46 research outputs found
Numerical modelling of CHS joints with multiplaner double-K configuration
No full textA numerical study on the static strength of CHS (circular hollow section) joints with the multiplanar double-K configuration is presented. The aim of the work was to establish a valid and accurate finite element model for an extensive parametric study and to investigate the various factors which influence static strength. These factors included modelling the effect of the weld geometry, boundary conditions at chord and brace ends, mode of loading, chord length and material properties. The numerical results were rigorously calibrated against existing experimental data. The study has given an insight into the many aspects of elastic-plastic finite element analysis which is gradually replacing experimental testing as the main tool of research in tubular joint technology.<br/
Strength of multiplanar tubular KK-joint under anti-symmetrical loading
No full textA parametric study is presented of the ultimate strength of multiplanar KK-joints in circular hollow sections, which are commonly found in both onshore and offshore structures. The study was carried out using a well-calibrated and validated finite-element model, and the joints were subjected to antisymmetrical axial loading. In all, 40 joints were analyzed to investigate the effect of the various geometric parameters on static strength. Those joints that failed by chord bending can be divided into two groups: one with cracking occurring in the transverse gap region and the other with cracking occurring in the longitudinal gap region. This finding is in accord with experimental evidence from previous research. The finite-element data and the existing test and numerical data form a database on which multiple regression analysis was carried out. Two sets of strength equations were developed from the regression analysis: one provides correction functions that can be applied to an existing planar K-joint equation and the other relates the nondimensional strength directly to the geometric parameters. Both sets of equations were found to provide strength predictions to a very high degree of accuracy
Strength of multiplanar tubular KK-joints under anti-symmetrical axial loading
No full textA parametric study is presented of the ultimate strength of multiplanar KK-joints in circular hollow sections, which are commonly found in both onshore and offshore structures. The study was carried out using a well-calibrated and validated finite-element model, and the joints were subjected to antisymmetrical axial loading. In all, 40 joints were analyzed to investigate the effect of the various geometric parameters on static strength. Those joints that failed by chord bending can be divided into two groups: one with cracking occurring in the transverse gap region and the other with cracking occurring in the longitudinal gap region. This finding is in accord with experimental evidence from previous research. The finite-element data and the existing test and numerical data form a database on which multiple regression analysis was carried out. Two sets of strength equations were developed from the regression analysis: one provides correction functions that can be applied to an existing planar K-joint equation and the other relates the nondimensional strength directly to the geometric parameters. Both sets of equations were found to provide strength predictions to a very high degree of accuracy
A parametric study of strength of tubular multiplanar KK-joints
No full textA parametric study of the static strength of circular hollow-section joints with the multiplanar KK configuration, commonly found in both onshore and offshore structures, is presented. The study, carried out using a well-calibrated and validated finite-element model, investigated the effects of the various geometric parameters on static strength. Particular attention was given to joints with low γ ratios, to where the amount of experimental data is scarce, to the effect of γ on strength, and to the influence of the two major failure modes. In all, a total of 50 joints were analyzed. The study has established a clear demarcation boundary between the two failure types as a function of the transverse gap between the braces. A strength database—compiled from the finite-element data generated and 37 existing test results—was used to formulate strength equations through multiple regression analyses. The equations were found to provide strength predictions to a very high degree of accuracy
Ultimate capacity of axially loaded multiplaner double k-Joints in circular hollow sections
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A new ultimate capacity formula for unstiffened CHS T, TT and K-joints under axial brace loads
No full textIn order to make simple design equations for CHS joints, a new ultimate capacity formula for K-joints under axial loads is derived by a multiple regression analysis method and using the database of Makino et al. (1996). Although there are several failure modes in K-joints, an ultimate capacity formula for joints failing only by local deformation of the chord wall is derived in this study. The derived ultimate capacity formula can be used for K-joints, Tjoints, and TT-joints failing with no radial deformation of the chord wall between the braces. This formula represents the first stage of a continuous formula for hub joints where the braces are positioned around the chord circumference (e.g. T-, TT, X-, XT-, and XXjoints), and gap joints (i.e. joints with longitudinally spaced braces). The accuracy of the new ultimate capacity formula is slightly lower than the individual joint equations of Kurobane et al. (1984) and Paul et al. (1994), but it is simpler than the existing formulae.<br/
Static strength of multiplanar KK-joints- a reassessment of the database and estimation equations
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