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Search results for: LOAD
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Pedestrian bridge. Load and response
PublicationW pracy zdefiniowano dynamiczny model obciążenia pieszym w zależności od jego masy, rytmu chodu oraz drgań mostu. Zdefiniowana funkcja obciążenia zaimplementowana do komercyjnego programu MES, pozwala na symulacje dynamicznej odpowiedzi konstrukcji na zadane obciążenie. Przedstawiono dwa przykłady modelu teoretycznego w porównaniu z wynikami badań.
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Consideration of dynamic loads in the determination of axle load spectra for pavement design
PublicationAxle load spectra constitute a crucial part of the data for pavement design and pavement distress analysis. Typically, axle load spectra represent static load from vehicles and do not include dynamic loads generated by vehicles in motion. While dynamic loads can significantly contribute to faster pavement distress, this fact is mostly omitted in pavement design methods. The paper presents a methodology for consideration of dynamic...
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Load function walking pedestrian on the footbridge.
PublicationModern foot bridges are more and more sensitive to variable load created by moving pedestrians. These are several reasons for that. Quickly growing up road infrastructure forces us to build foot bridges just to reconnect one piece of land, separated now by the new road or railway. These bridges are lightweight because the only live load acting on them comes from pedestrians.The paper focuses on the definition of human induces dynamic...
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Stability and load bearing capacity of a braced truss under upward wind loading
PublicationThe paper is focused on the numerical and experimental investigation of stability of a steel truss under upward wind loading. The structure was stiffened by elastic braces situated at the top and bottom chord. Usually the lateral (translational) brace stiffness is considered. However, the rotational stiffness of braces caused by interaction between torsional stiffness of the truss top chord and bending stiffness of the roof elements...
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Stability and load bearing capacity of a braced truss under upward wind loading
PublicationThe paper is focused on the numerical and experimental investigation of stability of a steel truss under upward wind loading. The structure was stiffened by elastic braces situated at the top and bottom chord. Usually the lateral (translational) brace stiffness is considered. However, the rotational stiffness of braces caused by interaction between torsional stiffness of the truss top chord and bending stiffness of the roof elements...
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Load path sensitivity and multiaxial fatigue life prediction of metals under non-proportional loadings
PublicationEngineering components often operate under complex loadings, in which the variable amplitude multiaxial stresses are raised by geometric discontinuities including holes, grooves, fillets and shoulders, etc. Besides, the non-proportional loading will lead to the rotation of maximum principal stress/strain and additional fatigue damage of structural elements in service. Consequently, the multiaxial and non-proportional loading have...
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The flux compression generator load parameters selection
PublicationComputer simulation results of the flux compression generator (FCG) loaded with an inductor has been presented in this paper. Simulation research has been performed in order to select the parameters of FCG load coil properly. The influence of the load inductance and resistance on the current gain factor and the magnetic field energy accumulated in a load coil has been investigated.
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System load impact on VRRP advertisements delay
PublicationThe aim of the paper is to show how system load can affect network tasks (especially VRRP advertising depending on factors such as kernel schedu-ler [3] version, kernel settings and load priority. Two versions of the Linux kernel will be used: 2.6.22 (with "O(1) scheduler) and 2.6.23 (with "CFS" scheduler). "vrrpd" version 0.4 is used as an VRRP protocol implementation.
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A method of nonlinearities of transformer no-load characteristic modelling
PublicationA way in which changes of the no-load characteristic are taken into account in the mathematical model of the transformer is presented. Changes of saturation within core of transformer are presented as a combined non-linear flux curve. Analysis of magnetization of the transformer core and simulation of no-load state for distribution transformer of 30 kVA power rating and 15.75/0.4 kV/kV (especially supplying VLV) transformation...
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Load-settlement characteristics of piles working in a group
PublicationLoad-settlement characteristic (Q-s) of an axially loaded pile can be empirically determined from a static pile load test or on the basis of calculations using, e.g. transfer functions or numerical methods (FEM). The transfer functions method usually rely on empirical data, i.e. the function parameters are determined on the basis of numerous pile test results. Thus this method takes into account pile installation technology and...
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Korzyści z zastosowania układów Load Sensing
PublicationW artykule porównano układy Load Sensing I i II rodzaju z układem z dwudrogowym regulatorem przepływu. Dokonano oceny mocy traconych oraz korzyści stosowania układów LS w stosunku do tradycyjnych rozwiązań
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Biocompatibility and Bioactivity of Load-Bearing Metallic Implants
PublicationThe main objective of here presented research is to develop the titanium (Ti) alloy base composite materials possessing better biocompatibility, longer lifetime and bioactivity behaviour for load-bearing implants, e.g. hip joint and knee joint endoprosthesis. The development of such materials is performed through: modeling the material behaviour in biological environment in long time and developing of new procedures for such evaluation;...
