretching load toidentify the main factors which may affect its rupture strength.Rivet joint structure is generally asymmetry or dissymmetry in geometry, thus bendingdeformation exists under stretching load. However, bending effect is usually ignored in thecurrently available analytical and numerical models in order to simplify the analysis as a 2-Dproblem. In this paper, a 4-node plate element combined with rivet element and contactelement is employed to analyze two typical rivet joint structures, i.e., lap joint and butt joint.The penetration between two sub-plates in the lap zone or butt zone is avoided by introducingcontact element into the proposed finite element (FE) model. Bending deformation and itseffect on in-plane displacement of the two typical rivet joint structures are studied by usingthe proposed FE model. Virtue crack closure technique (VCCT) is employed to calculateenergy release rate and stress intensity factor of the cracked rivet joints.Based on the analysis of the two typical rivet joint structures and the contrast of platemodel and plane model, some meaningful conclusions are obtained.1. The adjustment of total length and thickness of subplate or change the boundary conditionwill affect the maximum deformation of the structure under stretching load, however iteffct on stress intensity factor can be ignored.2. The trend of stress intensity factor gained by plate model is similar to that of plane model,however the maximum value of which are quite different, the former is much bigger thanthe latter, so it is dangerous to analyze such structure with obvious bending effect byusing plane model.