Parametric study on performance of circular tubular K-joints at elevated temperature

• Finite element model for analyzing tubular K-joints at elevated temperature is presented.
• Effect of some parameters on temperature development of K-joints is analyzed.
• Effect of some parameters on critical temperature and critical time of K-joints is studied.
• Influence sensitivity of some parameters is analyzed and discussed.

An indirect sequentially coupled thermal-stress analysis model is proposed for studying the performance of Circular Hollow Section (CHS) tubular K-joints at elevated temperature. The accuracy and the reliability of the presented model are verified by comparing finite element results with reported experimental measurements. Deforming rate criterion, not conventional deformation limit, is presented to determine the critical temperature of a tubular K-joint in a heating process. Afterwards, a preliminary parametric study is conducted to study the effect of some parameters on the temperature development and the critical temperature of K-joints. These parameters include convection coefficient, emissivity, loading ratio, geometrical parameters (include brace-to-chord diameter ratio β, chord radius-to-thickness ratio γ, and the intersecting angle between the brace and the chord θ), and initial chord stresses. The results indicate that convection coefficients and emissivity have no effect on the critical temperature of a K-joint but have great effect on critical time. The critical temperature of a K-joint is slightly enhanced with the increase of β and θ. However, with the increase of γ, the critical temperature decreases slightly. The results also indicate that the critical temperature of a K-joint decreases rapidly with the increase of braced loading ratio and initial chord stresses.