Mechanical behaviour of a novel steel dovetail joint subjected to axial compression loading

Abstract

In this study, two types of novel steel dovetail joints for single-layer grid shells are proposed and investigated. The design concept, design method, and FE modelling method are discussed. Experimental and numerical analysis methods are adopted to explore the performance of the new joint system under axial compression loads. Moreover, a parametric analysis is conducted to evaluate the impact of design parameters including the hub diameter, hub ring thickness, hub height, hub slot edge thickness, and beam-throat slope angle on the joint behaviour. Based on the experimental and numerical results, both types of joints exhibit the same performance under compression loading, with three main failure modes: beam-throat failure, hub failure, and combined beam-throat and hub failure. Beam-throat failure occurs when the compressive bearing capacity of the hub is greater than that of the beam neck. The hub failure mode occurs when the compressive bearing capacity of the beam is higher than that of the hub, and the combined failure mode occurs when the compressive bearing capacities of the hub and beam-throat are similar. Finally, equations for calculating the yield and ultimate bearing capacities of the examined joints and hubs are proposed and calculated. By comparing the numerical, theoretical, and corresponding experimental results, it is shown that the derived equations can be used to calculate the mechanical performance of the joints in this study.