Applied Mechanics and Materials Vol. 769

Abstract: This article focuses on the reliability analysis of a welded cylindrical tank, which is used for the storage of crude oil. The dominant load case is loading of the inner shell by hydrostatic pressure of the crude oil. Stochastic sensitivity analysis was used to study the effect of the variability of the thickness of the ith course on the stress state of adjacent courses. The computational model was developed in the programme ANSYS. Meshing was performed using SHELL181 elements. The Latin Hypercube Sampling method was implemented during analysis. Sensitivity analysis based on the evaluation of the correlation between the random plate thicknesses and the stress state was performed.

Abstract: This article describes the effect of inclination of columns on the change of stiffness of high-rise buildings with circular floor plan. Analysis was made for the building loaded by forces induced by wind and seismic loads. Various high-rise buildings with columns with different inclinations and buildings with vertical columns were analyzed from the viewpoint of horizontal displacements. The results were compared. The comparison was made with horizontal displacements of the building, where columns were inclined.

Abstract: Lamella flanges (Fig. 1) have lately grown popular with the designers of steel bridges –in their belief that these flanges provide us with the possibility of avoiding very thick flange plates in steel bridge structures. This belief is based on the assumption that the lamellas are perfectly plane and, therefore, in perfect contact everywhere, so that the loading from one lamella is transmitted into the other via pure compression, and that the perfect interaction of both lamellas is materialized by means of boundary fillet welds connecting both of the two lamellas. This simple assumption is, however, far from reality: it is not in the means of steel fabricators, not even in the means of those which are very progressively equipped, to produce perfectly plane flange lamellas. Then both lamellas exhibit unavoidable initial curvatures, which in combination form a gap between the lamellas, and consequently the directly loaded lamella is pressed into this gap. As the loading acting on every bridge is many times repeated, the aforesaid phenomenon is also many times repeated, (we can say that the lamellas „breathe“), and then an unavoidable cumulative damage process in the lamellas comes to being.

Abstract: The aim of this paper is an introduction to a very specific area of civil engineering, which is known as tensile structures (structures acting only in tension). These structures are associated with unique aspects of their design. As a result of practically zero bending stiffness, it is not possible to separate the shape and the static analysis of these structures. Shape generation is the aim of the process well known as form-finding. As a consequence of these and many other facts, it is necessary in this case to use a special way of design process, which abounds in many differences in comparison with usual design process.

Abstract: Repairs of historical timber structures lead to connecting existing and new beams. The requirements for beam authenticity make use of older ways of connecting. The first type is the splice of beams in bending with the scarf joint, rafters and tie-beams are joined with the dovetail and, finally, the connection of the main joist with the strut is by the mortise carve.

Abstract: Static and dynamic analysis of the high-rise (24-storey) building is discussed in this paper. The influence of the change of load-bearing system on its stiffness in the case of seismic event was detected. Two different load-bearing systems were chosen – the wall system (alt.1) and the skeleton system (alt.2). Finite element method was used for the solution of 3D computing models. Short description of the building, used material, applied load, a type of the subsoil and obtained results are mentioned. Dynamic analysis was repeated for four various seismic areas in Slovakia.

Abstract: The paper deals with torsional-flexural buckling of thin-walled metal members with mono-symmetric open cross-sections and with various torsional and flexural boundary conditions. An approximate method, which is located in recent norms, for calculation of critical forces of such member cases are focused on. For chosen type of mono-symmetric open cross-section a parametric study of critical forces by the approximate method and by as a reference taken FEM method are performed.

Abstract: Von Misses truss is one of the best examples to explain nature of non-linear solution and define the snap-through. Linear buckling analysis and nonlinear finite element approaches are compared in presented paper. At the present time theoretical models for the evaluation of the ultimate load assume a structure with imperfections. The peculiarities of the effect of the magnitude and mode of initial imperfections are investigated. Effect of member stiffness on the load level in critical point of nonlinear solution, as well as the relative position with respect to the critical load from buckling analysis are analyzed. To obtain the nonlinear equilibrium paths, Newton-Raphson iteration algorithm has been used. Obtained results are compared with those gained using ANSYS system.

Abstract: The article deals with the computational model of an elastic von Mises planar truss. The description of a mathematical concept, which is intended for the creation of computational programmes based on a finite number of segments, is presented. The mathematical solution is suitable for the analysis of load-deflection curves. Structural deformation is evaluated by seeking the minimal potential energy. The article examines the effects of change in the vertical displacement of the top joint on strut axes. The step by step incremental method is used in combination with the Newton-Raphson method. The presented study is aimed at the evaluation of the force in the bifurcation point, which determines the moment when loading of the model causes passing from the pre-critical effect (attainment of maximum vertical load action) to the post-critical effect. Symmetric and asymmetric initial axis imperfections are considered and relevant symmetric and asymmetric shapes of buckling are identified. The stability problem of the von Mises truss is discussed in connection with the random effects of imperfections.