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MODELLING OF THE VISCOSITY EFFECT OF HEAVE PLATES FOR FLOATING WIND TURBINES BY HYDRODYNAMIC COEFFICIENTS
PublikacjaOne of the methods of modelling the movement of floating wind turbines is the use of the diffraction method. However, this method does not take into account the influence of viscosity; therefore, in many cases, it needs to be extended with a matrix of appropriate coefficients. The effect of viscosity causes both the added mass coefficient and the damping coefficient to increase. The determined coefficients were entered into the...
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Estimation of the Regenerative Braking Process Efficiency in Electric Vehicles
PublikacjaIn electric and hybrid vehicles, it is possible to recover energy from the braking process and reuse it to drive the vehicle using the batteries installed on-board. In the conditions of city traffic, the energy dissipated in the braking process constitutes a very large share of the total resistance to vehicle motion. Efficient use of the energy from the braking process enables a significant reduction of fuel and electricity consumption...
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Obliczeniowa ocena zdeformowanego węzła dźwignicy
PublikacjaW pracy przedstawiono wybrane problemy obliczeń wytrzymałościowych węzła ładowarki statkowej, który uległ uszkodzeniu. Przeprowadzono szereg analiz numerycznych, które miały na celu zidentyfikowanie przyczyn i warunków powstania zaobserwowanej formy deformacji. Następnie oceniono stan bezpieczeństwa węzła i zaproponowano najmniej złożone sposób jego naprawy oraz modernizacji mającej na celu poprawę bezpieczeństwa pracy. Całość...
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Examples of a use of the optimal control at energy performance index in mechatronic approach
PublikacjaW pracy zaprezentowano przykłady zastosowania sterowania optymalnego przy energetycznym wskaźniku jakości w rozwiązaniach mechatronicznych. Rozważano układy mechaniczne modelowane dyskretnie. Metody sterowania optymalnego znalazły zastosowanie w robotyce (kołowe roboty mobilne jako układy silnie nieliniowe) oraz obróbce szybkościowej przedmiotów podatnych frezem kulistym.
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Wady powierzchniowe ceramicznych elementów tocznych = Surface cracks of ceramic rolling elements
PublikacjaMateriały ceramiczne posiadają kombinację optymalnych własności, które są niezbędne w zastosowaniach na wysoko obciążone elementy maszyn. Podstawowym problemem związanym z wytrzymałością zmęczeniową materiałów ceramicznych są wszelkiego rodzaju wady powierzchniowe będące efektem procesu wytwarzania lub wynikające z defektów struktury materiału ceramicznego. W artykule przedstawiono badania doświadczalne dwutlenku cyrkonu ze sztucznie...
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Municipal Waste Management in Poland Compared to Other European Union Countries
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Analysis of the Water Footprint of Central and Eastern Europe Countries
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Experiments and Analysis of the Limit Stresses of a Magnetorheological Fluid
PublikacjaPaper presents the results of a rheological test of a commercial magnetorheological (MR) fluid (MRF-132DG). The researchincludes the problem of measuring and interpreting limit stresses under conditions close to the magnetic saturation of the fluid. Fourdifferent limit stresses were determined, two related to the yield point and two related to the flow point. Methods for determining limitstresses, especially due to excitation...
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The analysis of soil resistance during screw displacement pile installation
PublikacjaThe analysis of soil resistances during screw displacement pile installation based on model and field tests. The investigations were carried out as a part of research project, financed by the Polish Ministry of Science and Higher Education. A proposal of empirical method for prediction of rotation resistance (torque) during screw auger penetration in non-cohesive subsoil based on CPT result.
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NUMERICAL SIMULATION OF CRATER CREATING PROCESS IN DYNAMIC REPLACEMENT METHOD BY SMOOTH PARTICLE HYDRODYNAMICS
PublikacjaA theoretical base of SPH method, including the governing equations, discussion of importance of the smoothing function length, contact formulation, boundary treatment and finally utilization in hydrocode simulations are presented. An application of SPH to a real case of large penetrations (crater creating) into the soil caused by falling mass in Dynamic Replacement Method is discussed. An influence of particles spacing on method...
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Numerical estimation of the pile toe and shaft unit resistances during the installation process in sands
PublikacjaNumerical simulations of a pile jacking were carried out. A Coupled Eulerian–Lagrangian (CEL) formulation was used to treat with large deformation problems. An Abaqus, a commercial Finite Element Method software suit, was used as a computing environment. The Mohr–Coulomb constitutive model was applied and the Coulomb model of friction was used to describe pile-soil interaction. Calculations were made for three different pile diameters....
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Bearing capacity of the working platform with kinematic method
PublikacjaBearing capacity of the working platform for heavy tracks was analysed using Distinct Layout Optimization (DLO) method. The platform layer constructed from cohesionless soils is resting on weak cohesive subgrade. Different thickness of the platform, its effective angle of internal friction and undrained shear strength of the soft soil were taken into consideration. Kinematic method permits different failure mechanisms to be analyzed....
