ABSTRACT
A parametric study of the ultimate strength of multiplanar KK-joints in circular hollow sections is presented. The study was carried out using a well calibrated and validated finite element (FE) model and the joints were subjected to anti-symmetrical axial loading. In all, forty joints were analysed to investigate the effect of the various geometric parameters on static strength. For those joints that failed by chord bending, the probable cracking locations were found to be in accord with experimental evidence from previous research. The FE data, together with existing test and numerical data, form a database of which multiple regression analysis was carried out. Two sets of strength equations were developed from the regression analyses: one provides correction functions which can be applied to an existing planar K-joint equation and the other relates the non-dimensional strength directly to the geometric parameters. Both sets of equation were found to provide strength predictions to a very high degree of accuracy.
