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Search results for: ENGINEERING STRUCTURES
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Deformation of thin metal and composite sheets by using anti-buckling fixture for large deformation under tension–compression cyclic loading
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Wear forms of heterogeneous electro-rheological fluids working in a hydraulic clutch system
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Analysis of a combined clutch with an electrorheological fluid
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Sensitivity analysis of thin-walled members, problems and applications
PublicationPodano przegląd problemów analizy wrażliwości konstrukcji cienkościennych. Przedstawiono metody określania pierwszej wariacji zmiennych stanu takich jak: przemieszczenia, siły wewnętrzne, reakcje, częstości i postaci drgań własnych oraz obciążeń krytycznych ze względu na zmiany parametrów konstrukcji. Rozważania ograniczono do prętów cienkościennych o otwartym bisymetrycznym przekroju poprzecznym w ramach założeń teorii prętów...
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A comparative analysis of numerically simulated and experimentally measured static responses of a floating dock
PublicationTwo numerical methods, dynamic and static analyses, are proposed to calculate the static responses of a floating dock under different ballast water distributions. Model-scale experimental tests were conducted to compare with these numerical methods. The dynamic analysis includes a 6-degree-of-freedom (6-DOF) model, a hydrostatic force model and a hydrodynamic force model to simulate the dock's freely floating processes. The dock's...
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Junctions In Shell Structures: A Review
PublicationMany shell structures used in modern technology consist of regular shell parts joined together along their common boundaries. We review different theoretical, numerical, and experimental approaches to modelling, analyses and design of the compound shell structures with junctions. Several alternative forms of boundary, continuity and jump conditions at the singular midsurface curves modelling the shell junction are reviewed. We...
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Buckling and initial post-local buckling behaviour of cold-formed channel member flange
PublicationThe initial post-buckling behaviour of a cold-formed channel member flange after its local buckling is investigated. An axially compressed column or beam subjected to pure bending is considered. The member material is assumed to follow a linear stress-strain relationship. The governing non-linear differential equation of the problem is derived using the minimum total potential energy principle. An approximate solution for the equation...
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Advanced numerical modelling for predicting residual compressive strength of corroded stiffened plates
PublicationAn advanced methodology for predicting the residual compressive strength of corroded stiffened plates is developed here using the non-linear finite element method. The non-uniform loss of a plate thickness is accounted for on a macro-scale. In contrast, mechanical properties are changed using the constitutive model to reflect the corrosion degradation impact on a micro-scale. Three different stiffened plate thicknesses are considered,...
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Stability and initial post-buckling behaviour of frame system with vertical bracings
PublicationStalowe hale są budowane jako układ ram płaskich połączonych stężeniami dachowymi i stężeniami pionowymi w postaci krzyżujących się prętów. W pracy przedstawiono analizę stateczności i zachowania pokrytycznego takiego układu poddanego działaniu obciążeń pionowych. Korzystając z warunków stacjonarności całkowitej energii potencjalnej wykazano, że punkt bifurkacji utraty stateczności jest niesymetryczny i niestateczny. Oznacza to,...
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Large thermo-elastic displacement and stability FEM analysis of multilayered plates and shells
PublicationThe paper concerns the load capacity analysis of thermally loaded multilayered plates and shells. The multilayered body is treated as an equivalent single layer whose kinematics is consistent with first order shear deformation theory. The authors focus on the thermo-elastic stability problem of the thin-walled structures. The equilibrium paths are traced with the use of Riks-Wempner-Ramm algorithm. By making use of the Tsai-Wu...
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Distortional buckling of thin-walled columns of closed quadratic cross-section
PublicationThe elastic stability of axially compressed column related to the cross-section distortion is investigated. Two kinds of closed quadratic cross-sections are taken into consideration with internal walls and without it. The governing differential equation is derived with aid of the principle of stationary total potential energy. The critical loads for the simply supported columns are found in an analytical form and compared with...
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Numerical and experimental investigation of rotational stiffness of zed-purlins connection with sandwich panels
PublicationA rotational resistant stiffness of the zed-purlins connection with sandwich panels is investigated. A simple finite element method model of the connection is proposed. The numerical analysis of the model performed by ABAQUS software, in physically linear and geometrically nonlinear ranges, leads to the rotational resistant stiffness sought. The numerical solution obtained is verified experimentally. Two variants of distribution...
