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Wyniki wyszukiwania dla: FEM

Influence of nonlinearities on the efficiency and accuracy of FEM calculations on the example of a steel buildup thinwalled column
PublikacjaDue to the increase of computing capabilities of standard processing units, it is possible to perform complex analyses, considering a number of nonlinearities, such as geometric, material and boundary (contact) even on personal computers. In the paper, the authors have analysed the efficiency and accuracy of standard PC’s FEM calculations performed in Abaqus CAE 2017 software on the example of a critical load assessment of a thinwalled...

FEM Calculations in Analysis of Steel Subsea Water Injection Flowlines Designing Process
PublikacjaPaper describes the result of theoretical research aimed at assessing the loads and operating conditions of a Coiled Tubing pipeline injecting water, suspended to the mining platform of Lotos Petrobaltic. For this purpose, appropriate calculation models have been developed using the Finite Element Method (FEM), taking into account the nature of the analyzed object and its loads. The analyzes were carried out for two pipes (previously...

DEMFEM model of highly saturated soil motion due to seepage force
PublikacjaArtykuł poświęcono nowej propozycji rozwiązania problemu modelowania zjawiska transportu, które występuje wewnątrz wysokonawodnionego gruntu ziarnistego na skutek ciśnienia spływowego. Teoria oparta została na połączeniu metody elementów skończonych (FEM  Finite Element Method)  rozwiązania równań poroelastycznych oraz metody poszczególnych elementów (DEM  Distinct Element Method), które dały podwójny model numeryczny. FEM...

A GPU Solver for Sparse Generalized Eigenvalue Problems with Symmetric ComplexValued Matrices Obtained Using HigherOrder FEM
PublikacjaThe paper discusses a fast implementation of the stabilized locally optimal block preconditioned conjugate gradient (sLOBPCG) method, using a hierarchical multilevel preconditioner to solve nonHermitian sparse generalized eigenvalue problems with large symmetric complexvalued matrices obtained using the higherorder finiteelement method (FEM), applied to the analysis of a microwave resonator. The resonant frequencies of the loworder...

Ultrasonic Tomography of Brick Columns Based on FEM Calculations
PublikacjaUltrasonic tomography is one of the most developed method of nondestructive testing. Despite being used mainly in medicine, it is becoming more and more popular as a method for monitoring of structural elements. It allows to examine the internal structure and technical condition of the tested element. This paper investigates the influence of crosssectional geometry on an obtained tomographic image. Wave propagation signals were...

On the influence of shell element properties on the response of car model in crash test
PublikacjaIt goes without saying that numerical simulations play important role in the modern engineering practice. Contemporary CAD environments combined with FEM solvers, along with computer power of modern processors, give the engineer fast and efficient tool. Ultimately, however it is the user alone who is responsible for the correctness of the results. As long as the FEM calculations remain in the sphere of academic exercise, the inevitable...

Diagonalized Macromodels in Finite Element Method for Fast Electromagnetic Analysis of Waveguide Components
PublikacjaA new technique of local modelorder reduction (MOR) in 3D finite element method (FEM) for frequencydomain electromagnetic analysis of waveguide components is proposed in this paper. It resolves the problem of increasing solution time of the reducedorder system assembled from macromodels created in the subdomains, into which an analyzed structure is partitioned. This problem becomes particularly relevant for growing size and...

Determination of the minimal critical rotational speeds of the circular saw blades with the quasitwin resonant frequencies
PublikacjaTo determine the minimal critical rotational speeds of the circular saw blades is the fundamental aspect of obtaining the range of the rotational operating speeds, by which the circular saw blade can work with required stability. While for the circular saw blades with fullhomogeneous bodies the determination of such rotational speeds is the relatively low level of difficulty function, whereas for circular saw blades with more...

CFD and FEM model of an underwater vehicle propeller
PublikacjaDuring the project execution of design and optimization the Remotely Operated Vehicle (ROV) research on its propulsion has been carried out. The entire project was supported by CFD and FEM calculations, which taking into account the characteristics of underwater vehicle. One of the tasks was to optimize the semiopen duct for horizontal propellers, which provided propulsion and controllability in horizontal plane. In order to...

Single and DualGPU Generalized Sparse Eigenvalue Solvers for Finding a Few LowOrder Resonances of a Microwave Cavity Using the FiniteElement Method
PublikacjaThis paper presents two fast generalized eigenvalue solvers for sparse symmetric matrices that arise when electromagnetic cavity resonances are investigated using the higherorder finite element method (FEM). To find a few loworder resonances, the locally optimal block preconditioned conjugate gradient (LOBPCG) algorithm with nullspace deflation is applied. The computations are expedited by using one or two graphical processing...

