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Search results for: THIN-WALLED BARS
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Clear cell carcinoma, NOS - Female, 79 - Tissue image [6070730010418211]
Open Research DataThis is the histopathological image of KIDNEY tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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Clear cell carcinoma, NOS - Female, 79 - Tissue image [6070730010419451]
Open Research DataThis is the histopathological image of KIDNEY tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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Clear cell carcinoma, NOS - Female, 79 - Tissue image [6070730010417951]
Open Research DataThis is the histopathological image of KIDNEY tissue sample obtained in Medical University Gdańsk and deposited in ZMDL-GUMED. The sample image was taken using: Pannoramic 250 3DHistech slide scanner (20x magnification) and saved to DICOM format.
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Torsional buckling and post-buckling of columns made of aluminium alloy
PublicationThe paper concerns torsional buckling and the initial post-buckling of axially compressed thin-walled aluminium alloy columns with bisymmetrical cross-section. It is assumed that the column material behaviour is described by the Ramberg–Osgood constitutive equation in non-linear elastic range. The stationary total energy principle is used to derive the governing non-linear differential equation. An approximate solution of the equation...
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Reinforced concrete thin wall dome after eighty years of operation in maritime climate environment
PublicationThe paper presents a description of the construction elements of the Gdynia Seaport main hall dome. Firstly, it provides information about the technical condition of the dome’s structure. Secondly, it examines the strength analysis of the thin-walled reinforced concrete dome covering. Throughout the last 80 years the building has been exposed to an unfavourable marine climate. The analysis of the state of stress and deformations...
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Local buckling of compressed flange of cold-formed channel members made of aluminum alloy
PublicationThe paper deals with local buckling of a compressed single flange of thin-walled channel cold- formed columns and beams made of aluminum alloy. Material is described by means of the Ramberg-Osgood constitutive equation. Axial compression of the columns and beams undergoing bending is taken into consid- eration. A simple model of the member flange in the form a long beam elastically connected to the web is used to find the critical...
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Buckling analyses of metal cylindrical silos containing bulk solids during filling
PublicationThe paper presents 3D results on stability of thin-walled cylindrical metal silos made of isotropic rolled and corrugated plates containing bulk solids. The behavior of bulk solids was described using a hypoplastic constitutive model. Nonlinear finite element (FE) analyses with both geometric and material nonlinearity were performed with a perfect and an imperfect silo shell wherein initial geometric imperfections were taken into...
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Preliminary experimental research on stability of truss' joint with positive eccentricity
PublicationRecently, a very large interest in lightweight steel structures made from cold-formed sections has been noticeable. In the design practice, a large emphasis is put on rational shaping of both the thin-walled elements and constructions designed on them. The aim of this paper is to present the methodology for preparation of experimental research that model the behaviour of members in trusses made of cold-formed sections with positive...
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Buckling of simplified models of silo with corrugated walls and vertical stiffeners
PublicationThe paper deals with buckling of cylindrical silos composed of corrugated sheets and vertical stiffeners (columns). Comprehensive finite element analyses were carried out for a perfect silo by means of a linear buckling approach. Corrugated walls were simulated as an equivalent orthotropic shell and vertical thin-walled columns as beam elements. Calculations for perfect silos with different numbers of columns made it possible to...
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The Influence of Selected Parameters of Numerical Modelling on Strains and Stresses at Weld Toe Notch
PublicationLatest development in the field of welding technology and prefabrication enabled massive production of thin-walled sandwich structures. Multi-layered sandwich structures are fabricated with the use of high-power CO2 lasers, friction welding, arc welding, hybrid welding, or other technique designed for the special purpose. Steel or aluminium alloy plates with thickness between 1 and 5 mm are connected by internal stiffeners. Strength...
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FEM modelling of stress and strain distribution in weld joints of steel sandwich panels
PublicationThe development of laser welding technology has enabled the mass production of thin-walled structures, including steel sandwich panels. The technology of joining plating panels with stiffeners by welding allows us to create joints with a specific geometry and material properties. In comparison with other types of joints, laser welds are characterized by their specific behaviour under cyclic load and, as a consequence, a different...