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Damage detection strategies based on propagation of guided elastic waves
PublicationW pracy przedstawiono wyniki symulacji numerycznych oraz badań eksperymentalnych nad wykorzystaniemprowadzonych falsprężystych do wykrywania ilokalizacji uszkodzeń w dwu i trójwymiarowych elementach konstrukcyjnych wykonanych z materiałów izotropowych i kompozytowych.
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3D buckling analysis of a cylindrical metal bin composed of corrugated sheets strengthened by vertical stiffeners
PublicationW artykule pokazano obszerne wyniki analizy wyboczeniowej 3D przy zastosowaniu metody elementów skończonych dla silosu złożonego z blachy falistej i słupów rozmieszczonych równomiernie wokół obwodu. Obliczenia wykonano dla silosu bez i z imperfekcjami geometrycznymi i obciążeniowymi. Wyniki obliczeń porównano z Eurokodem.
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Dynamic FE simulations of buckling process in thin-walled cylindrical metal silos
PublicationW artykule przedstawiono wyniki dynamicznej analizy wyboczeniowej cienkościennych silosów metalowych o przekroju kołowym. Analizy MES wykonano dla wstępnych imperfekcji geometrycznych o różnym kształcie i amplitudzie. Wyniki analizy dynamicznej porównano z analizami statycznymi.
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Simulation of buckling process of cylindrical metal silos with flat sheets containing bulk solids.
PublicationW artykule symulowano proces wyboczenia w cylindrycznych metalowych silosach z płaskich blach wypełnionych materiałem sypkim. Wykonano analizy nieliniowe stosując MES dla silosów pustych i napełnionych. Zbadano wpływ wstępnych imperfekcji geometrycznych na nośność wyboczeniowo. Wyniki porównano z wynikami doświadczalnymi w Uniwersytecie Karlsruhe.
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Critical assessment of Eurocode approach to stability of metal cylindrical silos with corrugated walls and vertical stiffeners.
PublicationPrzedmiotem artykułu było krytyczne oszacowanie podejścia w Eurokodzie odnośnie stateczności metalowych cylindrycznych silosów z blachy falistej i słupów. Obliczenia 3D wykonane stosując MES. Symulowano blachę gładką ze słupami belkowymi o zastępczej sztywności. W obliczeniach uwzględniono falistość blachy. Pokazano, że wzory normowe znacznie odbiegają od wyników MES.
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Stability analyses of a cylindrical steel silo with corrugated sheets and columns
PublicationW artykule przedstawiono wyniki obliczeń stateczności silosów z blachy falistej ze słupami. Wykonano analizy linowe i analizy nieliniowe stosując metody elementów skończonych. W obliczeniach uwzględniono model przestrzenny powłokowy oraz uproszczony model przestrzenny z blachy ortotropowej z belkami. Wyniki numeryczne porównano z Eurokodem.
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Investigations of local/global buckling of cylindrical metal silos with corrugated sheets and open-sectional column profiles
PublicationArtykuł zajmuje się problemem lokalnego/globalnego wyboczenia w cylindrycznych metalowych silosach z blachy falistej z otwartymi cienkościennymi profilami słupowymi. Obliczenia wykonano w ramach liniowej teorii bifurkacji stosując metodę elementów skończonych w programie ABAQUS. Zbadano obszernie wpływ różnych parametrów (średnica i wysokość silosów, grubość blachy falistej, wielkość fali blachy, rozstaw słupów, przekrój słupów)...
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Determination of buckling strength of silos composed of corrugated walls and thin-walled-columns using simplified wall segment models
PublicationW artykule przedstawiono wyniki obszernych analiz numerycznych wyboczenia i stateczności metalowych silosów z blachy falistej wzmocnionych cienkościennymi słupami. Wykonano analizy liniowe i nieliniowe. Do obliczeń zaproponowano proste modele segmentów ścian zamiast skomplikowanych modeli całych silosów. Otrzymano bardzo dobrą zgodność wyników numerycznych. Wyniki obliczeń numerycznych porównano dodatkowo z wynikami normowymi.
