Filtry
wszystkich: 1731
-
Katalog
wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: continuum contact mechanics
-
Robustness of contact-less optical method, used for measuring contact wire position in changeable lighting conditions
PublikacjaThe article presents verification of robustness of contactless method based on 2D image camera, which is used to measure catenary contact wire position in changeable ambient lighting conditions. Robustness in changeable lighting conditions is ensured through the combination of advanced image processing for background information removal and the algorithm of error correction. This algorithm detects incorrect images and substitutes...
-
Jacek Tejchman prof. dr hab. inż.
Osoby -
Application of fracture mechanics for energetic effects predictions while wood sawing
PublikacjaIn the classical approach, energetic effects (cutting forces and cutting power) of wood sawing process are generally calculated on the basis of the specific cutting resistance, which is in the case of wood cutting the function of more or less important factors. On the other hand, cutting forces (power) could be considered from a point of view of modern fracture mechanics. Cutting forces may be employed to determine not only toughness...
-
CUTTING POWER FORECASTING WHILE WOOD SAWING: FRACTURE MECHANICS APPROACH AND AXELSSON’S MODEL COMPARISON
PublikacjaIn the classical approach, energetic effects (cutting forces and cutting power) of wood sawing process are generally calculated on the basis of the specific cutting resistance, which is in the case of wood cutting the function of more or less important factors. On the other hand, cutting forces (power) could be considered from a point of view of modern fracture mechanics. Another way is to forecast cutting power consumption on...
-
Continuum models for pantographic blocks with second gradient energies which are incomplete
PublikacjaWe postulate a deformation energy for describing the mechanical behavior of so called pantographic blocks, that is bodies constituted by stacking of layers of pantographic sheets. We remark that the pantographic effect is limited in the plane of pantographic sheets and therefore only the second derivatives of transverse displacements along the pantographic fibers appear in the chosen deformation energy. We use this novel energy...
-
Application of Fracture Mechanics for Energetic Effects Predictions While Wood Sawing
PublikacjaIn the classical approach, energetic effects (cutting forces and cutting power) of wood sawing process are generally calculated on the basis of the specific cutting resistance, which is in the case of wood cutting the function of more or less important factors. On the other hand, cutting forces (or power - more interesting from energetic point of view) could be considered from a point of view of modern fracture mechanics. Cutting...
-
Anti-plane surface waves in media with surface structure: Discrete vs. continuum model
PublikacjaWe present a comparison of the dispersion relations derived for anti-plane surface waves using the two distinct approaches of the surface elasticity vis-a-vis the lattice dynamics. We consider an elastic half-space with surface stresses described within the Gurtin–Murdoch model, and present a formulation of its discrete counterpart that is a square lattice half-plane with surface row of particles having mass and elastic bonds different...
-
Introduction to quantum mechanics 2022/2023
Kursy OnlineIntroduction to quantum mechanics, kierunek: Nanotechnologia, specjalność: Nanostructures and computer simulations in material science, II stopień, semestr 1
-
Introduction to quantum mechanics 2024/2025
Kursy OnlineIntroduction to quantum mechanics, kierunek: Nanotechnologia, specjalność: Nanostructures and computer simulations in material science, II stopień, semestr 1
-
Experimental verification of visual method for measuring displacements of contact line elements
PublikacjaThe increase of rail vehicles speed, as well as the increase of their power, puts high demands on the power delivery system for traction vehicles The most critical point in the vehicle's power supply circuit is the contact between the current collector and contact wires. Ensuring a reliable co-operation of the current collector and contact line, requires technical development...
-
Modelling of cutting by means of fracture mechanics
PublikacjaThe suitability of modern fracture mechanic theory was proved for the estimation of the cutting force and the cutting specific resistance. This paper shows modification of Ernst-Merchant theory and its application for determination some other properties of wood sample. This theory is acceptable for evaluation of shear yield stresses and shear plane angle. Sawing by gang saw machine was used as a process similar to the orthogonal...
-
MODELLING OF CUTTING BY MEANS OF FRACTURE MECHANICS
PublikacjaThe suitability of modern fracture mechanic theory was proved for the estimation of the cutting force and the cutting specific resistance. This paper shows modification of Ernst-Merchant theory and its application for determination some other properties of wood sample. This theory is acceptable for evaluation of shear yield stresses and shear plane angle. Sawing by gang saw machine was used as a process similar to the orthogonal...