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The Influence of Modelling Material Zones on Strains and Stresses at Weld Toe Notch
PublicationThe latest development in the field of welding technology enabled prefabrication of thin-walled sandwich structures in an industrial scale. Sandwich structures fabricated of steel, or aluminium alloy plates and stiffeners are welded with the use of hi-power CO2 lasers. Strength analysis of such structures with the use of finite element method needs proper material modelling.In this paper the material model of steel sandwich panel...
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A higher order transversely deformable shell-type spectral finite element for dynamic analysis of isotropic structures
PublicationThis paper deals with certain aspects related to the dynamic behaviour of isotropic shell-like structures analysed by the use of a higher order transversely deformable shell-type spectral finite element newly formulated and the approach known as the Time-domain Spectral Finite Element Method (TD-SFEM). Although recently this spectral approach is reported in the literature as a very powerful numerical tool used to solve various...
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Simple Computational Methods in Predicting Limit Load of High-Strength Cold-Formed Sections due to Local Buckling: A Case Study
PublicationCold-formed thin-walled sections are prone to local buckling caused by residual stresses, geometrical imperfections and inconsistency of material properties. We present a real case of buckling failure and conduct a numerical and experimental study aimed to identify methods capable of predicting such failures. It is important because designers of structures are getting more FEA-oriented and tend to avoid lengthy procedures of cold-formed...
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Application of linear buckling sensitivity analysis to economic design of cylindrical steel silos composed of corrugated sheets and columns
PublicationThe paper deals with global stability of steel cylindrical silos composed of corrugated walls and vertical columns with loads imposed by a bulk solid following Eurocode 1. The optimum silo design with respect to the steel weight was based on a sensitivity analysis method. The changes of silo column profiles at each design step were performed by means of influence lines for the buckling load factor due to the unit column bending...
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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...
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2022-2023 - Strenght of materials towards applications, PG_00053661
e-Learning CoursesThe course is mainly dedicated to the DAPE Students. From the theoretical point of view the course consists of the following problems to be discussed during the lectures and exercises: -fundamentals of strength of materials -basic structures and environment -loads on structures -strength of materials: tension, stress, analysis of stress and strain, bending moments and shearing forces, longitudinal and shearing stress in beams,...
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Strenght of materials towards applications , PG_00053661
e-Learning CoursesThe course is dedicated to the DAPE WIMiO Students. From the theoretical point of view the course consists of the following problems to be discussed during the lectures: -fundamentals of strength of materials -basic structures and environment -loads on structures -strength of materials: tension, stress, analysis of stress and strain, bending moments and shearing forces, longitudinal and shearing stress in beams, bending stress...
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Dome over the Gdynia seaport building
PublicationThe paper presents the description of structure and the selected problems of the technical condition, as well as the strength analysis of the thin-walled reinforced concrete shell which has been making a covering of the main hall of the Gdynia Seaport Building through the last 80 years. The rectangle projection of four single curvature shells of the dome was shaped out of mutual perpendicular intersection of two cylindrical shells. The...
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A Critical Reanalysis of Uncontrollable Washboarding Phenomenon in Metal Band Sawing
PublicationThe article analyzes the cutting process of hard bars. Investigations conducted in industrial conditions demonstrated the presence of surface errors in the machined workpieces in the form of washboard patterns. The purpose of this study was to analyze the results of cutting on band sawing machines with different band saw blades. The cutting processes were conducted on three different horizontal band sawing machine types. Analyzed...
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Electrochemical synthesis and characterization of nanocomposites based on poly(3,4-ethylenedioxythiophene) and functionalized carbon nanotubes
PublicationThis work is focused on new composite materials consisting of poly(3,4-ethylenedioxythiophene) (pEDOT) and functionalized multi-walled carbon nanotubes synthesized electrochemically. Three types of composites were synthesized: the first one containing carbon nanotubes with carboxyl groups (covalent functionalization), the second one containing oxidized carbon nanotubes ox-MWCNTs (with different oxygen-rich polar groups) (covalent...