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Buckling resistance of a metal column in a corrugated sheet silo - experiments and non-linear stability calculations
PublicationThe results of experimental and numerical tests of a single corrugated sheet silo column’s buckling resistance are presented in this study. The experiments were performed in a real silo with and without bulk solid (wheat). A very positive impact of the bulk solid on the column buckling resistance occurred. The experimental results were first compared to the buckling resistance calculated by Eurocode 3 formulae. The comparison revealed that...
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Strategies for computationally feasible multi-objective simulation-driven design of compact RF/microwave components
PublicationMulti-objective optimization is indispensable when possible trade-offs between various (and usually conflicting) design objectives are to be found. Identification of such design alternatives becomes very challenging when performance evaluation of the structure/system at hand is computationally expensive. Compact RF and microwave components are representative examples of such a situation: due to highly compressed layouts and considerable...
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Planning the City Against Barriers. Enhancing the Role of Public Spaces
PublicationContemporary cities are being fragmented by growing number of technical barriers like roads, railways, infrastructural objects, that generate variety of problems of different nature. The aim of the research is to present the issues connected with such barriers in the city and the ways of solving them. Main problems are e.g.: the destruction of the complexity of urban fabric, functional disadvantages, environmental and landscape...
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Linear viscoelastic modelling of damage-involved structural pounding during earthquakes
PublicationDamage-involved structural pounding during earthquakes has been recently intensively studied using different impact force models. The results of the previous studies indicate that the linear viscoelastic model is relatively simple yet accurate in modelling pounding-involved behaviour of structures during earthquakes. The only shortcoming of the model is a negative value of the pounding force occurring just before separation, which...
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Pounding between Inelastic Three-Storey Buildings under Seismic Excitations
PublicationStructural interactions between adjacent, insufficiently separated buildings have been repeatedly observed during damaging ground motions. This phenomenon, known as the structural pounding, may result in substantial damage or even total collapse of structures. The aim of the present paper is to show the results of the nonlinear numerical analysis focused on pounding between inelastic three-storey buildings under seismic excitations....
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A dissimilar welded joint of grade 92 steel and AISI 304L steel obtained using IN82 buttering and IN617 fller: relationship of microstructure and mechanical properties
PublicationUnfavourable operating conditions of equipment in the energy industry resulting from high-temperature loads determine the need to use special materials and technological solutions, including welding procedures. In this article, buttering using IN82 (ERNiCr-3) consumables was proposed as a method to improve the weldability of grade 92 steel joined by the gas tungsten arc welding (GTAW) process with AISI 304L (IN617 fller). The...
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Application of probabilistic tools to extend load test design of bridges prior to opening
PublicationLoad tests of bridges are widely performed in a large number of countries. Deterministic comparison of measurement results to the theoretical, FEM (finite element method)-based outcomes with possible further calibration is mostly applied. Sometimes, the data collected in the tests are also used to calibrate the reliability factors of bridge structures or their components. This work proposes to complement the stage of the load test...
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The need for linear revitalization. Gdynia case
PublicationThe aim of the article is to discuss the need of defining and implementation of the linear revitalization - the new approach related to the revitalization processes. The results of the preliminary investigations indicate that this kind of revitalization seems to be an important tool supporting city management and planning, especially in cases of cities fragmentation - causing lack of physical, social, economic and ecological cohesion....
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Removal of Pharmaceutically Active Compounds in Sequencing Batch Reactor
PublicationIn recent years, considerable attention was paid to the presence of organic micro-pollutants such as Active Pharmaceutical Ingredients (API) in the aquatic environment due to their negative impact on public health and aquatic ecosystems. Numerous papers have pointed out API presence as common constituents of effluents from Wastewater Treatment Plants (WWTPs). This is the result of various efficiencies of API removal by conventional...
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Seismic pounding between adjacent buildings: Identification of parameters, soil interaction issues and mitigation measures
PublicationStructural pounding has been observed in many previous earthquakes due to insufficient gap commonly provided between adjacent structures. The collisions usually generate large impact forces and short duration acceleration pulses which may result in significant damage to the colliding buildings. Because of that, earthquake induced structural pounding has been intensively studied and investigated for the last three decades. Results...
