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Search results for: REDUCED ORDER SYSTEMS, FINITE ELEMENT ANALYSIS
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A structure and design of a novel compact UWB MIMO antenna
PublicationIn the paper, a concept and design procedure of a novel compact MIMO slot antenna is presented. In order to achieve a better filling of available space, individual antennas are constrained to a triangular shape and optimized for a reduced size. The MIMO structure is then assembled using the two of previously designed antennas in orthogonal arrangement. Surrogate-assisted numerical optimization involving variable-fidelity electromagnetic...
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Modelling and simulations in time-fractional electrodynamics based on control engineering methods
PublicationIn this paper, control engineering methods are presented with regard to modelling and simulations of signal propagation in time-fractional (TF) electrodynamics. That is, signal propagation is simulated in electromagnetic media described by Maxwell’s equations with fractional-order constitutive relations in the time domain. We demonstrate that such equations in TF electrodynamics can be considered as a continuous-time system of...
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An analytical four-layer horizontal electric current dipole model for analysing underwater electric potential in shallow seawater
PublicationThe paper presents a new analytical four‑layer (air–water–bottom–non‑conductive layer) horizontal electric dipole model which allows an accurate approximation of ship’s Underwater Electric Potential (UEP) from a sufficient depth in shallow coastal marine waters. The numerical methods, usually Finite Element Method (FEM) or Boundary Elements Method (BEM), are typically used to estimate the electric field and the distribution of...
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Mathematical approach to design 3D scaffolds for the 3D printable bone implant
PublicationThis work demonstrates that an artificial scaffold structure can be designed to exhibit mechanical properties close to the ones of real bone tissue, thus highly reducing the stress-shielding phenomenon. In this study the scan of lumbar vertebra fragment was reproduced to create a numerical 3D model (this model was called the reference bone sample). New nine 3D scaffold samples were designed and their numerical models were created....
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The structure of demand and its economic consequences for urban transport
PublicationThe structure of demand for urban transport services, determined by the share of passengers entitled to free and reduced fares, is an important factor influencing its economic condition. The aim of this article is to present the results of research into the structure of demand for urban transport as well as its economic consequences. The article begins by considering the nature of the determinants and consequences of the public...
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PRACA JAKO DOBRO INDYWIDUALNE I SPOŁECZNE
PublicationPracę definiuje się w różny sposób w zależności od przyjętego kryterium i dyscypliny naukowej, której jest ona przedmiotem badań. Może być traktowana jako źródło dochodów umożliwiających zaspokojenie potrzeb człowieka lub jako podstawowy czynnik produkcji wpływający na efektywność funkcjonowania przedsiębiorstwa. Z punktu widzenia gospodarki praca stanowi jeden z głównych czynników wzrostu i rozwoju gospodarczego. Praca pełni...
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Generative Process Planning with Reasoning based on Geometrical Product Specification
PublicationThe focus of this paper is on computer aided process planning for parts manufacture in systems of definite process capabilities, involving the use of multi-axis machining centers for parts shaping and grinding machines for finishing. It presents in particular a decision making scheme for setup determination as a part of generative process planning. The planning procedurę consists of two stages. The first stage is associated with...
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Application of polymer element in reduction of temporary steel grandstand vibrations
PublicationThe numerical analysis focused on reduction of vibrations of a temporary steel scaffolding grandstand has been conducted in this paper. These types of structures are regularly subjected to dynamic loads which, in conjunction with light and quite slender structural members, may induce dangerous vibrations. To increase their safety, temporary steel grandstands are usually strengthened with the diagonal stiffeners of tubular cross...
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Solving Boundary Value Problems for Second Order Singularly Perturbed Delay Differential Equations by ε-Approximate Fixed-Point Method
PublicationIn this paper, the boundary value problem for second order singularly perturbed delay differential equation is reduced to a fixed-point problem v = Av with a properly chosen (generally nonlinear) operator A. The unknown fixed-point v is approximated by cubic spline vh defined by its values vi = vh(ti) at grid points ti, i = 0, 1, ... ,N. The necessary for construction the cubic spline and missing the first derivatives at the boundary...
