Effect of axial force-to-moment ratio on initial rotational stiffness of double-node system

• Published in: Engineering structures 2024-03, Vol.303, p.117454, Article 117454
• Main Authors: Wang, Ruhao, Liu, Qing, Ge, Hui-Bin, Zhao, Yang
• Format: Article
• Language: English
• Subjects: Axial force-to-moment ratio; Component method; Double-node system; Initial rotational stiffness; Rectangular hollow section; Spatial structure
• ISSN: 0141-0296
• DOI: 10.1016/j.engstruct.2024.117454

Double-node system is a typical end-face connector for spatial structures. It is found that the initial rotational stiffness of this connection is affected by the axial force of the member. This study aims to investigate the effect of the axial force-to-moment ratio λ on the initial rotational stiffness K0 of the double-node system. An analytical model composed of springs and a rigid plane is proposed according to the force transmission mechanism. The K0-λ curve first exhibits linear, then inverse proportional, and finally linear again, corresponding to the three mechanical states. Next, the component stiffnesses are illustrated by parametric studies, which are related to the geometrical parameters of the connection. And the component stiffnesses are used to derive the constant coefficients of the overall stiffness in the K0-λ formula through the component method. Finally, the process of determining the initial rotational stiffness is described, followed by some examples. Comparisons show that the proposed formulae are consistent with the numerical results, which are effective for predicting the initial rotational stiffness of the double-node system under different axial force-to-moment ratios. •An analytical model of the double-node system is proposed.•The relationship between the initial rotational stiffness K0 and the axial force-to-moment ratio λ is investigated.•An energy-based method for determining the rotation of connection is proposed.•The formulae for component stiffnesses and overall stiffnesses are developed.