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A New Cable-Pulley Algorithm in RFEM

Abstract

The cable-pulley system is widely used for its advantages. In this paper, application of a new algorithm for the calculation of cables on pulleys is presented. Unlike other algorithms, this algorithm enables to take the magnitude of the radius of each pulley into account. This new algorithm is implemented in the RFEM program because of its higher accuracy and efficiency. Comparison of the commonly used algorithm, which ignores pulley radius, and the new algorithm is presented.

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PARAMETRIC STUDY OF THE STRUCTURAL RESPONSE OF NPP CONTAINMENT TO IMPACT LOADING

Abstract

The presented article is a contribution to the discussion concerning nuclear safety which has intensified after the Fukushima Daiichi nuclear disaster. A parametric study concerning various materials, containment wall thicknesses and different aircraft speeds at the time of impact was performed. The aim of this study was to establish damage extent of various variants of a containment structure. Containment damage was evaluated by means of the value of maximum permanent deformation and plastic strain extent. The purpose of this study was also to foster experiential suggestions for improving the explicit method in the RFEM program in order to release it for RFEM users.

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Shear Tests and Calculation of Shear Resistance with the PC Program RFEM from Thin Partition Walls of Brick in Old Buildings

Abstract

This paper is about the shear capacity of partition walls in old buildings based on shear tests which were carried out under real conditions in an existing building. There were experiments conducted on different floors and in each case, the maximum recordable horizontal force and the horizontal displacement of the respective mortar were measured. At the same time material studies and material investigations were carried out in the laboratory. The material parameters were used for the calculation of the precise shear capacity of each joint. In the shear tests, the maximum displacement of a mortar joint was determined at a maximum of two to four millimetres. Furthermore, no direct linear relationship between the theoretical load (wall above it) and the shear stress occurred could be detected in the analysis of the experiment, as it was previously assumed.

Open access
Numerical Effectiveness of Different Formulations of the Rigid Finite Element Method

Abstract

The paper presents an application of different formulations of the rigid finite element method (RFEM) to dynamic analysis of flexible beams. We discuss numerical effectiveness of the classical RFEM and an alternative approach in which continuity of displacements is preserved by means of constraint equations. The analysis is carried out for a benchmark problem of the spin-up motion in planar and spatial cases. Torsion is omitted for numerical simulations and two cases of the new approach are considered. The results obtained by means of these methods are compared with the results obtained using a nonlinear two-node superelement

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NUMERICAL ANALYSIS OF BEHAVIOUR OF COMPRESSION MEMBERS MADE OF LAMINATED STRUCTURAL GLASS

Abstract

This paper deals with design of compression members made of monolithic and laminated structural glass. Glass columns are analysed by numerical models using RFEM and ANSYS software with consideration of variable value of the interlayer shear modulus. Obtained elastic critical forces, stresses and deflections are compared with the values from the analytical calculation according to the second order theory.

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GEOMETRICALLY NONLINEAR NUMERICAL ANALYSIS OF BEAMS OF MONOSYMMETRIC THIN-WALLED CROSS-SECTIONS LOADED PERPENDICULARLY TO THE PLANE OF SYMMETRY

Abstract

The paper deals with geometrically nonlinear analysis of steel beams of monosymmetric thinwalled cross-sections loaded perpendicularly to the plane of symmetry eccentrically to the crosssection shear centre. Numerical analysis of selected transversely loaded beams is performed using Dlubal RFEM code based on finite element method. Accuracy of interaction formula for bending with lateral torsional buckling and torsion is studied.

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Structural analysis of cross-laminated timber slabs subjected to bending – state of the art

References [1] (2017). SCIA Engineer 17.1.2029 - student version [computer software]. Munich, Germany: Nemetschek. [2] (2016) DLUBAL RFEM 5.07.13 - student version [computer software]. Tiefenbach, Germany: Dlubal Software GmbH. [3] Novak, M.W., Koppelhuber, J. & Pock, K. (2014). Cross-Laminated Timber Structural Timber: Basic design and engineering principles according to Eurocode. Vienna, Austria: proHolz Austria. [4] Mestek, P., Kreuzinger, H. & Winter S. (2008). Design of Cross Laminated Timber (CLT). In 10th World

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DESIGN OF INITIAL SHAPE OF MEMBRANE STRUCTURES

Abstract

The subject of this article is the question of design and analysis of membrane structures. The first part of this article deals with the problem of form-finding. It is the problem of searching for the initial shape of membrane structure. In the second part of the article, an example of design and analysis of the membrane structure of a stadium roof is presented. This work was carried out with respect to the intention of companies Dlubal Software, s.r.o. and FEM consulting, s.r.o. to create the module for finding initial shapes of membrane structures, which would consequently be implemented into the software RFEM.

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A Discrete-Continuous Method of Mechanical System Modelling

Abstract

The paper describes a discrete-continuous method of dynamic system modelling. The presented approach is hybrid in its nature, as it combines the advantages of spatial discretization methods with those of continuous system modelling methods. In the proposed method, a three-dimensional system is discretised in two directions only, with the third direction remaining continuous. The thus obtained discrete-continuous model is described by a set of coupled partial differential equations, derived using the rigid finite element method (RFEM). For this purpose, firstly the general differential equations are written. Then these equations are converted into difference equations. The derived equations, expressed in matrix form, allow to create a global matrix for the whole system. They are solved using the distributed transfer function method. The proposed approach is illustrated with the examples of a simple beam fixed at both ends and a simply supported plate.

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Parallel Computation on Multicore Processors Using Explicit Form of the Finite Element Method and C++ Standard Libraries

Abstract

In this paper, the form of modifications of the existing sequential code written in C or C++ programming language for the calculation of various kind of structures using the explicit form of the Finite Element Method (Dynamic Relaxation Method, Explicit Dynamics) in the NEXX system is introduced. The NEXX system is the core of engineering software NEXIS, Scia Engineer, RFEM and RENEX. It has the possibilities of multithreaded running, which can now be supported at the level of native C++ programming language using standard libraries. Thanks to the high degree of abstraction that a contemporary C++ programming language provides, a respective library created in this way can be very generalized for other purposes of usage of parallelism in computational mechanics.

Open access