-
Biobearings: where mechanics meets biology
PublikacjaStawy człowieka z punktu widzenia mechaniki są łożyskami ślizgowymi, jednak posiadają zupełnie inne właściwości niż łożyska przemysłowe. Artykuł omawia sposoby implementacji znanych zasad zachowania łożysk ślizgowych dla biołożysk z punktu widzenia materiałowego, uwzględniając te osiągnięcia w zakresie tribologii, biologii, chemii organicznej oraz inżynierii hodowli chrząstek, które są związane z łożyskami synowialnymi.
-
Soil mechanics and old buildings foundations
PublikacjaPraca dotyczy sposobów fundamentowania obiektów zabytkowych. Przeanalizowano historyczny rozwój sposobów posadowienia poczynając od starożytności, poprzez średniowiecze aż do czasów nowożytnych. Omówiono charakterystyczne dla kolejnych okresów historycznych rodzaje fundamentów. Przedstawiono przykłady dobrego i złego fundamentowania.
-
Correlation experiments in nonlinear quantum mechanics
PublikacjaPokazano w jaki sposób należy obliczać wieloczasowe i wielocząstkowe funkcje korelacyjne w nieliniowej mechanice kwantowej, aby zagwarantować lokalność formalizmu.
-
Tribological performance of PTFE-metal binary coatings in rolling/sliding contact
PublikacjaTribological performance of surface coatings with embedded PTFE reservoirs in rolling/sliding contact is reported. Using two different coating materials and two shapes and patterns of PTFE reservoirs test samples in the form of discs were prepared and tested in a four-ball contact configuration under loads corresponding to nominal contact pressure of 0.5 and 1.0 GPa. It was found that one coating, namely aluminium-bronze with embedded...
-
Constitutive Modelling of Knitted Abdominal Implants in Numerical Simulations of Repaired Hernia Mechanics
PublikacjaThe paper presents a numerical approach to describe mechanical behavior of anisotropic textile material, which is a selected abdominal prosthesis. Two constitutive nonlinear concepts are compared. In the first one the material is considered composed from two families of threads (dense net model) and in the second one the material is homogeneous but anisotropic (as proposed by Gassel, Ogden, Holzapfel). Parameters of both models...
-
Limits of enhanced of macro- and meso-scale continuum models for studying size effect in concrete under tension
PublikacjaThe paper investigates a mechanical quasi-static size effect in concrete during splitting tension at the macro- and meso-level. In experiments, five different diameters of cylindrical concrete specimens were tested. Twodimensional plane strain finite element (FE) simulations were carried out to reproduce the experimental size effect. The size effect in experiments by Carmona et al. was also simulated. Two enhanced continuum concrete...
-
Physico-Chemical Mechanics of Materials
Czasopisma -
MATHEMATICS AND MECHANICS OF SOLIDS
Czasopisma -
Wavelet transform-based approach to defect identification in railway carbon contact strips.
PublikacjaPantographs of electric rail vehicles are fitted with carbon contact strips, which slide along the contact wire of catenary to provide constant electrical contact. Contact strips are exposed to wear and damages. Using damaged contact strips significantly increases the risk of catenary rupture. Therefore, their technical condition has to be inspected frequently. In previous work a 3D laser scanning system was proposed for recording...
-
On topology optimization of large deformation contact-aided shape morphing compliant mechanisms
PublikacjaA topology optimization approach for designing large deformation contact-aided shape morphing compliant mechanisms is presented. Such mechanisms can be used in varying operating conditions. Design domains are described by regular hexagonal elements. Negative circular masks are employed to perform dual task, i.e., to decide material states of each element and also, to generate rigid contact surfaces. Each mask is characterized by...
-
INFLUENCE OF SURFACE CURVATURE ON SESSILE DROPLET CONTACT ANGLE OF NANOFLUIDS
PublikacjaThis paper deals with change in contact angle of droplets of three nanofluids, i.e. water-Al2O3, water-TiO2 and water-Cu. Nanoparticles were tested at the concentration of 0.01%, 0.1%, and 1% by weight. Although dispersants were not used to stabilize the suspension, the solutions tested exhibited satisfactory stability. Ultrasonic vibration was used in order to stabilise the dispersion of the nanoparticles. Experimental measurements...
-
A Generalized Framework Towards Structural Mechanics of Three-layered Composite Structures
PublikacjaThree-layered composite structures find a broad application. Increasingly, composites are being used whose layer thicknesses and material properties diverge strongly. In the perspective of structural mechanics, classical approaches to analysis fail at such extraordinary composites. Therefore, emphasis of the present approach is on arbitrary transverse shear rigidities and structural thicknesses of the individual layers. Therewith...
