Search results for: BOUNDARY SURFACE
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Analytical Steady-State Model of the Pipeline Flow Process
PublicationThe paper addresses the issue of modeling the flow process in transmission pipelines. A base model used for numerical simulation is introduced. Under certain assumptions concerning steady state analysis, the differential equations describing the process are solved analytically for two cases: zero and nonzero inclination angle α. These equations describe a constant flow rate and a corresponding distribution of the pressure along...
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Galvanostatic impedance measurements for the efficient adsorption isotherm construction in corrosion inhibitor studies
PublicationWe present an approach towards an accurate and time-efficient adsorption isotherm determination to evaluate the corrosion inhibitor interaction in electrolytic environments. The approach is based on dynamic impedance spectroscopy measurements in galvanostatic mode (g-DEIS). The studied corrosion inhibitor is continuously injected between the secondary cell and the corrosion cell. The efficiency corresponding to instantaneous inhibitor...
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Influence of the air phase on water flow in dikes
PublicationNumerical models are often used to describe flow and deformation processes occurring in dikes during flood events. Modeling of such phenomena is a challenging task, due to the complexity of the system, consisting of three material phases: soil skeleton, pore water and pore air. Additional difficulties are transient loading caused by variable in time water levels, heterogeneity of the soil or air...
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Selected problems of decision making modelling in power engineering
PublicationThe paper presents the selected problems of decision making modelling in power engineering specially investment risk evaluation methods. The proposed model can be used in the range programming the development and investing process in power engineering. Decision making problems in power engineering and the evaluation of investment effectiveness in particular are closely related to modelling which relatively accurately reflects...
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Modelling tunnelling-induced deformation in stiff soils with a hyperelastic–plastic anisotropic model
PublicationIn this paper, the tunnelling-induced deformation in anisotropic stiff soils is analysed using FE modelling. The influence of material description is investigated rather than an advanced simulation of the tunnelling method. A new hyperelastic– plastic model is proposed to describe the anisotropic mechanical behaviour of stiff highly overconsolidated soil. This model can reproduce the superposition of variable stress-induced anisotropy...
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Long-term hindcast simulation of sea ice in the Baltic Sea
Open Research DataThe data set contains the results of numerical modeling of sea ice over a period of 50 years (1958-2007) in the Baltic Sea. A long-term hindcast simulation was performed using a three-dimensional hydrodynamic model PM3D (Kowalewski and Kowalewska-Kalkowska, 2017), a new version of the M3D model (Kowalewski, 1997). A numerical dynamic-thermodynamic model...
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An asymmetrical λ-foot of condensing steam flow in the IMP PAN nozzle
PublicationIn the present paper we have focused on the precise prediction of the spontaneous condensation phenomena in wet steam flow. Novelty of our approach lies on modelling both the moment of initiation of a phase transition, as well as the moment of its reverse progress - called here re-vaporization of the condensate phase. The practical issue is to elaborate of a model of spontaneous condensation/vaporization of water steam flow...
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Comparison of strain results at a laser weld notch obtained by numerical calculations and experimental measurements
PublicationIn the development of ship structures applying new materials and it’s purposeful placement play an important role. During the last years, especially in a construction of ro-ro type vessels, the usage of novel sandwich structures in cargo decks is profitable. Steel sandwich panel is an innovative solution which at a todays state of development can be used for the construction of any members not taking part in a global bending of...
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Modular Approach for Modelling Warming Up Process in Water Installations with Flow-Regulating Elements
PublicationThe paper presents a new method for modelling the warming up process of a water system with elements regulating the flow in a stochastic manner. The paper presents the basic equations describing the work of typical elements which the water installation is composed of. In the proposed method, a new computational algorithm was used in the form of an iterative procedure enabling the use of boundary conditions that can be stochastically...
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Trailing-Edge Separation Control of a NACA 0015 Airfoil Using Dielectric-Barrier-Discharge Plasma Actuators
PublicationThis paper presents a part of the works conducted in the Plasmaero European project (task 3.1), where the trailing-edge flow separation of a NACA 0015 airfoil has been controlled using four different dielectric barrier discharge (DBD) actuator types at three institutions across Europe. The results show that it is possible to enhance the aerodynamic performance of aircraft at speeds up to 40 m/s. Dielectric-barrier-discharge vortex...