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STRENGTH of MATERIALS TOWARDS APPLICATIONS (2024)
e-Learning CoursesThe SMTA DATE Course consists of the following problems to be discussed during the lectures: - Introduction to strength of materials towards applications - Fundamentals of modelling in strength of materials towards applications - Materials and basic structures - Fundamentals of modelling in strength of materials towards applications - Definition of environment and loads - General, energy-based and advanced methods for analysis...
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A random field-based simulational identification of possible levels of material imperfections of adhesive-bonded joints
PublicationRecently, structural adhesives have become significant in the shaping of structural elements, especially in thin-walled structures, where they replace or supplement traditional connection methods. However, adhesive-bonded joints are highly susceptible to internal structural imperfections due to their application technique and the nature of the adhesive. These material inconsistencies impact the strength parameters and the mechanical...
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The effect of numerical 2D and 3D FEM element modelling on strain and stress distributions at laser weld notches in steel sandwich type panels
PublicationLike other means of transport, merchant ships face the problem of increasing requirements concerning the environment protection, which, among other issues, implies the reduction of fuel consumption by the ship. Here, the conventional approach which consists in making use of higher strength steels to decrease the mass of the ship hull can be complemented by the use of new steel structures of sandwich panel type. However, the lack...
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Experimental research on over-laminated steel sandwich panel connection to determine the form of fatigue failure
PublicationThe novel means of transport need to meet rising both the economic and ecologic requirements. In recent years the International Maritime Organization (IMO) introduced new measure of ship energy efficiency (the EEDI index), as well as new regulations regarding higher quality of fuel (so called Tier limits). It resulted in much higher interest of the technological development of ships. One of the solution having great potential is...
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Selected local stability problems of channel section flanges made of aluminium alloys
PublicationThe paper addresses the issue of local buckling of compressed flanges of cold-formed thin-walled channel columns and beams with nonstandard flanges composed of aluminium alloys. The material behaviour follows the Ramberg–Osgood law. It should be noted that the proposed solution may be also applied for other materials, for example: stainless steel, carbon steel. The paper is motivated by an increasing interest in nonstandard cold-formed...
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Experimental and numerical identification of corrosion degradation of ageing structural components
PublicationThe study presents experimental and numerical identification of corrosion degradation of thin-walled structural components employing guided wave propagation. The steel structural components are subjected to through-thickness varying corrosion degradation levels. The developed approach using the non-destructive guided wave-propagation quantifies the equivalent average corrosion degradation level by exploring a limited number of...
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Rotational Molding of Linear Low-Density Polyethylene Composites Filled with Wheat Bran
PublicationApplication of lignocellulosic fillers in the manufacturing of wood polymer composites (WPCs) is a very popular trend of research, however it is still rarely observed in the case of rotational molding. The present study aimed to analyze the impact of wheat bran content (from 2.5 wt.% to 20 wt.%) on the performance of rotationally-molded composites based on a linear low-density polyethylene (LLDPE) matrix. Microscopic structure...
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THIN SOLID FILMS
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Vibration Surveillance System with Variable Stiffness Holder for Milling Flexible Details
PublicationEfficient milling of the flexible details (i.e. rotor blades, thin-walled elements) using slender ball-end tools is a difficult task due to possibility of vibration occurrence. Because of the existence of certain conditions (small depths of cutting, regeneration phenomena), cutting process may lose stability and self-excited chatter vibration may appear. Frequency of the chatter vibration is close to dominant natural frequency...
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On a 3D material modelling of smart nanocomposite structures
PublicationSmart composites (SCs) are utilized in electro-mechanical systems such as actuators and energy harvesters. Typically, thin-walled components such as beams, plates, and shells are employed as structural elements to achieve the mechanical behavior desired in these composites. SCs exhibit various advanced properties, ranging from lower order phenomena like piezoelectricity and piezomagneticity, to higher order effects including flexoelectricity...
