Axial force–bending moment interaction in a jointing system: Part II: Analytical study

• An analytical technique was proposed for including the interaction between the compressive axial force and bending moment.
• In this technique, the hardening behaviour of the connection is simulated by a proposed mathematical model.
• The softening behaviour is estimated from the limit surface of the axial force and bending moment diagrams.
• The effects of compressive axial force-bending moment interaction on the behaviour of a toggle frame were investigated.
• It was found that, significant effects of axial force occur after the limit point.

In this paper, a suitable technique, based on experimental results, for including the interaction between the compressive axial force and bending moment in the space structure jointing system is proposed. In this technique, the hardening behaviour of the connection is simulated by a mathematical model and the softening behaviour is estimated from the limit surface of the axial force and bending moment diagrams. The interaction between the axial force and bending moment was taken into account in the finite element code. Also, effects of compressive axial force–bending moment interaction on the load–displacement behaviour of a toggle frame are studied. It was found that, although the compressive force increases the connection stiffness initially, it has no significant effect on the behaviour of the toggle. Also, significant change occurs after the limit point. This indicates that the released kinetic energy after post-buckling behaviour increases, that is, the axial force causes the release of more kinetic energy after post-buckling and consequently sudden failure of the structure.