The surfacing technologies are used for constitution of protection layer against wear and is destined for obtaining coating with high

hardness. Among many weldings methods currently used to obtain the hard surface layer one of the most effective way of hardfacing is

using flux cored arc welding. This additional material gives more possibilities to make expected hard surface layer.

Chemical composition, property and economic factors obtained in flux cored wire are much richer in comparison to these obtained with

other additional materials. This is the reason why flux cored wires give possibilities of application this kind of material for improving

surface in different sectors of industry.

In the present paper the imperfection in the layers was used for hardfacing process in different situations to show the possible application

in the surface layer. The work presents studies of imperfection of the welds, contains the picture of microstructures, macrostructures and

shows the results of checking by visual and penetrant testing methods.

The approach to numerical analyses was changed by the introduction of Eurocodes . The EN 1993-1-6 standard allows taking into account imperfections on the shape of a buckling form from a linear elastic bifurcation analysis. The article analyses the first ten forms of imperfection from a linear elastic bifurcation analysis on the reduction of the capacity of a cylindrical shell. Calculations were made using finite element methods.

The essential problem in the process of technological prestressing is the imperfection of web sheets. These elements made of relatively large sheets (about 2 meters high) show significant imperfections of the shape and flatness. Initial deflections have the value equal several times the web thickness, but they tend to grow in the process of straightening. Such a case can particularly occur when stresses that compress the shield of the web sheet between diaphragms are close to the critical buckling stress. Experiments were carried out in a real object. The box girder having I I .Om span and 1.8 m in its height was prestressed by welding the straps on the bottom flange and on the web in the vicinity of the bottom llange. Results of performed investigations are the subject of the paper.

The rotating machines with overhung rotors form a broad class of devices used in many types of industry. For this kind of rotor machine in the paper, there is investigated an influence of dynamic and static unbalance of a rotor, parallel and angular misalignments of shafts, and inner anisotropy of rigid couplings on system dynamic responses. The considerations are performed through a hybrid structural model of the machine rotor-shaft system, consisting of continuous beam finite elements and discrete oscillators. Numerical calculations are carried out for parameters characterizing a heavy blower applied in the mining industry. The main goal of the research is to assess the sensitivity of the imperfections mentioned above on excitation severity of rotor-shaft lateral vibrations and motion stability of the machine in question.

The purpose of the following paper is to present the experimental field investigations in jointless railway track subjected to the author’s generated imperfections on its static work. The main concept for the executed investigations is to induce an intentional imperfection (both a concave and convex irregularity) in an actual railway track, propose a way of appropriate measurement (using the PONTOS system), and utilize author’s field investigations results to calibrate necessary parameters for theoretical calculations. An experimental formula describing the value of the force transferred from the rail to the railway sleeper on the grounds of the survey site caused by a locomotive is provided. Furthermore, the deflection of the chosen railway rail and sleeper due to the generated imperfection is subjected to analysis. Finally the objective of the present consideration is to resolve the calculations into the beam element such that the results can be used in computational railway practice. The scheme of the so-called a “hanging sleeper” is particularly unfavourable, a gap arises between the sleeper and the foundation, for which the significant changes appear, especially in the rail deflections and stresses. A work scheme of the railway track elements is described on the generated short concave and convex irregularity.

In the present paper, an analysis uf lower bound estimation of the load carrying capacity of structures with intermediate stiffeners is undertaken. Thin-walled structures with intermediate stiffeners in the elastic range, being under axial compression and a bending moment, are examined on the basis of the Byskov and Hutchinson's method [4] and the co-operation between all the walls of the considered structures is shown. The structures are assumed to be simply supported at the ends. The study is based on the numerical method 01· the transition matrix using Godunov's orthogonalization [2]. Instead of the finite strip method, the exact transition matrix method is used in this case. In the presented method for lower bound estimation uf the load carrying capacity of structures, it is postulated that the reduced local critical load should be determined taking into account the global pre-critical bending within the first order non-linear approximation to the theory of the interactive buckling of the structure. The results are compared to those obtained from the design code and the data reported by other authors. The present paper is a continuation of papers [9], [ 11], [ 19], where the interactive buckling of thin-walled beam-columns with central intermediate stiffeners in the first and the second order approximation was considered. The most important advantage of this method is that it enables us to describe a complete range of behaviour ot· thin-walled structures from all global (flexural. flexural-torsional, lateral, distortional and their combinations) to local stability. In the solution obtained, the effects of interaction of modes, the transformation of buckling modes with an increase in load, the shear lag phenomenon and also the effect of cross-sectional distortions arc included.