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Nonlocal Models of Plates and Shells with Applications in Micro- and Nanomechanics
PublicationNowadays, the use of small-scale structures in micro/nanomachines has become more and more widespread. The most important applications of such small-sized parts are in micro-electro-mechanical systems (MEMS) as well as nano-electro-mechanical systems (NEMS) as actuators, sensors, energy harvesters. For example, nanosensors are nanoscale devices that measure physical quantities and convert these to signals that can be detected and...
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DEFORMATIONS OF INNOVATIVE COLD-FORMED GEB SECTIONS
PublicationPermanent urban growth of the world of today world implies demanding challenges for the steel construction industry. Nowadays, one of the most important issues is the cost optimization of steel structures. Since the weight of building materials is a major component of the total cost, engineers and designers try to reduce structural weight, without compromising durability and sustainability of a steel structure. Therefore, light...
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Flexural behaviour of concrete slabs reinforced with FRP bars in experiments and according to aci ACI 440.1R guide
PublicationThe paper presents research conducted on two concrete slabs reinforced with the carbon composite bars and two other concrete slabs reinforced with basalt composite bars. The carbon bars were plain, while the basalt ones were ribbed. The slabs were experimentally investigated in the flexural state of effort with the concentrated forces applied. The results are compared with the analytical solution proposed in the guide ACI 440.1R-06...
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Bearing Capacity of aluminum bars with built-up cross section and glued or welded connections
PublicationThe paper is focused on numerical analysis and experimental test of aluminum bars with glued and welded connections between separate members. The connection properties were tested experimentally. The numerical analysis were conducted for the beam and shell model of the structure. The shape and magnitude of initial geometric imperfection was taken into account
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STABILITY AND LOAD BEARING CAPACITY OF A BARS WITH BUILT UP CROSS SECTION AND ELASTIC SUPPORTS
PublicationThe present paper is devoted to the numerical analysis and experimental tests of compressed bars with built–up cross section which are commonly used as a top chord of the roof trusses. The significant impact on carrying capacity for that kind of elements in case of out-of-plane buckling is appropriate choice of battens which are used to provide interaction between separate members. Linear buckling analysis results and nonlinear static...
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Guided ultrasonic waves for detection of debonding in bars partially embedded in grout
PublicationThis paper deals with theoretical, numerical and experimental investigations of guided wave propagation in multilayered cylindrical bars with pre-existing debonding. The research focuses on a complex description of the nature of the wave phenomena occurring in a debonded specimen with a special emphasis on the influence of the location of damage on the wave conversion and diffraction. Experimental non-destructive and destructive...
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The effect of external load on ultrasonic wave attenuation in steel bars under bending stresses
PublicationThe stress state in deformed solids has a significant impact on the attenuation of an ultrasonic wave propagating through the medium. Measuring a signal with certain attenuation characteristics can therefore provide useful diagnostic information about the stress state in the structure. In this work, basic principles behind a novel attenuation-based diagnostic framework are introduced. An experimental study on steel bars under three-point...
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Derivatization of single-walled carbon nanotubes with redox mediator biocatalytic oxygen electrodes
PublicationSingle-walled carbon nanotubes were covalently modyfied with a redox mediator derived from 2,2'-azino-bis-(3-ethylbenzothiazole)-6-sulfonic acid.
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Buckling analysis of a non-concentric double-walled carbon nanotube
PublicationOn the basis of a theoretical study, this research incorporates an eccentricity into a system of compressed double-walled carbon nanotubes (DWCNTs). In order to formulate the stability equations, a kinematic displacement with reference to the classical beam hypothesis is utilized. Furthermore, the influence of nanoscale size is taken into account with regard to the nonlocal approach of strain gradient and the van der Waals interaction...
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Structure and optical parameters of Eu doped tellurium oxide thin films prepared by reactive magnetron sputtering method
PublicationIn this work the structural properties and photoluminescence of tellurium dioxide thin films doped by europium were described. Thin films were deposited by magnetron sputtering method and simultaneously heated at 200 °C. Presence of Eu ions and their valence states was confirmed by X-ray photoemission spectroscopy measurements. The structure of the films as well as the influence of europium dopant on crystalline structure of the...
