Mechanical Properties of a Novel Modular Joint of Single-Layer Aluminium Alloy Lattice Shell

To overcome the disadvantages of the discontinuous webs in the joint area of aluminium-alloy gusset joints and to further improve the efficiency of high-altitude positioning and installation of aluminium-alloy reticulated shell joints, this paper proposed a novel modular joint. Four sets of joint specimens were processed by computerized numerical control machine tools to carry out bearing capacity tests. The mechanical characteristics, failure mechanism and stiffness trends of this novel joint were explored. The results show that the proposed novel modular joints are significantly better than the traditional gusset joints in terms of bearing capacity and ductility. The flexural strength of the novel joints is 17% higher than that of the traditional gusset joints, and the novel joints have good deformability, which can prevent brittle failure. The results of elastoplastic finite element optimization analysis based on multiple contacts show that the theoretical failure mode and the curve of the load versus displacement of the joints are in good agreement with the actual measurements. Although the bearing capacity of the joints increases with increasing thickness of the modular unit and the reinforcement ring, when the thickness of the bottom plate exceeds twice the thickness of the top plate, this increase is very limited. Based on the working mechanism of the novel joints, a simplified calculation formula for their ultimate bearing capacity is proposed, which provides a theoretical basis for the engineering design and specification preparation of this type of joint henceforth.