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Investigations On Water Circulation in Animal Sea-Water Basins – On the Example of Seals′ Breeding Pools
PublicationThis paper presents general comments concerning investigations on water circulation in animal breeding pools containing sea water. As an example are given results of computer simulation of water circulation in seals’ breeding pools situated in Marine Station at Hel, belonging to Oceanographic Institute, Gdansk University. A mathematical model of three main pools was prepared with taking into account their inflow and outflow water...
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Influence of addition of carbon nanotubes on rheological properties of selected liquid lubricants - a computer simulation study
PublicationThis work is motivated by the improvement of anti-friction properties of lubricants by addition of CNTs proved experimentally in literature. In particular, a methodology is developed to compute the shear viscosity of liquid lubricants (Propylene Glycol) based on Molecular Dynamics simulation. Non-Equilibrium molecular dynamics (NEMD) approach is used with a reactive force field ReaxFF implemented in LAMMPS. The simulations are...
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A study on diagnosing both isotropic and orthotropic, intentionally damaged laminates
PublicationBeing the most detrimental mode in laminated structures, delamination initially degrades local structural strength, and lastly causes global structural failure, thus necessitating delamination identification at its incipient stages. For identification purposes, a comprehensive numerical and experimental study on delamination within both the laminated isotropic acrylic-glass and orthotropic epoxyglass plates is presented. As the...
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Deformation of an elastic second gradient spherical body under equatorial line density of dead forces
PublicationWe consider deformations of an elastic body having initially a spherical shape. Assumed deformation energy depends on the first and second gradient of displacements. We apply an equatorial line density of dead loads, that are forces per unit line length directed in radial direction and applied along the equator of the sphere. We restrict ourselves our analysis to the case of linearized second strain gradient isotropic elasticity...
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Influence of soil anisotropic stiffness on the deformation induced by an open pit excavation.
PublicationIn this paper, the problem of deformation induced by an open pit excavation in anisotropic stiff soils is analysed by FE modelling. The presented research is focused on the influence of material model with anisotropic stiffness on the accuracy of deformation predictions as compared with the field measurements. A new hyperelastic-plastic model is applied to simulate anisotropic mechanical behaviour of stiff soils. It is capable...
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Dynamic modeling of non-cylindrical curved viscoelastic single-walled carbon nanotubes based on the second gradient theory
PublicationThis paper is devoted to the theoretical study of the dynamic response of non-cylindrical curved viscoelastic single-walled carbon nanotubes (SWCNTs). The curved nanotubes are largely used in many engineering applications, but it is challenging in understanding mechanically the dynamic response of these curved SWCNTs when considering the influences of the material viscosity. The viscoelastic damping effect on the dynamic response...
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Persistences: analysis of the image of Gdańsk and its cultural identity through survey processes and digital architectural representation
PublicationThe aim of the research was to analyse the historical legacy/heritage of the city of Gdańsk in order to characterise the narrative tools which can be used to promote the cultural identity of the urban landscape. The main focus was on the city's defence system - a cultural route that is spatially limited to a relatively small area, but temporally spanning almost a millennium. The fortifications demarcate a spatial boundary, limiting...
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Fault detection in electronic circuits using test buses
PublicationA survey of test buses designed for diagnostics of digital and analog electronic circuits is presented: the IEEE 1149.1 bus for digital circuits, the IEEE 1149.4 bus for mixed-signal and the IEEE 1149.6 bus for AC coupled complex digital circuits. Each bus is presented with its structure, solution of key elements, particularly boundary registers and a set of test instructions. Diagnosis with the use of the described buses is...
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Experimental investigation of heat transfer enhancement in straight and U-bend double-pipe heat exchanger with wire insert
PublicationIn this paper, the possibility of heat transfer enhancement in the U-bend exchanger was presented. Experimental research has been carried out for four individual heat exchanger constructions i.e. plain tube in tube, turbulized tube in tube, plain U-bend and U-bend with turbulator. Also, heat transfer experiments for various boundary conditions were performed to obtain reference values. In case of U-bend exchanger with and without...
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Updating the Coupling Algorithm between HYDRUS and MODFLOW in the HYDRUS Package for MODFLOW
PublicationThe HYDRUS-based flow package for MODFLOW (the HPM or the HYDRUS package) is an existing unsaturated zone flow package for MODFLOW. In MODFLOW with the HPM, the groundwater modeling domain is discretized into regular grids that can be combined into multiple zones based on similarities in soil hydrology, topographical characteristics, and the depth to the groundwater. Each of these zones is assigned one unsaturated soil profile...