-
Perfect thermal contact of hyperbolic conduction semispaces with an interfacial heat source
PublikacjaThe problem of thermal contact between two bodies with a heat source at their interface presents great scientific and practical interest. On the time scale of a nanosecond or shorter, heat propagation should be considered in the form of thermal waves of finite speeds. This study investigated the thermal behaviour of hyperbolic conduction semispaces in perfect thermal contact subjected to the action of an interfacial heat source....
-
Contact Lens & Anterior Eye
Czasopisma -
Mathematical modelling of the overhead contact line for the purpose of diagnostics of pantographs
PublikacjaThe overhead contact line (OCL) is the most effective way for supplying railway electric vehicles. The increase of the speed of the vehicles increases power consumption and requires ensuring proper cooperation of pantographs with OCL. The paper describes the novel mathematical model of the OCL system and the simulation results. The primary objective is a more accurate analysis to increase the reliability of the evaluation of monitoring...
-
MECHANICS RESEARCH COMMUNICATIONS
Czasopisma -
Algorithm for Automatic Wear Estimation of Railway Contact Strips Based on 3D Scanning Results
PublikacjaElectric rail vehicles use current collection system which consists of overhead contact line and a current collector (pantograph) mounted on the roof of a vehicle. A pantograph is equipped with contact strips, which slide along the contact wire, ensuring steady electric contact. Contact strips are made of carbon layer, fixed to an aluminum carrier. The carbon layer wears down due to friction. Using overly worn contact strips increases...
-
Journal of Applied and Computational Mechanics
Czasopisma -
Dynamic Nanoimpedance Characterization of the Atomic Force Microscope Tip-Surface Contact
PublikacjaNanoimpedance measurements, using the dynamic impedance spectroscopy technique, were carried out during loading and unloading force of a probe on three kinds of materials of different resistivity. These materials were: gold, boron-doped diamond, and AISI 304 stainless steel. Changes of impedance spectra versus applied force were registered and differences in the tip-to-sample contact character on each material were revealed. To...
-
Wear estimation of current collector contact strips by analysis of a 3D scanning results
PublikacjaThe technical condition of current collector contact strips is very important when operational reliability of railway transportation is considered. The authors proposed a novel measurement system based on a 3D camera to register the shape and dimensions of the current collector contact strips surface. The system was installed above the railway track for tests in target ambient. During the trial operation a few dozen of contact...
-
3D Machine Vision System for Inspection of Contact Strips in Railway Vehicle Current Collectors
PublikacjaConstruction and technical condition of current collectors is crucial to reliability and safety of railway transportation. According to the Technical Specifications for Interoperability railway vehicles in the European Union should be equipped with carbon contact strips. Excessive wear or defects of contact strips degrade the capability of undisturbed power transmission, cause faster wear of contact wire, and can even result in...
-
Analysis of measurement uncertainty for contact-less method used to measure the position of catenary contact wire, performed with the use of Monte Carlo method
PublikacjaCurrently the majority of main railway lines in Europe are electrified, and electric trains have the biggest share in the entire amount of rail transport. Reliability of electrified railways is closely related to the issue of supplying traction vehicles with energy. The problems connected with diagnostics of energy consumption node, namely the contact line and the current collector, are therefore of fundamental importance for maintaining...
-
Advanced Mechanics of Marine Structures II W2021/22
Kursy OnlineLecture and Laboratory classes Advanced Mechanics of Marine Structures II W2021/22
-
Technical Mechanics
Kursy Online -
Approximation of Covariance Function with Application to Stochastic Mechanics.
PublikacjaW pracy przedstawiono koncepcję rozwinięć kanonicznych dla funkcji losowych oraz możliwość ich zastosowania w stochastycznej mechanice gruntów. Rozpatrzono rozkład widmowy, rozwinięcia Karhunena-Loevego oraz rozwinięcia ortogonalne zmodyfikowanymi wielomianami Hermite'a. Przeprowadzono analizę błędów dla zagadnienia warstwy gruntu o losowych parametrach sprężystych, uzyskano analityczne rozwiązanie systemu stochastycznego.
