This paper describes a parametric study of K-connections between square hollow sections based on 20-noded solid elements and includes (partially) overlapped connections and connections made of members of equal width. The FE generator is described, as well as the method by which the results were incorporated into a set of parametric formulae which describe the relation between the geometry of the connection and the stress concentration at a certain position on the connection for a given load case.
After earlier studies by the authors on the fatigue behaviour of T- and X-connections (van Wingerde, 1992), further work has been carried out regarding the fatigue behaviour of K-connections. Earlier studies were either based on simpler models with shell elements, often omitting the weld shape and rounded comers (Soh and Soh, 1992), or these studies omitted more complex geometries, such as (partially) overlapped connections or connections of which chord and branch members have an equal width (Panjeh Shahi, 1994; Herion, 1994). The main reason why this has only been done now is that the modelling tools available are often inadequate for large numbers of complex Finite Element (FE) models. The first aim of the study is the establishment of parametric equations, which describe the relationship between the geometry of the connection and the so-called Stress Concentration Factor (SCF), which in turn describes the ratio between the hot spot stress (van Wingerde et al., 1995) and the nominal stress as determined from linear beam theory. In order to allow for superposition of load cases, stresses are considered only in certain locations. Each location considered in the connection and each (independent) load case requires one equation. Together with Srh.s.-Nf lines and thickness correction factors this will provide the designer with a complete method for the fatigue design of K-connections between square hollow sections.
