Stress concentration factors for multi-planar DKT tubular truss joints under axially balanced loads

Abstract

This paper presents a set of empirical equations to predict stress concentration factors (SCFs) in multiplanar right-angle DKT-joints. The SCFs were obtained from linear elastic finite element analyses, wherein the weld profiles were carefully modelled. The modelling techniques were first verified against previous experiments on steel and acrylic test specimens and were found to yield accurate predictions. Parametric studies encompassing a total of 54 DKT-joint models, including two different loading conditions, were performed. The SCFs from 8 locations around the perimeters of the middle and outer braces on the chord side were extracted from the models. The carry-over effect in the unloaded braces was carefully included in the investigation. The resulting SCF database was used to derive empirical parametric equations for the SCFs in DKT-joints using non-linear regression analysis.