Modal analysis of railway current collectors using Autodesk Inventor
PublikacjaThe paper presents the results of modal analysis of railway current collector type 160EC. In the first place, the analysis was carried out analytically for a simplified two lumped mass pantograph model. Then numerical analysis was conducted in the Autodesk Inventor (AI) on the prepared multibody model using the AI modal analysis algorithm, which is based on the finite element method (FEM). Model elements which are most relevant...

Macromodels for efficient FEM simulations of waveguides and resonators
PublikacjaThis paper introduces a novel technique for enhancing the efficiency of the finite element method (FEM) by incorporating special modules, called macromodels, into the standard eigenvalue formulation. The number of unknowns in the separated macromodel subdomain can be significantly reduced by orthogonal projection, using the efficient nodal order reduction algorithm. The idea of macromodels implementation is demonstrated on a simple...

Novel analysis methods of dynamic properties for vehicle pantographs
PublikacjaTransmission of electrical energy from a catenary system to traction units must be safe and reliable especially for high speed trains. Modern pantographs have to meet these requirements. Pantographs are subjected to several forces acting on their structural elements. These forces come from pantograph drive, inertia forces, aerodynamic effects, vibration of traction units etc. Modern approach to static and dynamic analysis should...

The impact of the shape of deep drilled well screen openings on the filtration process in full saturation conditions
PublikacjaThe authors propose a supplementary method of modelling seepage flow around the deep drilled well screen. The study applies 3D numerical modelling (FEM) in order to provide an indepth analysis of the seepage process. The analysis of filtration parameters (flow distribution q(x,t) and pressure distribution p) was conducted using the ZSoil.PC software system. The analysis indicates that the shape of perforation is of secondary importance...

TB11 test for short wbeam road barrier
PublikacjaFEM (Finite Element Method) is wellsuited and widely used tool for simulating a range of phenomena: from these with simple and static behaviour, up to those complicated, highly nonlinear and involving many contacts. In present paper we use one of the advantages of FEM: parametric study could be easily performed and is more economical than series of insitu tests. If recommended practices is carefully followed, results obtained...

Numerical simulation of a thinwalled beam with warping stiffeners undergoing torsion
PublikacjaW pracy rozwinięto koncepcję zastosowania superelementów węzłowych do modelowania stężeń konstrukcyjnych w belkach cienkościennych. Przeprowadzono analizę pracy belek cienkościennych o bisymetrycznym przekroju otwartym ze stężeniami bimomentowymi w formie przepon i przewiązek.

Distortional buckling of composite thinwalled columns of a boxtype cross section with diaphragms
PublikacjaDistortional buckling of axially compressed columns of boxlike composite cross sections with andwithout internal diaphragms is investigated in the framework of onedimensional theory. The channel membersare composed of unidirectional fibrereinforced laminate. Two approaches to the member orthotropic materialare applied: homogenization based on the theory of mixture and periodicity cells, and homogenization basedon the Voigt–Reuss...

FEM approach to modeling of an irregular trabecular structure
PublikacjaThe aim of the study is elaboration of a method for creating irregular scaffolds that can be used to model the behaviour of trabecular bone placed in the proximal epiphysis of the femur. The scope of the study encompasses creating six numerical models of irregular scaffolds (two solid irregular scaffolds, two shell irregular scaffolds and two shell irregular scaffolds with fortification) and performing numerical analysis of the...

FEM simulation of laminate failure in the three point bending
PublikacjaThe paper presents a FEM simulation of failure of laminate subjected to the three point bending. The numerical model is based on the equivalent single layer approach with 6paramater nonlinear shell theory kinematics. It is implemented in the noncommercial FEM code. The failure initiation is detected with the use of TsaiWu criterion. After the failure onset the progressive failure process is modelled through the appropriate...

NonDestructive Testing of a Sport Tribune under Synchronized CrowdInduced Excitation Using Vibration Analysis
PublikacjaThis paper presents the concept of repairing the stand of a motorbike speedway stadium. The synchronized dancing of fans cheering during a meeting brought the stand into excessive resonance. The main goal of this research was to propose a method for the structural tuning of stadium stands. Nondestructive testing by vibration methods was conducted on a selected stand segment, the structure of which recurred on the remaining stadium...

An Analysis of Cylindrical Posts of Arbitrary Convex Cross Sections Located in Waveguide Junctions with the Use of Field Matching Method
PublikacjaA problem of electromagnetic wave scattering from cylindrical posts of arbitrary cross section located in waveguide junction is presented. The method of analysis is based on the direct ﬁeld matching technique. Multimode scattering matrices of every section of waveguide junction are calculated and cascading procedure is utilized to investigate the whole structure. The results are veriﬁed by comparing them with those obtained from...