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Particle Shape Effect on Macroscopic Behaviour of Underground Structures: Numerical and Experimental Study
PublikacjaAbstract: The mechanical performance of underground flexible structures such as buried pipes or culverts made of plastics depend not only on the properties of the structure, but also on the material surrounding it. Flexible drains can deflect by 30% with the joints staying tight, or even invert. Large deformations of the structure are difficult to model in the framework of Finite Element Method, but straightforward in Discrete...
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MECHANICAL PROPERTIES OF BOTTOM ASH – DREDGED MATERIAL MIXTURES IN LABORATORY TESTS
PublikacjaBottom ash from EC Gdańsk and dredged material taken from the mouth of The Vistula were mixed to form an engineering material used for dike construction. Mixtures with different bottom ash content were tested in laboratory to determine its basic physical and mechanical properties. The optimum bottom ash–dredged material mixture, built in the corps of the test dike, contains 70% of ash. The optimum bottom ash content in the mixture...
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INFLUENCE OF TIME ON THE BEARING CAPACITY OF PRECAST PILES
PublikacjaOne of the most popular types of foundations in layered subsoil with very differentiated soil shear strengths are precast piles. One of the reasons is a fact that we can well control the driving process during the installation of these piles. The principles of the assessment of bearing capacity and settlements of the piles given by Eurocode 7, concentrate on two main methods, i.e. Static Pile Load Tests (SPLT) and Dynamic Driving...
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Deep compaction control of sandy soils
PublikacjaVibroflotation, vibratory compaction, micro-blasting or heavy tamping are typical improvement methods for the cohesionless deposits of high thickness. The complex mechanism of deep soil compaction is related to void ratio decrease with grain rearrangements, lateral stress increase, prestressing effect of certain number of load cycles, water pressure dissipation, aging and other effects. Calibration chamber based interpretation...
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Relation between benchmark displacement velocity and seismic activity caused by underground longwall exploitation
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Antimicrobial and antifungal activities of the extracts and essential oils of Bidens tripartita.
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Investigation of the reliability of local strain analysis by means of the triangle modelling
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Uncertainties of geodetic velocities from permanent GPS observations:The Sudeten case study
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Multi split functional model of geodetic observations in deformation analyses of the Olsztyn castle
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Configuration of the reference stations as the element of national reference frame reliability
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Determination of vertical indicators of ground deformation in the Old and Main City of Gdansk area by applying unconventional method of robust estimation
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Pile Model Tests Using Strain Gauge Technology
PublikacjaOrdinary pile bearing capacity tests are usually carried out to determine the relationship between load and displacement of pile head. The measurement system required in such tests consists of force transducer and three or four displacement gauges. The whole system is installed at the pile head above the ground level. This approach, however, does not give us complete information about the pile-soil interaction. We can only determine...
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Reduction of Derivative pipeline effort in water turbine
PublikacjaThe paper presents an approach to evaluate and reduce the effort of the derivative pipeline in a water turbine of a hydrostatic power station in its vulnerable spots. Potential places of the biggest effort of the structure, as well as the coefficient of displacement and safety factor related to them were identified using FEM numerical method. Pipeline reinforcement was designed and made based on FEM analysis. Original technology...
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Comparative model tests of SDP and CFA pile groups in non-cohesive soil
PublikacjaThe research topic relates to the subject of deep foundations supported on continuous flight auger (CFA) piles and screw displacement piles (SDP). The authors have decided to conduct model tests of foundations supported on the group of piles mentioned above and also the tests of the same piles working alone. The tests are ongoing in Geotechnical Laboratory of Gdańsk University of Technology. The description of test procedure, interpretation...
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Mobile application technology in levelling
PublikacjaThe topic of this article is the use of mobile application technology in geodetic measurements with an emphasis on levelling. Reference points were registered as data from levelling benchmarks, performed with a traditional dumpy level. The created application allowed the recording of measurements on location, sending them to a remote server for processing and preparing a report to be saved in a database. The project was to decrease...
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Investigation of environmental influences to the precise GNNS solutions
PublikacjaThe results presented in this paper concern investigation of environmental influences to GNNS coordinates on the example of ASG-EUPOS network. The problem of the impact of environmental effects is crucial for observing gravity. Satellite systems are not as susceptible to changes in local hydrology or atmospheric effects, although significant influences are clearly visible in the change of coordinates. The authors analyzed daily...
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Application of short-time GNSS solution geodynamical studies
PublikacjaThe paper presents the results of research related to the application of GNSS solutions in short observational periods in geodynamical investigations. Authors used the 3-hour solution appointed from hour-long interval of about 30 chosen stations on mountainous terrains from over 100 which were worked out. The main aim was to check the correctness of such solutions by the comparison with the daily ones. Some outliers in East component...