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Load testing of a suspended footbridge in Radom (Poland)
PublicationThe footbridge in Radom is a suspended bridge of an interesting architectural form. The structure was de-signed for 4 kN/m2 of crowd loading. Dynamic calculations were not included in the design. The structure’s acceptance tests took place on the 14th of October 2016. The behaviour of the footbridge in static testing met the expectations. Unfortunately, as a result of dynamic tests, dangerous behaviour of the footbridge was revealed....
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Ice Load Characteristics on Floating Photovoltaic Platform
PublicationNowadays, based upon human needs and preferring perpetual types of energy, photovoltaic system (PV) is a suitable alternative and more frequently used in northern countries, which are recently more attracted by solar power. The new floating type of the structure is installed in the water bodies instead of land. One of the main elements in floating photovoltaic structures is the forces imposed on the panels. In the northern regions,...
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Biocompatibility and bioactivity of load-bearing metallic implants
PublicationThe main objective of here presented research is to develop the titanium (Ti) alloy base composite materials possessing better biocompatibility, longer lifetime and bioactivity behaviour for load-bearing implants, e.g. hip joint and knee joint endoprosthesis. The development of such materials is performed through: modeling the material behaviour in biological environment in long time and developing of new procedures for such evaluation;...
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Bearing testing machine with rotating load vector.
PublicationW pracy przedstawiono koncepcję konstrukcyjną i prototyp stanowiska badawczego z wirująca reakcją łożyskową przeznaczonego do testowania wytrzymałości zmęczeniowej warstw ślizgowych w łożyskach poprzecznych. Konstrukcja i przeznaczenie maszyny zbudowanej w laboratorium tribologicznym Politechniki Gdańskiej jest zgodna z zaleceniami normy ISO 7905. Przeanalizowano zalety i wady maszyny badawczej o takim wzorcu obciążenia testującego.
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Load Testing of GFRP Composite U-Shape Footbridge
PublicationThe paper presents the scope of load tests carried out on an innovative shell composite footbridge. The tested footbridge was manufactured in one production cycle and has no components made from materials other than GFRP laminates and PET foam. The load tests, performed on a 14-m long structure, were the final stage of a research program in the Fobridge project carried out in cooperation with: Gdańsk University of Technology (leader),...
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Heuristic scheduling algorithms for uniform load of computer system
PublicationW pracy zaprezentowano opracowany heurystyczny algorytm szeregowania zadań UNILO (ang. UNIform LOad - jednakowe obciążenie), umożliwiający redukcję całkowitego zapotrzebowania na moc obliczeniową systemu komputerowego bez pogarszania jego wydajności. Algorytm ten realizuje takie przydzielenie zadań obliczeniowych do poszczególnych jednostek (procesorów), aby zapewnić ich jednakowe obciążenie. Opracowany algorytm został zweryfikowany...
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INFLUENCE OF LOAD AND INFLATION PRESSURE ON THE TYRE ROLLING RESISTANCE
PublicationTyre load and inflation pressure are important factors controlling rolling resistance of road vehicles. The article presents results obtained in the Technical University of Gdańsk during laboratory and road measurements of different car tyres rolling on different pavements. The knowledge of rolling resistance characteristics is important for modelling car dynamics as well as fuel consumption. It is also necessary to establish proper...
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The Influence of External Load on the Performance of Microbial Fuel Cells
PublicationIn this work, the effect of the external load on the current and power generation, as well as on the pollutant removal by microbial fuel cells (MFCs), has been studied by step-wise modifying the external load. The load changes included a direct scan, in which the external resistance was increased from 120 Ω to 3300 Ω, and a subsequent reverse scan, in which the external resistance was decreased back to 120 Ω. The reduction in the...
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Stability and load bearing capacity of a truss with elastic braces
PublicationThe present paper is devoted to the numerical and experimental investigations of stability of a truss stiffened by elastic braces. The model of a real roof truss scaled by factor ¼ was investigated. In the research the linear buckling and non-linear static analysis of the truss shell and beam model with geometric and material non-linearity is presented. The initial imperfections were assumed in the form of the first buckling mode....