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Cavity-expansion approximation for projectile impact and penetration into sand
PublicationA one-dimensional problem of a spherical cavity expanding at a constant velocity from zero initial radius in an infinite granular medium, which has the first-kind self-similar solution, is considered. We are solving this dynamic spherical cavity-expansion problem to model rigid spheres penetrating into a granular media. Elastic–plastic deformation of the granular media is described in a barotropic approximation, using the high-pressure...
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Numerical Model of Femur Part
PublicationThe aim of the study is to create a new more accurate method of femur part modelling by using the finite element method. According to this new method, a femur part is treated as a complex structure composed of trabecular bone (internal part) and cortical bone (external part). The internal part is modelled as a scaffold, thus the external part is modelled as a coat (i.e. covering). Applying the programme ABAQUS, there were created...
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Theoretical examination of the fracture behavior of BC3 polycrystalline nanosheets: Effect of crack size and temperature
Publication2D carbon graphene nanostructures are elements of advanced materials and systems. This theoretical survey provides explanation to the mechanical and fracture behavior of mono- and polycrystalline BC3 nanosheets (denoted as MC- and PCBC3NS, respectively) as a function of temperature and the type of crack defects. The mechanical performance of PCBC3NS at elevated temperatures was monitored varying the number of grain boundaries (the...
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Electrical properties of A-site Ca-doped LaNb1-xAsxO4-δ ceramics
PublicationThe electrical properties of A-site Ca-doped LaNbO4 with the addition of As in the B-site, have been investigated. Total, grain- and specific grain boundary electric conductivities in different oxygen partial pressure, and water vapour partial pressure were determined. Additional conductivity measurements were performed in nitrogen, to suppress the possible p-type conductivity, focusing on protonic conductivity. The maximum measured...
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Coupled nonlinear Schrödinger equations in optic fibers theory
PublicationIn this paper a detailed derivation and numerical solutions of CoupledNonlinear Schr¨odinger Equations for pulses of polarized electromagnetic wavesin cylindrical fibers has been reviewed. Our recent work has been compared withsome previous ones and the advantage of our new approach over other methods hasbeen assessed. The novelty of our approach lies is an attempt to proceed withoutloss of information within the frame of basic...
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Isolation of the relative decrease in magnetic permeability contribution to reluctance of an open magnetic circuit based on stray field measurements
PublicationThe goal of the study was to evaluate a relative decrease in magnetic permeability in open magnetic circuits based on stray magnetic field measurements. The boundary element method was used to simulate magnetic circuits with variable geometry and variable magnetic permeability. The simulated magnetic circuits were rectangular or bone-shaped flat samples. Reluctance was increased in the middle of the samples resulting in leakage...
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Application of shifted Chebyshev polynomial-based Rayleigh–Ritz method and Navier’s technique for vibration analysis of a functionally graded porous beam embedded in Kerr foundation
PublicationPresent study is dealt with the applicability of shifted Chebyshev polynomial based Rayleigh-Ritz method and Navier’s technique on free vibration of Functionally Graded (FG) beam with uniformly distributed porosity along the thickness of the beam. The material properties such as Young’s modulus, mass density, and Poisson’s ratio are also considered to vary along the thickness of the FG beam as per the power-law exponent model....
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Corrosivity of environment and the current state of the steel elements at the former Auschwitz concentration camp
PublicationThe objective of this study was to assess corrosivity of the atmospheric environment in the former Auschwitz I and Auschwitz II-Birkenau concentration and extermination camp, and to identify the protective properties of existing corrosion products in order to estimate the actual corrosion rate of original steel elements located there. The current atmospheric corrosivity of the former Auschwitz camp, specified during one year of exposure...
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Biomechanics of Lumbar Spine Injury in Road Barrier Collision–Finite Element Study
PublicationLiterature and field data from CIREN database have shown that lumbar spine injuries occur during car crashes. There are multiple hypotheses regarding how they occur; however, there is no biomechanical explanation for these injuries during collisions with road safety barriers (RSBs). Therefore, the objective of this study was to investigate the mechanics of vertebral fractures during car collisions with concrete RSBs. The finite...
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On the generalized model of shell structures with functional cross-sections
PublicationIn the present study, a single general formulation has been presented for the analysis of various shell-shaped structures. The proposed model is comprehensive and a variety of theories can be used based on it. The cross-section of the shell structure can be arbitrarily analyzed with the presented equations. In other words, various types of shell structures, including cylindrical, conical, spherical, elliptical, hyperbolic, parabolic,...