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MONITORING OF PERMANENT GPS STATIONS AT THE SUDETY MOUNTAINS
PublikacjaThe aim of this paper is to show time-dependent baseline variation between GPS stations situated in South-East Poland. This study was based on daily data analysis of selected GPS stations: WROC, GOPE, MOPI, KRAW and KATO. The start date of the analysis is linked at every station with the beginning of its operation and the closing date of the operation is in 2006. The multiresolution signal decomposition method has been used to...
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Investigation on stability of mountainous EUPOS sites’ coordinates
PublikacjaThe paper concerns analysis of solutions obtained during common processing of data from GNSS permanent stations situated on mountainous terrain: the Western Carpathians, the Sudetes Mountains and adjacent areas. As the outcome daily and weekly solutions (ellipsoidal coordinates) of forty Polish, Czech, Slovak, Ukrainian and German sites were obtained. Weekly solutions were used to determine velocity field and vertical movements,...
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Annual signals observed in regional GPS networks
PublikacjaAbstract: This paper describes analyses concerning annual signals in GPS-derived coordinates. The data was processed in the Military University of Technology Local Analysis Centre with Bernese 5.0 software. We used observations from 129 permanent GPS stations which belong to the Polish Active Geodetic Network (ASG-EUPOS), for the period of GPS weeks 1465-1729, corresponding to about 5 years. The annual signals have been estimated...
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Frequency and phase analysis of daily reprocessed solutions from selected EPN stations relating to geological phenomena,
PublikacjaThe main assumption of this research was to check and verify the behaviour of a few EPN (European Permanent Network) stations on both sides of the Teisseyre-Tornquist zone (T-T zone), which is located on Polish territory and crosses Poland almost in half. The selected EPN stations’ time series were a subject of frequency and phase analysis. The main purpose of the research was to verify if there is any correspondence between stations...
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GNSS reference solution for permanent station stability monitoring and geodynamical investigations: the ASG-EUPOS case study.
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MESOSCALE FUNCTIONS OF GPS SLANT DELAY
PublikacjaThe paper presents a computer module for GPS slant delay determination using data from COAMPS (Coupled Ocean/Atmosphere Mesoscale Prediction System) mesoscale non-hydrostatic model of the atmosphere which is run on IA64 Feniks computer cluster in the Department of Civil Engineering and Geodesy of the Military University of Technology. The slant delay is the result of integrating the ray (eikonal) equation for the spatial function...
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Investigation of noises in the EPN weekly time series
PublikacjaThe constantly growing needs of permanent stati ons’ velocities users cause their stability level to increase. To this research we included more than 150 stations located across Europe operating within the EUREF Permanent Network (EPN) w ith weekly changes in the ITRF2005 reference frame. The obvious long-range dependencies in the stochastic part of GPS time series were p roven by Ljung-Box...
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Analiza korelacji wyników zmęczeniowych badań łożysk ślizgowych
PublikacjaW pracy przedstawiono analizę korelacji wyników zmęczeniowych badań łożysk przeprowadzonych zgodnie z zaleceniami norm ISO. Przedmiotem analizy były wyznaczone graniczne wartości naprężeń obwodowych w warstwach ślizgowych panwi badanych w testerze SKMR-2 (zgodnym ze standardem ISO 7905/4) oraz w warunkach pełnego filmu smarowego na stanowiskach łożyskowych MWO i SMOK w Politechnice Gdańskiej.
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Influence of Installation Effects on Pile Bearing Capacity in Cohesive Soils – Large Deformation Analysis Via Finite Element Method
PublikacjaIn this paper, the whole process of pile construction and performance during loading is modelled via large deformation finite element methods such as Coupled Eulerian Lagrangian (CEL) and Updated Lagrangian (UL). Numerical study consists of installation process, consolidation phase and following pile static load test (SLT). The Poznań site is chosen as the reference location for the numerical analysis, where series of pile SLTs...
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Error analysis for European IGS stations
PublikacjaEach of the GPS time series that describes the changes of topocentric components consists of a deterministic and a stochastic part, whose character influences the errors of the deterministic parameters. As to the uncertainties of reliable velocities of permanent satellite station systems, surveys that estimate and take into account any dependencies that may affect subsequent operational efficiency are very important. For this analysis,...
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Proposal for calculating the bearing capacity of screw displacement piles in non-cohesive soils based on CPT results
PublikacjaPrzedstawienie wyników badań terenowych pali przemieszczeniowych wkręcanych, zrealizowanych w ramach projektu badawczego MNiSW. Propozycja dwóch metod obliczania nośności pali przemieszczeniowych wkręcanych w niespoistym podłożu gruntowym na podstawie wyników badań CPT. Metody dostosowano do wytycznych Eurokodu 7. Weryfikacja metod obliczeniowych z wynikami badań terenowych pali.