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Behaviour of Colliding Multi-Storey Buildings under Earthquake Excitation Considering Soil-Structure Interaction
PublicationThis paper investigates the coupled effect of the supporting soil flexibility and pounding between neighbouring, insufficiently separated buildings under earthquake excitation. Two adjacent three-storey structures, modelled as inelastic lumped mass systems with different structural characteristics, have been considered in the study. The models have been excited using the time history of the Kobe earthquake of 1995. A nonlinear...
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A distributed system for conducting chess games in parallel
PublicationThis paper proposes a distributed and scalable cloud based system designed to play chess games in parallel. Games can be played between chess engines alone or between clusters created by combined chess engines. The system has a built-in mechanism that compares engines, based on Elo ranking which finally presents the strength of each tested approach. If an approach needs more computational power, the design of the system allows...
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Cu supported on various oxides as a candidate catalyst for dry methane reforming in DIR-SOFCs systems
PublicationA series of Cu-support systems were tested as potential candidates for DIR-SOFC (Direct Internal Reforming SOFC) catalysts towards a dry reforming of methane (DRM). The various supports (-Al2O3, CeO2, ZrO2, SrTiO3) with comparable specific surface area (SSA), and additionally -Al2O3 with SSA an order of magnitude larger than that of the other supports has been applied. The obtained Cu-support systems were characterized in terms...
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Numerical analysis of lumbar spine injury during road safety barrier collision
PublicationPurpose: Enhancing road safety is a critical goal worldwide, necessitating the development of clear standards for road safety systems. This study focuses on lumbar spine (L-spine) compression injuries during collisions with concrete road safety barriers (RSBs). It aims to analyze internal forces during impact to understand L-spine injury biomechanics in such accidents. Methods: The research included a literature review, analyzing...
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Advanced Hysteretic Model of a Prototype Seismic Isolation System Made of Polymeric Bearings
PublicationThe present paper reports the results of acomprehensive study designed to verify the effectiveness of an advanced mathematical model in simulating the complex mechanical behaviour of a prototype seismic isolation system made of polymeric bearings (PBs). Firstly, in order to construct the seismic bearings considered in this research, a specially prepared flexible polymeric material with increased damping properties was employed....
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Mixed 4-node shell element with assumed strain and stress in 6-parameter theory
PublicationWe propose a mixed hybrid 4-node shell elements based on Hu-Washizu principle. Apart from displacements both strains and stress fields are treated as independent fields. The element is derived in the framework of a general nonlinear 6-field shell theory with drilling rotation which is dedicated to the analysis of multifold irregular shells with intersections. The novelty of the presented results stems from the fact that the measures...
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Mixed 4-node shell element with assumed strain and stress in 6-parameter theory
PublicationWe propose a mixed hybrid 4-node shell elements based on Hu-Washizu principle. Apart from displacements both strains and stress fields are treated as independent fields. The element is derived in the framework of a general nonlinear 6-field shell theory with drilling rotation which is dedicated to the analysis of multifold irregular shells with intersections. The novelty of the presented results stems from the fact that the measures...
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Technical fabrics in costruction of large scale roofs - numerical and experimental aspects
PublicationDesigning and construction of textile hanging roofs is the challenging subject for engineers. This type of structure needs geometrically and very often also physically non-linear calculations. Due to different behaviour of two families of threads (warp and weft), which during deformation can change the angle between their directions, they require special constitutive modelling. Also the loading of hanging roofs is very special....
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Generalized adaptive notch filters with frequency debiasing for tracking of polynomial phase systems
PublicationGeneralized adaptive notch filters are used for identification/tracking of quasi-periodically varying dynamic systems and can be considered an extension, to the system case, of classical adaptive notch filters. For general patterns of frequency variation the generalized adaptive notch filtering algorithms yield biased frequency estimates. We show that when system frequencies change slowly in a smooth way, the estimation bias can...
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Determination of Metals Content in Wine Samples by Inductively Coupled Plasma-Mass Spectrometry
PublicationKnowledge about the metal content of wine is very important, for many reasons. Depending on the element, its quantity varies in wine from ng/L to mg/L. Despite the fact that metals are not directly connected to the taste and aroma of the wine, their content should be determined and controlled, because excess is undesirable, and in some cases prohibited, due to potential toxicity. Several analytical procedures for metal determination...