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Structure-property relationships in peroxide-assisted blends of poly(ε-caprolactone) and poly(3-hydroxybutyrate)
PublicationPoly(ε-caprolactone) and poly(3-hydroxybutyrate) (PCL/PHB) blends in two weight ratios (75/25 and 50/50) were reactively compatibilized in the presence of di-(2-tert-butyl-peroxyisopropyl)-benzene and dicumyl peroxide as free radical initiators. Rheological, mechanical, thermal properties and morphological features, as well as the chemical structure of PCL/PHB blends were investigated. It was found that regardless of PCL/PHB blend...
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Preparation and characterization of natural rubber composites highly filled with brewers' spent grain/ground tire rubber hybrid reinforcement
PublicationBrewers' spent grain (BSG) and ground tire rubber (GTR) were applied as low-cost hybrid reinforcement natural rubber (NR). The impact of BSG/GTR ratio (in range: 100/0, 75/25, 50/50, 25/75 and 0/100 phr) on processing and performance properties of highly filled natural rubber composites was evaluated by oscillating disc rheometer, Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy,...
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A new hyperbolic-polynomial higher-order elasticity theory for mechanics of thick FGM beams with imperfection in the material composition
PublicationA drawback to the material composition of thick functionally graded materials (FGM) beams is checked out in this research in conjunction with a novel hyperbolic‐polynomial higher‐order elasticity beam theory (HPET). The proposed beam model consists of a novel shape function for the distribution of shear stress deformation in the transverse coordinate. The beam theory also incorporates the stretching effect to present an indirect...
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Comparative 3D DEM simulations of sand–structure interfaces with similarly shaped clumps versus spheres with contact moments.
PublicationThree-dimensional simulations of a monotonic quasi-static interface behaviour between initially dense cohesionless sand and a rigid wall of different roughness during tests in a parallelly guided direct shear test under constant normal stress are presented. Numerical modelling was carried out by the discrete element method (DEM) using clumps in the form of convex non-symmetric irregularly shaped grains. The clumps had an aspect...
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Database of the convergence analysis results of the nonstandard approximation of the generalized Burgers–Huxley equation for the solution bounded within [0,1].
Open Research DataThe presented dataset is a result of the convergence analysis of the Mickens-type, nonlinear, finite-difference discretization of a generalized Burgers–Huxley partial differential equation.
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Database of the convergence analysis results of the nonstandard approximation of the generalized Burgers–Huxley equation for the solution bounded within [0, γ^(1/p)].
Open Research DataPresented dataset is a result of the convergence analysis of the Mickens-type, nonlinear, finite-difference discretization of a generalized Burgers–Huxley partial differential equation. The generalized Burgers–Huxley equation is a diffusive partial differential equation with nonlinear advection and diffusion. The boundary problem for this equation possesses...
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Combined numerical and experimental approach to determine numerical model of abdominal scaffold
PublicationA proper junction of the prosthesis and the abdominal wall is important in successful hernia repair. The number of tacks should be balanced to assure appropriate mesh fixation and not to induce post-operative pain. Numerical simulations help to find this balance. The study is aimed at creating a proper numerical model of a knitted surgical mesh subjected to boundary conditions and load occurring in the abdominal cavity. Continuous,...
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Degradation of a nano-cutting tool: an MD simulation
PublicationW pracy przedstawiono wyniki symulacji wielokrotnego oddziaływania realistycznie ukształtowanego ostrza tnącego z modelowym, nieskończenie twardym ziarnem, przy zastosowaniu metody dynamiki molekularnej. Ostrze składało się z kilkuset tysięcy atomów metalu fcc, traktowanego za pomocą potencjału Suttona-Chena, przesuwane było ze stałą prędkością 20 m/s. Obserwowane deformacje plastyczne pojawiające się na skutek kontaktu ostrza...
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Historical carpentry corner log joints—Numerical analysis within stochastic framework
PublicationThe paper presents the results of numerical analysis performed on historical, traditional carpentry corner logjoints of two basic topologies: the short-corner dovetail connection and the saddle notch connection. These types of carpentry joints are commonly used in currently preserved objects of wooden architecture. All connections have been modelled in pinewood, which has been defined in the Finite Element software MSC.Marc/Mentat...
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Refinement of the Hardening Soil model within the small strain range
PublicationThe popularity of the elasto-plastic Hardening Soil (HS) model is based on simple parameter identification from standard testing and empirical formulas. The HS model is implemented in many commercial FE codes designed to analyse geotechnical problems. In its basic version, the stress–strain behaviour within the elastic range is subject to the hypoelastic power law, which assures the barotropy of the elastic stiffness. However,...
