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|Title:||Local effects in rectangular hollow section joints|
|Authors:||Ostrowski, Kazimierz Piotr|
|Department:||Civil Engineering and Engineering Mechanics|
|Keywords:||civil engineering and engineering mechanics;Civil Engineering;Civil Engineering|
|Abstract:||<p>A theoretical and experimental study of RHS joints is presented, with particular attention being devoted to RHS gap K joints due to their popularity and complex behaviour. The theoretical aspects include the derivation of a nine-node general shell element with six degrees of freedom per node, capable of modelling multiple intersections between plates and shells. The material behaviour is described using the Von Mises yield criterion and the Prandtl-Reuss flow equations. The plasticity algorithm allows a sampling point to yield within a load increment and traces both the elastic and inelastic stress increments accordingly. Refined numerical analyses allow for an accurate tracing of the yield surface in every iteration. Each sampling point within an element is capable of carrying individually specified material properties. This makes it possible to account for a strain-hardened zone near the corners of an RHS or for the material properties of the weldment. The experimental investigation included 26 isolated RHS joints which were subconfigurations of a gap K joint. The testing program made it feasible to assess the effects of the angle of branch inclination and the flexibility of the base. Numerous strain gauges and rosettes mounted on the branch walls near the weldment, provided load-strain characteristics at the toe, the heel and the sidewall for the entire history of loading. The effectiveness of the heel area and the type of failure mode were found to depend strongly on the angle of branch inclination. The rigid or flexible base conditions affected the stress distribution in the branch walls and the direction of the principal axes. The developed finite element model was used in the numerical simulation of the behaviour of RHS joints. All the joint configurations tested were subjects of the numerical simulation in three independent stages which allowed for the model to be thoroughly verified. A very good agreement between the experimental and numerical results was achieved in all stages. The numerical analysis provided complementary results towards better understanding of the behaviour of tested joints. The same numerical model was utilized in a parametric study of a gap K joint which included the effects of : the angle of branch inclination, the width ratio, the gap size and the chord width to thickness ratio. The results are presented by means of stresses in the branch member walls and the local deflections of the chord connecting face. A number of new observations are made which result in recommendations for the design of RHS joints.</p>|
|Appears in Collections:||Open Access Dissertations and Theses|
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