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Fretting wear of materials - methodological aspects of research
PublikacjaW artykule przedstawiono metodyczne aspekty frettingowego zużywania materiałów. Rezultaty badań przeprowadzonych na stanowisku typu ''pin on disc'' wykonanym w Katedrze Inżynierii Materiałowej i Biomedycznej Politechniki Białostockiej potwierdziły decydujący wpływ amplitudy oscylacji i wartości obciążenia na przebieg i charakter procesu zużywania. Wzrost wartości amplitudy powodował zmiany w warunkach tarcia. Wzrost wartości obciążenia...
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Influence of datasets decreased by applying reduction and generation methods on Digital Terrain Models
PublikacjaThe number of point clouds provided by LiDAR technology can be sometimes seen as a problem in development and further processing for given purposes (e.g. Digital Terrain Model (DTM) generation). Therefore, there is still a need to reduce the obtained big datasets. Reducing can be done, inter alia, by reducing the size of the set or by generating the set. This paper presents two variants of the reduction of point clouds in order...
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Large deformation finite element analysis of undrained pile installation
PublikacjaIn this paper, a numerical undrained analysis of pile jacking into the subsoil using Abaqus software suit has been presented. Two different approaches, including traditional Finite Element Method (FEM) and Arbitrary Lagrangian–Eulerian (ALE) formulation, were tested. In the first method, the soil was modelled as a two-phase medium and effective stress analysis was performed. In the second one (ALE), a single-phase medium was assumed...
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Effective Friction Angle Of Deltaic Soils In The Vistula Marshlands
PublikacjaThis article presents the results of laboratory tests on soft, normally consolidated soils from the Vistula Marshlands. Samples of high-plasticity organic soils (muds) taken from 3.2–4.0 m and 9.5–10.0 m depth, as well as peat deposit at 14.0 m, are analysed. Presented case study confirms the applicability of the Norwegian Institute of Technology (NTH) method based on Cone Penetration Tests (CPTU) and allows for a conservative...
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Modelling the time-dependent behaviour of soft soils
PublikacjaTime-dependence of soft soils has already been thoroughly investigated. The knowledge on creep and relaxation phenomena is generally available in the literature. However, it is still rarely applied in practice. Regarding the organic soils, geotechnical engineers mostly base their calculations on the simple assumptions. Yet, as presented within this paper, the rate-dependent behaviour of soft soils is a very special and important...
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Ceglana tożsamość. Dziedzictwo materialne jako rdzeń gdańskich tożsamości
PublikacjaArtykuł dotyczy cegły elewacyjnej jako materiału budowlanego będącego istotnym elementem kształtowania gdańskiej tożsamości.
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Application of non-classical operational calculus to indicate hazards in numerical solutions of engineering problems
PublikacjaThe article addresses the application of non- classical operational calculus to approximative solutions of engineering problems. The engineering-sound examples show that a continuous–discrete problem transformation from differential unequivocal problem to a differential wildcard problem, triggering a change in solution quality. A number of approximative methods are capable to alter both quantitative and qualitative...
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3D DEM SIMULATIONS OF BASIC GEOTECHNICAL TESTS WITH EARLY DETECTION OF SHEAR LOCALIZATION.
PublikacjaW artykule przedstawiono rezultaty numeryczne dla podstawowych testów geotechnicznych: testu trójosiowego ściskania oraz w aparacie bezpośredniego ścinania dla piasku bez kohezji. Wszystkie testy zostały wykonane w 3D, a piasek został wymodelowany w postaci kulek wraz z momentami symulującymi nieregularny kształt ziarna. Podczas badań sprawdzono wpływ parametrów fizycznych (m. in. początkowy wskaźnik porowatości, obciążenie pionowe...
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NEW EXPERIENCES IN DIKE CONSTRUCTION WITH SOIL-ASH COMPOSITESAND FINE-GRAINED DREDGED MATERIALS
PublikacjaThe supporting structure inside a coastal dike is often made of dredged non-uniform sand with good compaction proper-ties. Due to the shortage of natural construction material for both coastal and river dikes and the surplus of different processed mate-rials, new experiments were made with sand-ash mixtures and fine-grained dredged materials to replace both dike core and dikecover materials resulting in economical, environmentally...
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Static Load Test on Instrumented Pile – Field Data and Numerical Simulations
PublikacjaFor some time (since 8-10 years in Poland) a special static load tests on instrumented piles are carried out. Such studies are usually of a scientific nature and provide detailed quantitative data on the load transfer into the ground and characteristics of particular soil layers interaction with a pile shaft and pile base. Deep knowledge about the pile-subsoil interaction can be applied for a various design purposes, e.g. numerical...