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Performance of organic coatings upon cyclic mechanical load
PublicationA number of engineering structures fail due to the fatigue damage resulting from cyclic mechanical stress. However, as far as organic coatings are concerned this degradation factor remains underestimated. In the paper the authors propose a methodology combining global electrochemical impedance spectroscopy and local atomic force microscopy measurements for evaluation of coating resistance to an impact of repetitive mechanical stress. Typical...
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A probabilistic concept of load assessment of self-ignition engines
PublicationPrzedstawiono propozycję probabilistycznej interpretacji obciążenia silników spalinowych o zapłonie samoczynnym. Zaproponowano probabilistyczny opis obciążenia tych silników z uwzględnieniem znanych parametrów (wskaźników) ich pracy. Wykazano, że obciążenie tego rodzaju silników, rozpatrywane w dowolnej chwili, może być uważane za zmienną losową. Zwrócono uwagę, że obciążenie to może być uważane za zmienną losową wielowymiarową....
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The association between allostatic load and brain: A systematic review
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Dynamic load tests of piles in non-cohesive soils.
PublicationThe results of investigations of various types of piles, the analysis of dynamic tests carried out recently in Poland and the correlations between the results of dynamic and static tests of piles are presented. Przedstawiono wyniki badań nośności różnych rodzajów pali, analizę badań dynamicznych wykonanych w Polsce w ostatnich latach oraz korelacje pomiędzy wynikami badań statycznych i dynamicznych.
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Numerical analysis of cylindrical shell subjected to explosive load
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Analysis of transverse load of saw in wood cutting process
PublicationW pracy przedstawiono przyczyny, rodzaje i efekty poprzecznego obciążenia zarówno pojedynczego ostrza, jak również wypadkowego obciążenia piły w procesie przecinania drewna. Dokonano rozkładu całkowitej siły odporowej na składową wolną- i szybkozmienną. Przedstawiono skutki wpływu poszczególnych rodzajów poprzecznego obciążenia pił na dokładność obróbki.
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Bioactive core material for porous load-bearing implants
PublicationSo far state of knowledge on biodegradable materials is reviewed. Among a variety of investigated materials, those composed of polymers and ceramics may be considered as only candidates for a core material in porous titanium alloy. The collagen and chitosan among natural polymers, polyhydroxy acids among synthetic polymers, and hydroxyapatite and tricalcium phosphate among ceramics are proposed for further research. Three essential...
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Shortening and non linear load settlement behaviour of piles.
PublicationPrzedstawiono praktyczne wartości współczynnika B do obliczeń skrócenia trzonu pali. W analizie zastosowano metodę funkcji transformacyjnych t-z oraz q-z. Wykorzystano wyniki próbnych obciążeń statycznych pali, w sumie 184 pali próbnych.
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Load-carrying capacity of axially loaded concrete-filled steel tubular columns made of thin tubes
PublicationAn experimental investigation was conducted on 30 CFST columns. An influence of the following factors on load-carrying capacity of the investigated columns was analyzed: the column slenderness (l1 = 42, l2 = 27 and l3 = 15), the tube thickness (the reinforcement ratio was equal to 4% or 6%), the way of applying the load to CFST columns (through the concrete core or through the entire cross-section), the bond strength between a...
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Underfrequency Load Shedding: An Innovative Algorithm Based on Fuzzy Logic
PublicationIn contemporary power systems, the load shedding schemes are typically based on disconnecting a pre-specified amount of load after the frequency drops below a predetermined value. The actual conditions at the time of disturbance may largely dier from the assumptions, which can lead to non-optimal or ineective operation of the load shedding scheme. For many years, increasing the eectiveness of the underfrequency load shedding (UFLS)...
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Analysis of the Impact of Charging Electric Cars on the Power System Load
PublicationThe paper presents ways of integrating electric cars with the power system. In connection with this, daily load curves in the average working day have been developed in the G2V (Grid-to-Vehicle) and V2G (Vehicle-to-Grid) variants. The G2V solution consists in unidirectional energy flow from the power system to a vehicle’s battery. The V2G solution consists in bi-directional energy exchange between the power system and electric...
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Correlation between natural frequencies and buckling load in a stiffened shell
PublicationThe paper deals with correlation between natural frequencies and buckling load of a stiffened shell composed of corrugated sheets and vertical stiffeners (columns). The simplified shell segment represents the buckling behaviour of a whole silo with sparsely distributed columns. The paper covers variants of linear buckling anal-yses, dynamic eigenvalue analyses and geometrically non-linear analyses of a segment modelled with shell...
