Structural performance of a novel combined nested bolted joint for aluminum alloy mega-latticed structures

Abstract

A novel steel-aluminum joint system is first presented for aluminum alloy mega-latticed structures. This joint can be effectively applied to the connection of large-diameter tube members with complex spatial locations in space structures. The joint's finite element model is examined and validated, followed by a case study of one joint, including static analysis and an analysis of the bending moment-rotation curve. According to the moment-rotation curve, the joint is classified as a type of semi-rigid joint. Furthermore, the analysis considers key parameters that impact the joint's bending, axial, and torsional performance, such as the number of bolts per ring, the rings of bolts, and the thickness of the joint zone. Two simplified formulas for joint stiffness are proposed to evaluate the overall structural stability. Finally, a stability analysis of an aluminum alloy mega-latticed structure is conducted, incorporating this joint and the proposed simplified formulas. The ultimate load of the mega-latticed structure with the joints is found to be about 0.7 of that with ideal rigid joints with the same parameters. This paper presents a potential solution for appropriate connections in large-span aluminum alloy mega-lattice structures, thereby serving as a reference for the design of the joints in related space structures.