engleski

Numerical Modelling of Structures Consisting of Shell and Beam Elements

The analysis of the structures consisting of shells and columns implies specific problems of connecting various finite elements into a compatible entire. All available algorithms applied to the analysis to shell structures are based upon finite shell elements with five degrees of freedom per node, which represents an obstacle in connecting them with finite elements of the beam. This thesis develops a comprehensive and efficient algorithm for numerical modeling of structures consisting of shells and columns (beam elements). The main problem related to the incompatibility of displacement, i.e. more precisely rotation in the nodes, which is common to finite shell and beam elements, has been solved by introducing the finite rotational stiffness of the shell around the normal to its middle surface. Hence, an isoparametric shell element was formed with six degrees of freedom per node, which apart from satisfying the compatibility conditions in joints of structural elements, also proved suitable for modeling folded shell structures. Another important unit in the development of the numerical model is the implementation of a numerical interpretation of the beam element into the basic model for the analysis of shell structures. According to past experience regarding various formulations of the rotational degree of freedom around the normal to the mid-surface of the shell, this work suggests an authentic solution.

numerical modelling ; shell ; beam ; finite elements ; structures

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