Numerical analysis of pile installation effects in cohesive soils
PublikacjaIn this thesis the empirical equation for radial effective stress calculation after displacement pile installation and following consolidation phase has been proposed. The equation is based on the numerical studies performed with Updated Lagrangian, Arbitrary LagrangianEulerian and Coupled EulerianLagrangian formulations as well as the calibration procedure with database containing worldwide 30 pile static loading tests in cohesive...

Structural Reliability Assessment Of Corroded Tanker Ship Based On Experimentally Estimated Ultimate Strength
PublikacjaThis work deals with the reliability assessment of a tanker ship hull structure subjected to a vertical bending moment and corrosion degradation. The progressive collapse and ultimate load carrying capacity are estimated based on experimentally tested scaled boxshapedspecimens. The translation of the strength estimate of the scaled specimen to the real tanker ship hull structure is performed based on the dimensional theory developing...

A DISCRETECONTINUOUS METHOD OF MECHANICAL SYSTEM MODELLING
PublikacjaThe paper describes a discretecontinuous method of dynamic system modelling. The presented approach is hybrid in its nature, as it combines the advantages of spatial discretization methods with those of continuous system modelling methods. In the proposed method, a threedimensional system is discretised in two directions only, with the third direction remaining continuous. The thus obtained discretecontinuous model is described...

Study of displacements of a bridge abutment using FEM
PublikacjaSteel sheet piles are often used to support excavations for bridge foundations. When they are left in place in the permanent works, they have the potential to increase foundation bearing capacity and reduce displacements; but their presence is not usually taken into account in foundation design. In this article, the results of finite element analysis of a typical abutment foundation, with and without cover of sheet piles, are presented...

A twoscale (FEMDEM) approach for concrete
PublikacjaArtykuł omawia dwuskalowe podejście do betonu przy wykorzystaniu modelu Mes i DEM. Metodę elementów skończonych zastosowano na poziomie makro. Na poziomie mikro zastosowano metodę elementów dyskretnych. Macierz sztywności wyznaczono na podstawie tensora naprężeń wyznaczonego w skali mikro. Wyniki numeryczne dwusalowe porównano z wynikami dyskretnymi dla całego obszaru.

Study on 19thcentury cast iron columns from the former financial office building in Kwidzyn
PublikacjaThe article presents the results for cast iron columns used as floor supports in the former financial office building in Kwidzyn (Poland).The stocktaking drawings provided the general and detailed data about the 19th century designer’s decisions. During the research, architectural and structural analysis was carried out. The graphics were used as a starting material for preparing 3D calculation models. The FEMbased numerical simulations...

Finite element method simulations of various cases of crash tests with N2/W4/A steel road barrier
PublikacjaThe subject of this study is performance of N2/W4/A steel road safety barrier investigated in numerical simulations. System was checked under several types of initial conditions, which were assumed basing on the TB11 and TB32 normative crash tests. The main goal of present study is to investigate the relationship between initial conditions (angle and velocity) of the impact and the severity indices (associated to the vehicle occupant) during...

Wave Frequency Effects on Damage Imaging in Adhesive Joints Using Lamb Waves and RMS
PublikacjaStructural adhesive joints have numerous applications in many fields of industry. The gradual deterioration of adhesive material over time causes a possibility of unexpected failure and the need for nondestructive testing of existing joints. The Lamb wave propagation method is one of the most promising techniques for the damage identification of such connections. The aim of this study was experimental and numerical research on...

Comparative modeling of shear localization in granular bodies with FEM and DEM
PublikacjaThe intention of the paper is to compare the calculations of shear zones in granular bodies using two different approaches: a continuum and a discrete one. In the first case, the FEM based on a micropolar hypoplastic constitutive law was used. In the second case, the DEM was taken advantage of, where contact moments were taken into account to model grain roughness. The comparative calculations were performed for a passive case...

Inverse heat transfer problem solution of sounding rocket using moving window optimization
PublikacjaAn Inverse Heat Transfer Problem is solved for a sounding rocket module given its geometry and measured temperature profile. The solution is obtained via moving window optimization, a technique for solving inverse dynamics. An analysis is performed to modify the method to avoid oscillatory behavior of the resulting heat flux profile. The method parameters are tuned in relation to characteristic phases of the flight. Results are...