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Properties of Barium Cerate-Zirconate Thin Films
PublicationIn this work, we review several experimental results showing the electrical properties of barium cerate-zirconate thin films and discuss them in view of the possible influence of various factors on their properties. Most of the presented Ba(Ce, Zr, Y)O3 thin films were formed by the pulsed laser deposition (PLD) technique, however thin films prepared using other methods, like RF magnetron sputtering, electron-beam deposition, powder...
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Deposition and growth of thin ceramic films
Publication: Thin ceramic films play an important role in modern technology. One of the more utilized methods of deposition of ceramic films is spin coating. In this paper we investigate optimal deposition parameters for LaNi0.6Fe0.4O3−δ thin layers spin coated from a polymeric precursor. The quality of the obtained layers is checked using scanning electron microscopy. Additionally, we investigate the growth of grains in ceramic films annealed at...
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Thermal Instability of Gold Thin Films
PublicationThe disintegration of a continuous metallic thin film leads to the formation of isolated islands, which can be used for the preparation of plasmonic structures. The transformation mechanism is driven by a thermally accelerated diffusion that leads to the minimalization of surface free energy in the system. In this paper, we report the results of our study on the disintegration of gold thin film and the formation of nanoislands...
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Influence of LCVD technologicalparameters on propertiesof polyazomethine thin films
PublicationPurpose: The aim of this paper is to show influence of technological parameters (temperature and gas streamintensity) of low-temperature chemical vapour deposition (LCVD) on optical properties and morphology ofpolyazomethine thin films.Design/methodology/approach: Thin layers of poly (1,4-phenylene-methylenenitrilo-1,4-phenylenenitrilo-methylene) (PPI) were prepared by low temperature LCVD method with use of argon as a transport...
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Reconstruction of thin films polyazomethine based on microscopic images
PublicationPurpose: The aim of this paper was to investigate changes in surface morphology of thin films ofpolyazomethine PPI. Thin films were prepared using low-temperature chemical vapor deposition (CVD)method.Design/methodology/approach: The changes in surface topography was observed by the atomicforce microscope AFM and scanning electron microscope SEM. The results of roughness have beenprepared in the software WSxM NanoTec Spanish...
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Fracture Surface Behavior of 34CrNiMo6 High-Strength Steel Bars with Blind Holes under Bending-Torsion Fatigue
PublicationThe present study evaluates the fracture surface response of fatigued 34CrNiMo6 steel bars with transverse blind holes subjected to bending with torsion loading. The analysis of the geometric product specification was performed by means of height parameters Sx, functional volume parameters Vx, and fractal dimension Df. Surface topography measurements were carried out using an optical profilometer with focus variation technology....
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Tailoring electronic structure of polyazomethines thin films
PublicationPurpose: The aim of this work is to show how electronic properties of polyazomethine thin films deposited bychemical vapor deposition method (CVD) can be tailored by manipulating technological parameters of pristinefilms preparation as well as modifying them while the as-prepared films put into iodine atmosphere.Design/methodology/approach: The recent achievements in the field of designing and preparation methods tobe used while...
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On dielectric spectra of thin copper phthalocyanine films
PublicationPraca przedstawia niskosygnałowe widma dielektryczne, w zakresie częstotliwości 25 Hz-1 MHz, układów kanapkowych takich jak złoto/ftalocyjanina miedzi/magnez i złoto/ftalocyjanina miedzi/złoto.Przeprowadzona analiza umożliwiła odróżnienie w odpowiedzi dielektrycznej oporności elektrod i polaryzacji sieci od procesów związanych z transportem elektrycznych, takich jak relaksacja nośników ładunku w obszarze ładunku przestrzennego...
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Physical properties of polyazomethine thin films doped with iodine
PublicationPurpose: The aim of this paper is to show influence of doping 1,4-phenylene-methylenenitrilo-1,4-phenylenenitrilomethylene (PPI) with iodine and to propose doping mechanism and its impact on electronicstructure of doped PPI thin films.Design/methodology/approach: Influence of iodine doping on electronic structure of polyazomethine thinfilms was investigated. Optical absorption spectra, XRD spectra and AFM images of doped PPI...