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Multi-level models of transport systems for traffic management
PublicationThe region of Pomorskie uses a variety of tools for forecasting and analysing transport. They can be operated, calibrated and updated with data that will be collected and stored in the TRISTAR system. An initiative of the Department of Highway Engineering of the Gdansk University of Technology is designed to develop and implement an integrated and hierarchical system for forecasting and analysing transport called MST (Multilevel...
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Geometric methods in dynamical systems modelling: electrical, mechanical and control systems
PublicationRozważono zagadnienia modelowania systemów dynamicznych z zastosowaniem metod geometrii różniczkowej. Równania dynamiczne otrzymano w postaci inkluzji różniczkowych. Przestrzenie konstytucyjne przyjęto w postaci subwiązek włóknistych. Rozważono przestrzenie konstytucyjne układów elektrycznych, układów mechanicznych i układów sterowania. Podstawowe wyniki pracy dotyczą struktury przestrzeni rozwiązań rozważanych systemów.
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Robust design in delta domain for SISO plants: PI and PID controllers
PublicationW pracy przedstawiono zunifikowaną metodę numerycznie odpornej syntezy sterowników (regulatorów) działających w dyskretnym czasie w układach sterowania skalarnymi obiektami czasu ciągłego. Wykorzystano dyskretnoczasowe modele takich obiektów, oparte na tak zwanym operatorze delta, charakteryzującym się korzystnymi odpornościowymi cechami w przypadku stosowania dostatecznie małych wartości okresu próbkowania przetwarzanych sygnałów....
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Conceptual system development in a concurrent environment
PublicationW artykule omówiono możliwości wspomagania jednego z najważniejszych obszarów projektowania, a mianowicie projektowania koncepcyjnego. Rozważania te odniesiono do otoczenia inżynierii wspozadaniowej, co dodatkowo skomplikowano problemy decyzyjne podejmowane na tym etapie projektowania. Zaproponowano szereg elementów wspomagania projektowania koncepcyjnego ze szczególnym uwzględnieniem możliwości praktycznej implementacji takiego...
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I-lossless factorisations for robust H-inf-control in delta-domain
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Non-regular, incomplete and singular dynamical systems: impasse points indynamical systems
PublicationRozważono nieregularne, niezupełne i osobliwe różniczkowe systemy dynamicznez zastosowaniem metod geometrii różniczkowej.
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Robust pole placement in delta domain for SISO plans
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Qualitative and quantitative mechanisms in managing IT projects in concur-rent engineering environment
PublicationW artykule przedstawiono wprowadzenie do twardych i miękkich moetod modelowania. Nastepnie wprowadzono czytelnika do obszaru inżynierii równoległej (współzadaniowej). Całość zaproponowano jakośrodowisko wspomagania decyzji w procesach zarządzania złożonymi międzynarodowymi projektami badawczymi w obszaru Information Technology.
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Study on the accuracy of axle load spectra used for pavement design
PublicationWeigh-in-Motion (WIM) systems are used in order to reduce the number of overloaded vehicles. Data collected from WIM provide characteristics of vehicle axle loads that are crucial for pavement design as well as for the development of pavement distress prediction models. The inaccuracy of WIM data lead to erroneous estimation of traffic loads and in consequence inaccurate prediction of pavement distress process. The objective of...
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Ryszard Strzelecki prof. dr hab. inż.
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The effect of laser on metal surfaces for multidisciplinary usage in material and thermal engineering
PublicationThe subject of heat transfer and cooling systems is still a matter of contention in many different fields of science and industry. Infrigidation is much more difficult than warming, and so, much more needed in more and more different devices, starting from massive industrial machinery and air conditioning in commercial buildings, up to micro and nano-surgery tools. In fact, the size of many cooling systems is still a problem. It...
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Wpływ wysokiej osteotomii piszczelowej na mechanikę stawu kolanowego
PublicationW rozprawie podjęto próbę weryfikacji wpływu zabiegu chirurgicznego wysokiej osteotomii piszczelowej na mechanikę stawu kolanowego. Po wykonanym przeglądzie literatury, postawiono trzy hipotezy, które poddano weryfikacji na drodze badań numerycznych. Otrzymane wyniki zwalidowano poprzez badania nacisków powierzchniowych występujących w stawach kolanowych świni domowej, prowadzonych na maszynie do jednoosiowego ściskania. Praca...