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Implementation of Non-Probabilistic Methods for Stability Analysis of Nonlocal Beam with Structural Uncertainties
PublicationIn this study, a non-probabilistic approach based Navier’s Method (NM) and Galerkin Weighted Residual Method (GWRM) in term of double parametric form has been proposed to investigate the buckling behavior of Euler-Bernoulli nonlocal beam under the framework of the Eringen's nonlocal elasticity theory, considering the structural parameters as imprecise or uncertain. The uncertainties in Young’s modulus and diameter of the beam are...
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Verification of the method of reconstructing convective velocity fields on the basis of temperature fields in vertical, differential and equally heated, open and closed channels
PublicationThis paper describes a method of reconstructing velocity fields, i.e. a numerical reconstruction procedure (NRP) that involves the numerical processing of experimentally measured temperature distributions in free convection heat transfer. The NRP consists in solving only the continuity and Navier–Stokes equations with an additional source term. This term is proportional to a known temperature (e.g. from a thermal imaging camera)...
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DL_MG: A Parallel Multigrid Poisson and Poisson–Boltzmann Solver for Electronic Structure Calculations in Vacuum and Solution
PublicationThe solution of the Poisson equation is a crucial step in electronic structure calculations, yielding the electrostatic potential -- a key component of the quantum mechanical Hamiltonian. In recent decades, theoretical advances and increases in computer performance have made it possible to simulate the electronic structure of extended systems in complex environments. This requires the solution of more complicated variants of the...
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Buckling analysis of piezo-magnetoelectric nanoplates in hygrothermal environment based on a novel one variable plate theory combining with higher-order nonlocal strain gradient theory
PublicationIn the present investigation, a new first-order shear deformation theory (OVFSDT) on the basis of the in-plane stability of the piezo-magnetoelectric composite nanoplate (PMEN) has been developed, and its precision has been evaluated. The OVFSDT has many advantages compared to the conventional first-order shear deformation theory (FSDT) such as needless of shear correction factors, containing less number of unknowns than the existing...
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Fluid structure interaction study of non-Newtonian Casson fluid in a bifurcated channel having stenosis with elastic walls
PublicationFluid–structure interaction (FSI) gained a huge attention of scientists and researchers due to its applications in biomedical and mechanical engineering. One of the most important applications of FSI is to study the elastic wall behavior of stenotic arteries. Blood is the suspension of various cells characterized by shear thinning, yield stress, and viscoelastic qualities that can be assessed by using non-Newtonian models. In this...
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The effective elastic properties of human trabecular bone may be approximated using micro-finite element analyses of embedded volume elements.
PublicationBoundary conditions (BCs) and sample size affect the measured elastic properties of cancellous bone. Samples too small to be representative appear stiffer under kinematic uniform BCs (KUBCs) than under periodicity-compatible mixed uniform BCs (PMUBCs). To avoid those effects, we propose to determine the effective properties of trabecular bone using an embedded configuration. Cubic samples of various sizes (2.63, 5.29, 7.96, 10.58...
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Transport of Particles in Intestinal Mucus under Simulated Infant and Adult Physiological Conditions: Impact of Mucus Structure and Extracellular DNA
PublicationThe final boundary between digested food and the cells that take up nutrients in the small intestine is a protective layer of mucus. In this work, the microstructural organization and permeability of the intestinal mucus have been determined under conditions simulating those of infant and adult human small intestines. As a model, we used the mucus from the proximal (jejunal) small intestines of piglets and adult pigs. Confocal...
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HYGRO-MAGNETIC VIBRATION OF THE SINGLE-WALLED CARBON NANOTUBE WITH NONLINEAR TEMPERATURE DISTRIBUTION BASED ON A MODIFIED BEAM THEORY AND NONLOCAL STRAIN GRADIENT MODEL
PublicationIn this study, vibration analysis of single-walled carbon nanotube (SWCNT) has been carried out by using a refined beam theory, namely one variable shear deformation beam theory. This approach has one variable lesser than a contractual shear deformation theory such as first-order shear deformation theory (FSDT) and acts like classical beam approach but with considering shear deformations. The SWCNT has been placed in an axial or...
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Experimental and computational study on mechanical behaviour of carpentry corner log joints
PublicationThis work concerns experimental and numerical research on carpentry joints used in historic wooden buildings in southeastern Poland and western Ukraine. These structures are mainly sacred buildings, and the types of corner log joints characteristic of this region are primarily saddle-notch and dovetail joints; thus, these two types of joints were analysed in this study. The modelling of historic timber structures is a complex...
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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...