Iterative global-local methods to consider the local deformation effects in the analysis of thin-walled beams

University of Technology Sydney. Faculty of Engineering and Information Technology.Thin walled members are one of the most widely used structural elements in modern structures. Beam-type finite elements, which are conventionally used to model these members, cannot capture cross-sectional deformation. On the other hand, the use of two-dimensional shell-type elements leads to computationally uneconomical models that cannot be adopted for common engineering practice. The aim of this study is to develop a numerical method to incorporate the effect of local deformation on the global response of a thin-walled beam. For this purpose, the Iterative Global-local Method is developed in which beam elements are used as the global model while two-dimensional shell elements are placed at critical regions to constitute the local model. The two models are synchronised within each computational iteration via a kinematically appropriate mathematical link. The Iterative Global-local Method is developed for elastic and elasto-plastic material response, for fibre-reinforced composite laminates, for pipes and curved thin-walled members. The accuracy and efficiency verification of the method is verified through comparisons with detailed finite element modelling and test data from the literature

Multi-scale overlapping domain decomposition to consider local effects in the analysis of pipes

Elevated pipelines are commonly encountered in petro-chemical and industrial applications. Within these applications, pipelines normally span hundreds of meters and are thus analysed using beam-type onedimensional finite elements when the global behaviour of the pipeline is sought at a reasonably low computational cost. Standard beam-type elements, while computationally economic, are based on the assumption of rigid cross-section. Thus, they are unable to capture the effects of cross-sectional localized deformations. Such effects can be captured through shell-type finite element models. For long pipelines, shell models become prohibitively expensive. Within this context, the present study formulates an efficient numerical modelling technique which effectively combines the efficiency of beam-type solutions while retaining the accuracy of shell-type solutions. An appealing feature of the model is that it is able to split the global analysis based on simple beam-type elements from the local analysis based on shell-type elements. This is achieved through a domain-decomposition procedure within the framework of the bridging multi-scale method of analysis. Solutions based on the present model are compared to those based on full shell-type analysis. The comparison demonstrates the accuracy and efficiency of the proposed method

Multi-scale overlapping domain decomposition to consider local effects in the analysis of pipes

Elevated pipelines are commonly encountered in petro-chemical and industrial applications. Within these applications, pipelines normally span hundreds of meters and are thus analysed using beam-type onedimensional finite elements when the global behaviour of the pipeline is sought at a reasonably low computational cost. Standard beam-type elements, while computationally economic, are based on the assumption of rigid cross-section. Thus, they are unable to capture the effects of cross-sectional localized deformations. Such effects can be captured through shell-type finite element models. For long pipelines, shell models become prohibitively expensive. Within this context, the present study formulates an efficient numerical modelling technique which effectively combines the efficiency of beam-type solutions while retaining the accuracy of shell-type solutions. An appealing feature of the model is that it is able to split the global analysis based on simple beam-type elements from the local analysis based on shell-type elements. This is achieved through a domain-decomposition procedure within the framework of the bridging multi-scale method of analysis. Solutions based on the present model are compared to those based on full shell-type analysis. The comparison demonstrates the accuracy and efficiency of the proposed method

Shear-deformable hybrid finite-element formulation for lateral-torsional buckling analysis of composite thin-walled members

A shear deformable hybrid finite element formulation is developed for the lateral-torsional buckling analysis of fiber-reinforced composite thin-walled members with open cross-section. The method is developed by using the Hellinger-Reissner functional. Comparison to the displacement-based formulations the current hybrid formulation has the advantage of incorporating the shear deformation effects easily by using the strain energy of the shear stress field without modifying the basic kinematic assumptions of the thin-walled beam theory. Numerical results are validated through comparisons with results based on other formulations presented in the literature. Examples illustrate the effects of shear deformations and stacking sequence of the composite layers in predicting bucking loads.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author