The problem of optimal design of a steel plated girder according to the Eurocode 3 is considered. Code regulations admit the Finite Element Analysis (FEA) in designing plated structures with variable cross-sections. A technique of determining an approximate solution to the optimization problem is presented. It is determined a solution of a control theory optimization task, in which Eurocode requirements regarding the Ultimate Limit State (bearing capacity, local and global stability) as well as Serviceability Limit State (flexural rigidity) are used as appropriate inequality constraints. Static analysis is performed within the framework of linear elasticity and Bernoulli-Euler beam theory making an account for second-order effects due to prescribed imperfections. Obtained solutions, after regularization, may be used for direct verification with the use of FEA or as the first guess for iterative topology optimization algorithms. Code requirements governing the determination of optimal shape are visualized in the constraint activity diagram, which is a proposed tool for analysis of optimization process.

This paper concerns load testing of typical bridge structures performed prior to operation. In-situ tests of a twospan post-tensioned bridge loaded with three vehicles of 38-ton mass each formed the input of this study. On the basis of the results of these measurements an advanced FEM model of the structure was developed for which the sensitivity analysis was performed for chosen uncertainty sources. Three uncorrelated random variables representing material uncertainties, imperfections of positioning and total mass of loading vehicles were indicated. Afterwards, two alternative FE models were created based on a fully parametrised geometry of the bridge, differing by a chosen global parameter – the skew angle of the structure. All three solid models were subjected to probabilistic analyses with the use of second-order Response Surface Method in order to define the features of structural response of the models. It was observed that both the ranges of expected deflections and their corresponding mean values decreased with an increase of the skewness of the bridge models. Meanwhile, the coefficient of variation and relative difference between the mean value and boundary quantiles of the ranges remain insensitive to the changes in the skew angle. Owing to this, a procedure was formulated to simplify the process of load testing design of typical bridges differing by a chosen global parameter. The procedure allows - if certain conditions are fulfilled - to perform probabilistic calculations only once and use the indicated probabilistic parameters in the design of other bridges for which calculations can be performed deterministically.

In the paper there the laboratory tests of interaction between thin-walled beams of the Z crosssection and the sandwich panels with PIR foam core are presented. The different numbers of connectors (0, 4, and 8) were used to connect the sandwich panels with the thin-walled beams. Furthermore, the parallel and perpendicular to the longitudinal axis of the thin-walled beam load arrangement was analysed. The research provides a qualitative and quantitative comparison of the mentioned experiments using the ultimate capacity, the deformation capacity, and the stiffness. In the second part of the paper, the numerical analysis of the thin-walled beam was also performed. The beam was modelled as a shell element and loaded in two ways, which corresponded to the loading scenario during laboratory tests (uniformly distributed and concentrated loads). The results of the numerical calculations of the beam without lateral stabilization were compared with the laboratory results of the beam stabilized by the sandwich panels.

Double corrugated, self-supporting K-span arch structures are now commonly used globally to make roofs for building structures, as an alternative to traditional solutions. The K-span system has become popular mainly due to the simple and cheap method of its manufacturing and quick installation. Nowadays, new versions of the system are created but still there is no valid design method. Design difficulties are among the causes of failures or even collapses of such structures. Back in the 1970s, the first studies were developed concerning computational analyses of double corrugated arch roofs. They laid grounds for the development of contemporary K-span system technology but have since lost their practical advantages due to changing engineering conditions. The paper presents a review of research and computational methods concerning double corrugated arch structures. The paper discusses selected scientific studies, which were used as the basis for the development of research and computational methods, and their contemporary continuation. Directions for further research and analyses are also presented which could contribute to the future development of science and engineering in the area and could provide inspiration for future studies.