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Artificial-Hand Technology—Current State of Knowledge in Designing and Forecasting Changes
PublicationThe subject of human-hand versatility has been intensively investigated for many years. Emerging robotic constructions change continuously in order to mimic natural mechanisms as accurately as possible. Such an attitude is motivated by the demand for humanoid robots with sophisticated end effectors and highly biomimic prostheses. This paper provides wide analysis of more than 80 devices that have been created over the last 40 years....
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Reliability assessment of an OVH HV power line truss transmission tower subjected to seismic loading
PublicationThe study focuses on the reliability of a transmission tower OS24 ON150 + 10, an element of an OVH HV power line, under seismic loading. In order to describe the seismic force, the real-life recording of the horizontal component of the El Centro earthquake was adopted. The amplitude and the period of this excitation are assumed random, their variation is described by Weibull distribution. The possible space state of the phenomenon...
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The ONETEP linear-scaling density functional theory program
PublicationWe present an overview of the ONETEP program for linear-scaling density functional theory (DFT) calculations with large basis set (planewave) accuracy on parallel computers. The DFT energy is computed from the density matrix, which is constructed from spatially localized orbitals we call Non-orthogonal Generalized Wannier Functions (NGWFs), expressed in terms of periodic sinc (psinc) functions. During the calculation, both the...
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Redukcja czasu analizy MZP przez ograniczenie rozmiaru rozwiązania
PublicationAnaliza drzew niezdatności jest uznaną metodą analizy bezpieczeństwa systemów. Notacja ECSDM pozwala definiować zależności czasowe między zdarzeniami drzewa oraz przeanalizować je w celu określenia zależności pomiędzy zdarzeniami z Minimalnych Zbiorów Przyczyn (MZP). Dzięki wprowadzeniu klasyfikacji zdarzeń z MZP można wyodrębnić zależności czasowe istotne dla zapobiegania wywoływania hazardu przez konkretny MZP. Pozostałe zależności...
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FEM simulations applied to the failure analysis of RC structure under the influence of municipal sewage pressure
PublicationThe paper discusses a failure mechanism of reinforced concrete (RC) structure with steel cover that failed under the influence of municipal sewage pressure. To explain the reasons of failure, in-situ measurements, laboratory experiments and comprehensive Finite Element Method (FEM) computations were performed. Non-destructive in-situ scanning tests were carried out to determine quantity and cover thickness of embedded reinforcement...
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Expedited Gradient-Based Design Closure of Antennas Using Variable-Resolution Simulations and Sparse Sensitivity Updates
PublicationNumerical optimization has been playing an increasingly important role in the design of contemporary antenna systems. Due to the shortage of design-ready theoretical models, optimization is mainly based on electromagnetic (EM) analysis, which tends to be costly. Numerous techniques have evolved to abate this cost, including surrogate-assisted frameworks for global optimization, or sparse sensitivity updates for speeding up local...
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Direct algorithm for optimizing robust MPC of drinking water distribution systems hydraulics
PublicationModel-based predictive control is an effective method for control the large scale systems [1]–[6], [8], [16], [17]. Method is based on on-line solution of the control task over the control horizon using current and past measurements, as well as the system model. Only a first element of calculated control sequence is applied to the plant. At the next sampling instant, based on new process output measurements, control procedure is...
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Implementation of power transformer controlled switching algorithm
PublicationThe article presents two new algorithms of controlled switching the power transformer. The main aim of the paper is to obtain formulas that determine the moments of closing of the circuit breaker poles. The study contains projects of control systems for both algorithms. Mathematical formulas for the time instants of the breaker poles closing were developed on the basis of electric circuit theory and magnetic circuit theory. The...
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On Applications of Fractional Derivatives in Electromagnetic Theory
PublicationIn this paper, concepts of fractional-order (FO) derivatives are analysed from the point of view of applications in the electromagnetic theory. The mathematical problems related to the FO generalization of Maxwell's equations are investigated. The most popular formulations of the fractional derivatives, i.e., Riemann-Liouville, Caputo, Grünwald-Letnikov and Marchaud definitions, are considered. Properties of these derivatives are...