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Displacement measurements during load testing of railway arch bridge
PublicationThe paper discusses issues concerning load tests carried out on a twin-track, arch railway bridge over the Martwa Wisla river in Gdansk. Currently, it is the bridge with the longest span in its class in Poland. The load-bearing structure consists of three no-hinge arches and an orthotropic deck suspended from them. The studies of the structure assumed the performing of static and dynamic tests. The paper presents the method for...
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High load capacity spur gears with conchoidal path of contact
PublicationThe present study is devoted to investigation of spur gears with a conchoidal path of contact and a convex-convex contact between teeth. The load capacity and energy efficiency were evaluated using both theoretical and experimental approaches. The theoretical analysis showed that the conchoidal gear pairs are 5–21% stronger in terms of contact stress and have similar energy efficiency as compared to the involute gear pairs of the...
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Static load test on concrete pile – instrumentation and results interpretation
PublicationFor 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...
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Experimental Study of Dapped-End Beams Subjected to Inclined Load
PublicationThis paper presents the results of an experimental investigation of the reinforced concrete (RC) dapped-end beams loaded with inclined forces, compared to identical ones loaded with vertical forces only. Such a load may occur in, for example, Gerber's joints or in dapped-end beams supported on corbels, where the vertical gravitation force is additionally completed with horizontal forces caused by temperature differences, shrinking,...
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Investigation of stability and limit load of a truss overhead opened bridge
PublicationThe paper presents selected methods of determining stability and limit load of a truss top chord in opened bridges. These methods include linear buckling and non-linear static analysis based on the finite element method and algorithms based on design code procedures. The described methods were tested on an example of a steel footbridge situated in Straszyn. The results of stability analysis are compared. The results of geometrical...
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Study on the accuracy of axle load spectra used for pavement design
PublicationWeigh-in-Motion (WIM) systems are used in order to reduce the number of overloaded vehicles. Data collected from WIM provide characteristics of vehicle axle loads that are crucial for pavement design as well as for the development of pavement distress prediction models. The inaccuracy of WIM data lead to erroneous estimation of traffic loads and in consequence inaccurate prediction of pavement distress process. The objective of...
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Load Tests of the Movable Footbridge Over the Port Canal in Ustka
PublicationThe paper presents the acceptance tests carried out on the open footbridge over the port canal in the Port of Ustka. The steel footbridge construction is created by a single pylon to which a movable truss span is suspended with a theoretical span of 52.3 m. The studies about load test of the object included static and dynamic extortion and measurements. In static tests the ballast was of pallets with concrete blocks. Dynamic studies...
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An in situ technique for the assessment of adhesive properties of a joint under load
PublicationSlow crack propagation in adhesive bonded joints has been characterised using an asymmetric wedge test. Crack position was evaluated from strain gauge measurements, both in the debonded partof the joint and in the bonded zone. Test temperature was changed during loading, giving insight into bond evolution. The technique allows accurate, and virtually continuous, determination of crack position to be made, and therefore the evaluation...
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DISPLACEMENT MEASUREMENTS DURING LOAD TESTING OF THE RAILWAY ARCH BRIDGE
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Cam mechanism designing with account of the technological load and energy costs
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Propeller Load Modelling In The Calculations Of Marine Shafting Torsional Vibrations
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The influence of compressive gear on maximal load lifted in competitive powerlifting.
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Refining and integrating schizophrenia pathophysiology – Relevance of the allostatic load concept
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Modeling of Wireless Traffic Load in Next Generation Wireless Networks
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Dynamic response of the PEM fuel cell to step change load
PublicationPrzedstawiono charakterystyki dynamiczne ogniwa paliwowego typu PEM o mocy 2.5 kW obciążanego sygnałem skokowym o wartościach od 1 A do 50 A.
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Dynamic response of the PEM fuel cell to variable load conditions
PublicationOpisano układ zasilania oparty na 2 ogniwach paliwowych typu PEM o mocy 1.2 kW każde. Omówiono problem ograniczenie ogniwa paliwowego przez drugą zasadę termodynamiki. Przedstawiono charakterystyki układu w zależności od sygnału obciążenia typu: skok jednostkowy, półsinusoidalny, trójkątny, prostokątny i trapezowy.
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EXPERIMENTAL STUDY OF A TEMPORARY STEEL GRANDSTAND UNDER CROWD LOAD
PublicationTemporary structures, such as grandstands, are commonly used during different types of mass events, especially sport and music concerts. In this paper, the results of the experimental study on temporary steel grandstand are presented. The aim of the investigation was to determine modal characteristics of such structures. Modes of free vibrations and corresponding natural frequencies have been obtained for empty and occupied grandstand....