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Fast and reliable knowledge-based design closure of antennas by means of iterative prediction-correction scheme
PublicationA novel framework for expedited antenna optimization with an iterative prediction-correction scheme is proposed. The methodology is comprehensively validated using three real-world antenna structures: narrow-band, dual-band and wideband, optimized under various design scenarios. The keystone of the proposed approach is to reuse designs pre-optimized for various sets of performance specifications and to encode them into metamodels...
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Mitigating metal-organic framework (MOF) toxicity for biomedical applications
PublicationMetal-organic frameworks (MOFs) are a novel class of crystalline porous materials, consisting of metal ions and organic linkers. These hybrid materials are highly porous and have a large specific surface area, making them of great interest for applications in gas separation, energy storage, biomedical imaging, and drug delivery. As MOFs are being explored for biomedical applications, it is essential to comprehensively assess their...
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A comparative study on the decolorization of Tartrazine, Ponceau 4R, and Coomassie Brilliant Blue using persulfate and hydrogen peroxide based Advanced Oxidation Processes combined with Hydrodynamic Cavitation
PublicationDecolorization of Ponceau 4R, Tartrazine, and Coomassie Brilliant Blue (CBB) was studied using hybrid processes of hydrodynamic cavitation (HC) with potassium persulfate (KPS) and hydrogen peroxide (H2O2). The different properties of these dyes such as hydrophobicity, molecular structures, and molecular weights provided this opportunity to investigate the effects of these factors by comparing the decolorization values of the dyes....
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COMPARATIVE NUMERICAL ANALYSIS OF DIFFERENT STRENGTHENING SYSTEMS OF HISTORICAL BRICK ARCHES
PublicationThe article presents a comparative numerical analysis of various ways to strengthen historical brick arches. Five ways of strengthening brick arches with steel tie-rods have been proposed. Two of these involve the use of braces wrapped around pillars supporting the arch connected with a tie-rod; another two ways involve the use of the tie-rods with welded metal sheets of different sizes; the last way involves the use of the tie-rod...
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Improving the procedure of probabilistic load testing design of typical bridges based on structural response similarities
PublicationThis paper concerns load testing of typical bridge structures performed prior to operation. In-situ tests of a two-span 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...
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Architectural education and digital tools: the challenges and opportunities
PublicationEnriching architectural education with digital tools is the subject of this article. Such tools can create, support and visualise architecture. The focus in this article is on an interdisciplinary approach to media architecture (allowing variable visual content of architectural objects) and interactivity (user-space communication), revealing new possibilities in terms of human perception. The results of a survey on media architecture...
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Machine-Learning Methods for Estimating Performance of Structural Concrete Members Reinforced with Fiber-Reinforced Polymers
PublicationIn recent years, fiber-reinforced polymers (FRP) in reinforced concrete (RC) members have gained significant attention due to their exceptional properties, including lightweight construction, high specific strength, and stiffness. These attributes have found application in structures, infrastructures, wind power equipment, and various advanced civil products. However, the production process and the extensive testing required for...
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Facet effect of TiO2 nanostructures from TiOF2 and their photocatalytic activity
PublicationIn this study, special attention is focused on the design of TiO2 morphology and microstructure in the two-step preparation procedure using TiOF2 as a precursor to study their photodegradation mineralization efficiency. Firstly, TiOF2 was synthesized by a simple solvothermal method using titanium(IV) tetrafluoride, which was further used as a precursor in preparation of anatase 2D nanosheets, octahedral, decahedral, and rectangular prisms...
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Earthquake-induced pounding between equal height multi-storey buildings considering soil-structure interaction
PublicationThe present paper investigates the coupled effect of the supporting soil flexibility and pounding between neighbouring, insufficiently separated equal height 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 a suit of ground motions with different peak...
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Static Shape and Stress Control of Trusses with Optimum Time, Actuators and Actuation
PublicationTraditional shape and stress control of structures use many actuators and require enormous time to find reasonable solutions that need designers to input specific target displacement and stress. This study employs a linear technique to static shape and stress control of pin-jointed assemblies as a theoretical advancement to prior works and provides a comparative analysis against previously established works. The study evaluates...