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Time-Domain Description of Point-Source Acoustic Wavefields as a Useful Approach in Ultrasonic Techniques
PublicationIn traditional acoustics, field problems are usually treated in the frequency domain, broadband fields being reduced to superposition of harmonic spectrum components. However, this approach is inherently acausal and it is known that in case of arbitrary signals, the distribution-based, time-domain description can be more effective. The present paper is an attempt to expand the time-domain linear systems formalism onto space problems...
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Time-domain description of point-source acoustic wavefields as a useful approach in ultrasonic techniques
PublicationIn traditional acoustics, field problems are usually treated in the frequency domain, broadband fields being reduced to superposition of harmonic spectrum components. However, this approach is inherently acausal and it is known that in case of arbitrary signals, the distribution-based, time-domain description can be more effective. The present paper is an attempt to expand the time-domain linear systems formalism onto space problems...
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MAGNETOACOUSTIC HEATING AND STREAMING IN A PLASMA WITH FINITE ELECTRICAL CONDUCTIVITY
PublicationNonlinear effects of planar and quasi-planar magnetosound perturbations are discussed. Plasma is assumed to be an ideal gas with a finite electrical conductivity permeated by a magnetic filed orthogonal to the trajectories of gas particles. the excitation of non-wave modes in the filed of intense magnetoacoustic perturbations, i.e., magnetoaciustic heating and streaming, is discussed. The analysis includes a derivation if instantaneous...
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Selection of Organic Coating Systems for Corrosion Protection of Industrial Equipment
PublicationThe most important element of corrosion protection in industrial conditions is the protective coating system. However, selecting the right coating can often be a real problem due to the sheer number of coating manufacturers and their products on the market. A quantitative approach based on the data mining technique used to analyze the obtained multi-site exposure data has been proposed. This was demonstrated by the example of the...
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Solar Photovoltaic Energy Optimization and Challenges
PublicationThe study paper focuses on solar energy optimization approaches, as well as the obstacles and concerns that come with them. This study discusses the most current advancements in solar power generation devices in order to provide a reference for decision-makers in the field of solar plant construction throughout the world. These technologies are divided into three groups: photovoltaic, thermal, and hybrid (thermal/photovoltaic)....
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Advanced methods in biosensing: fundamentals and applications
e-Learning CoursesThis course provides instruction in the basic science and engineering conceptsrequired to understand the design and application of biosensors. Different biosensorsystems are explored, ranging from electrochemical devices, through to optical orthermal systems. Instruction is also given in the general principles of sampling andanalysis, statistical presentation and manipulation of data. The primary focus will bethe physics of biomolecule...
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Remote current measurement with FPGA digital processing
PublicationThe work presents an implementation of a modular measurement and control systemthat controls variants of mains supply of 230V electrical equipment. The system allowsto supervise power consumption in the office electronic equipment. The system detectsthe instant of the reduced power consumption by a device and makes possible itsswitch-off in order to reduce energy cost. The current is measured with integratedcurrent/voltage converters....
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Unequally-Spaced Slot Strategy for Radiation Null Reduction in Single SIW-Embedded Antenna Element
PublicationThe incorporation of higher-order modes (HOMs) can substantially augment the antenna gain and bandwidth, but this improvement is typically accompanied by compromised radiation performance including radiation nulls and higher side lobe levels. In this study, an inventive strategy is introduced to reduce the radiation nulls and the side lobe levels of a single antenna element by positioning multiple slots of the radiating element...
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Morse decompositions for a two-patch vaccination model
Open Research DataThis dataset contains selected results of rigorous numerical computations described in Section 5 of the paper "Rich bifurcation structure in a two-patch vaccination model" by D.H. Knipl, P. Pilarczyk, G. Röst, published in SIAM Journal on Applied Dynamical Systems (SIADS), Vol. 14, No. 2 (2015), pp. 980–1017, doi: 10.1137/140993934.
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The buckling analysis of a cold-formed steel C-sectional column resting on an elastic foundation
PublicationThe paper is focused on stability analysis of different models of steel cold-formed C-section column. The analysed element may be applied as a primary load-bearing member in steel trusses or silo columns. The column can be used as a support for a wall of roof plates made of corrugated sheets. The wall sheeting that restrains the column against buckling may be considered as an elastic foundation. Due to the design solutions the...