-
Innovative rehabilitation lifts – mechanics in medical devices
PublikacjaMechanical devices are now widely used in physiotherapy and other rehabilitation processes. Particular importance is attached to devices enabling easy and effective transport of disabled people. The article presents innovative designs of rehabilitation lifts offered by the Polish manufacturer of lifts and medical accessories, LeviCare company. Moreover, the main assumptions of the research and development project implemented by...
-
SESSILE DROPLET CONTACT ANGLE OF WATER-Al2O3, WATER-TiO2 AND WATER-Cu NANOFLUIDS
PublikacjaThe goal of the present work was the experimental determination of the contact angle of droplets of three nanofluids on various substrates. Of particular interest was effect of nanoparticle concentration on droplet contact angle.
-
The Creation of an Antimicrobial Coating on Contact Lenses by The Use of Nanocopper
PublikacjaThe aim of the research was to creation an antimicrobial coating on contact lens and examine the ability of copper nanoparticles to decrease microbial adhesion and prevent the growth of bacteria. The creation was based on the immersion method in solution with dispersed nanoparticles of copper at concentration 200 pm. There were evaluated follows factors: time of immersion and base to dispersed nanoparticles. Three solutions: ethyl...
-
Sessile droplet contact angle of water–Al2O3, water–TiO2 and water–Cu nanofluids
PublikacjaThis work presents measurements of the contact angle of sessile droplets for three nanofluids, i.e. water–Al2O3, water–TiO2 and water–Cu. The plates made of glass, anodized aluminium and stainless steel of different roughness served as substrates. Ultrasonic vibration was used for 30–60 min in order to stabilise the dispersion of the nanoparticles. Nanoparticles were tested at the concentration of 0.01%, 0.1%, and 1% by weight....
-
The Effect of Flexible Pavement Mechanics on the Accuracy of Axle Load Sensors in Vehicle Weigh-in-Motion Systems
PublikacjaWeigh-in-Motion systems are tools to prevent road pavements from the adverse phenomena of vehicle overloading. However, the effectiveness of these systems can be significantly increased by improving weighing accuracy, which is now insufficient for direct enforcement of overloaded vehicles. Field tests show that the accuracy of Weigh-in-Motion axle load sensors installed in the flexible (asphalt) pavements depends on pavement temperature...
-
ARCHIVES OF MECHANICS
Czasopisma -
CONTINUUM Lifelong Learning in Neurology
Czasopisma -
Towards Understanding of Mechanics of Hernia Managed by Synthetic Mesh in Laparoscopic Operation: A Single Case Study
PublikacjaIn this paper a research towards understanding of mechanics of ventral hernia operated with the use of Physiomesh Open image in new window implant and SecureStrap Open image in new window staples is described. Experimental and numerical studies are conducted for that purpose. Experimental works cover uni-axial tension tests of the implant samples and of the implant-staples-tissue system. Also experiments on implant-staples-tissue...
-
Application of infrared thermoography to non-contact testing of varistors
PublikacjaTesting of varistors using thermography was carried out in order to assess their protective properties against possible overvoltage phenomena in the form of high-level voltage surges. An advantage of the thermography technique is non-contact temperature measurement. It was proposed to assess the properties of varistors workingin electronic devices as protective elements, on the basis of estimating temperature increments on varist...
-
Practical Applications for Single Pill Combinations in the Cardiovascular Continuum
Publikacja -
Implementation of continuum damage in elasto-viscoplastic constitutive equations
PublikacjaW pracy opisano podstawowy wariant modelu Chaboche, oraz założenia i implementacje kontynualnego modelu zniszczenia do komercyjnego programu MES. W pracy zaprazentowano dwa podejścia zobrazowane na przykładach obliczeń numerycznych.
-
Implementation and Validation of Multisinusoidal, Fast Impedance Measurements in Atomic Force Microscope Contact Mode.
PublikacjaThis study presents a novel approach to impedance measurements. The methodology discussed is limited to contact in the sample-probe system under ambient conditions without the presence of electrolyte. Comparison with results of direct and alternating current measurements for well-defined metallic surfaces are made. In spite of idealization related to the type of contact examined, the proposed technique provides an improvement of...
-
Influence of concentration on contact angle of water-Cu nanofluid on glass substrate
PublikacjaIn the paper the results of an experimental investigation of influence of nanoparticle concentration on contact angle of water-Cu nanofluid on glass substrate have been presented. Nanoparticles were tested at the concentration of 0.01%, 0.1%, and 1% by weight. In the present study copper was applied as nanoparticle while distilled, deionized water was used as a base fluid. The mean diameter of nanoparticle is estimated to be 50...