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Load-carrying capacity of axially loaded concrete-filled steel tubular columns made of thin tubes
PublicationAn experimental investigation was conducted on 30 CFST columns. An influence of the following factors on load-carrying capacity of the investigated columns was analyzed: the column slenderness (l1 = 42, l2 = 27 and l3 = 15), the tube thickness (the reinforcement ratio was equal to 4% or 6%), the way of applying the load to CFST columns (through the concrete core or through the entire cross-section), the bond strength between a...
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A method for the three-dimensional and synchronous resolution of functional and spatial matters in architectural design
PublicationThe article discusses the issue of applied methods of teaching architectural design at Polish universities. The authors review the common methods based on conceptual drawings solving design problems in only two dimensions. After completing the floor plans' sketching process carried out in 2D way the 3D virtual models are made - seldom cardboard mock-ups - to illustrate the final spatial form of the designed object. At the Faculty...
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Micromechanical analysis of friction anisotropy in rough elastic contacts
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On shear correction factors in the non-linear theory of elastic shells
PublicationW pracy wyprowadzono analitycznie wartości korekcyjnych współczynników ścinania dla ścinania poprzecznego oraz dla momentów owinięcia w ramach nieliniowej sześcioparametrowej teorii powłok. Wartości wyprowadzono poprzez odpowiednie sformułowanie komplementarnej energii sprężystej. Na drodze analizy przy pomocy MES, badano wpływ wartości współczynników na położenie punktów bifurkacji, deformacje, całkowitą energię sprężystą układu...
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Green Synthesis of ZnO nanoparticles using Nigella sativa seed extract for antibacterial activities
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Implementation of Hermite-Ritz method and Navier’s Technique for Vibration of Functionally Graded Porous Nanobeam Embedded in Winkler-Pasternak Elastic Foundation Using bi-Helmholtz type of nonlocal elasticity
PublicationPresent study is devoted to investigating the vibration characteristics of Functionally Graded (FG) porous nanobeam embedded in an elastic substrate of Winkler-Pasternak type. Classical beam theory (CBT) or Euler-Bernoulli beam theory (EBT) has been incorporated to address the displacement of the FG nanobeam. Bi-Helmholtz type of nonlocal elasticity is being used to capture the small scale effect of the FG nanobeam. Further, the...
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Non-standard contact conditions in generalized continua: microblock contact model for a Cosserat body
PublicationGeneralized continuum theories involve non-standard boundary conditions that are associated with the additional kinematic variables introduced in those theories, e.g., higher gradients of the displacement field or additional kinematic degrees of freedom. Accordingly, formulation of a contact problem for such a continuum necessarily requires that adequate contact conditions are formulated for the additional kinematic variables and/or...
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A new anisotropic bending model for nonlinear shells: Comparison with existing models and isogeometric finite element implementation
PublicationA new nonlinear hyperelastic bending model for shells formulated directly in surface form is presented, and compared to four existing prominent bending models. Through an essential set of elementary nonlinear bending test cases, the membrane and bending stresses of each model are examined analytically. Only the proposed bending model passes all the test cases, while the other bending models either fail or only pass the test cases for...
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Electro-thermal buckling of elastically supported double-layered piezoelectric nanoplates affected by an external electric voltage
PublicationPurpose Thermal buckling of double-layered piezoelectric nanoplates has been analyzed by applying an external electric voltage on the nanoplates. The paper aims to discuss this issue. Design/methodology/approach Double-layered nanoplates are connected to each other by considering linear van der Waals forces. Nanoplates are placed on a polymer matrix. A comprehensive thermal stress function is used for investigating thermal buckling....
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Temperature influences on shear stability of a nanosize plate with piezoelectricity effect
PublicationPurpose The purpose of this paper is to predict the mechanical behavior of a piezoelectric nanoplate under shear stability by taking electric voltage into account in thermal environment. Design/methodology/approach Simplified first-order shear deformation theory has been used as a displacement field. Modified couple stress theory has been applied for considering small-size effects. An analytical solution has been taken into account...