Nonlinear Modeling in Time Domain Numerical Analysis of Stringed Instrument Dynamics
PublikacjaMusical instruments are very various in terms of sound quality with their timbre shaped by materials and geometry. Materials' impact is commonly treated as dominant one by musicians, while it is unclear whether it is true or not. The research proposed in the study focuses on determining influence of both these factors on sound quality based on their impact on harmonic composition. Numerical approach has been chosen to allowed independent...

The statistical impact of experimental result scatter of asphalt mixtures on their numerical modelling
PublikacjaThe paper presents selected test results of asphalt mixture conducted in low temperatures. The obtained parameters are highly diverse. It concerns ultimate breaking loads, stiffness parameters related to Young's modulus but also the fracture course. Statistical analysis upon the results makes it possible to relevantly estimate the materialdefining parameter values. Such a random approach leads to the mean values of breaking and...

Spectral Methods for Modelling of Wave Propagation in Structures in Terms of Damage Detection—A Review
PublikacjaModern methods of detection and identification of structural damage direct the activities of scientific groups towards the improvement of diagnostic methods using for example the phenomenon of mechanical wave propagation. Damage detection methods that use mechanical wave propagation in structural components are extremely effective. Many different numerical approaches are used to model this phenomenon, but, due to their universal...

Effect of mesh deformation on the accuracy of 3D FEM electromagnetic analysis
PublikacjaIn this paper, the accuracy of 3D FEM electromagnetic simulations in parametric analysis using mesh deformation techniques is discussed. Mesh deformation techniques allow one to preserve the mesh topology while the geometry is changed. It is shown that the application of mesh deformation can provide accurate simulation results even for very large deformations. On the other hand, it is also shown that the technique has to be used...

FEM ANALYSIS AND EXPERIMENTAL TESTS OF RIGID RISER HANGING SYSTEM
PublikacjaThe article presents the analysis, project, and experimental examination of an original rigid riser for Coil Tubing Pipes. The principle of riser operation is based on the use of friction forces. The research included the FEM analysis of the designed riser, calculations of the required bolt tensions, and checking the effect of the clamping force on stress distribution in the pipeline. The results of computer simulation were verified...

Vibration of the bridge under moving singular loads  theoretical formulation and numerical solution
PublikacjaThe paper presents the results of the numerical analysis of a simple vehicle passing over a simply supported bridge span. The bridge is modelled by a EulerBernoulli beam. The vehicle is modelled as a linear, viscoelastic oscillator, moving at a constant speed. The system is described by a set of differential equations of motion and solved numerically using the RungeKutta algorithm. The results are compared with the solution...

Mechanical behaviour of the implant used in human hernia repair under physiological loads
PublikacjaIn laparoscopic operations of abdominal hernias some recurrences still take place, even when applying a surgical mesh. This is usually caused by a failure of the connection between the tissue and the implant. The study deals with the influence of an implant’s orientation on forces in joints, which connect the mesh to human tissues. In the paper, the implant is modelled as a membrane structure within framework of the Finite Element...

Guided wave propagation for assessment of adhesive bonding between steel and concrete
PublikacjaAdhesive bonding is becoming more increasingly important in joining of structural elements. In civil engineering, there is a growing interest in connection by adhesive bonding in steelconcrete flexural members. This study concerns the guided wave propagation technique applied to condition assessment of an adhesive connection between a steel member and a concrete beam. Various states of degradation were considered by producing...

Young’s modulus distribution in the FEM models of bone tissue
PublikacjaThis paper presents how differences of Young’s modulus in adjacent finite elements typical for organic materials such as bone tissue, influence stress calculating. Emphasizing high computational cost of variable Young’s modulus in parts of the model, where the number of finite elements has been raised, the authors wants to prove that new model of finite element which has variable Young’s modulus in its volume needs to be created....

Continuous and discontinuous modeling of fracture in concrete using FEM
PublikacjaW monografii przedstawiono wyniki obliczeń numerycznych procesu pękania w betonie. Obliczenia wykonano stosując metodę elementów skończonych. Zastosowano 2 podejścia: ciągłe i nieciągłe. Jako podejścia ciągłe przyjęto model sprężystoplastyczny, model degradacji sztywności, model rys ciągłych oraz model połączony sprężystoplastyczny z degradacją sztywności. Wszystkie modele zostały rozszerzone o długość charakterystyczną mikrostruktury...

NonDestructive Assessment of Masonry Pillars using Ultrasonic Tomography
PublikacjaIn this paper, a condition assessment of masonry pillars is presented. Nondestructive tests were performed on an intact pillar as well as three pillars with internal inclusions in the form of a hole, a steel bar grouted by gypsum mortar, and a steel bar grouted by cement mortar. The inspection utilized ultrasonic stress waves and the reconstruction of the velocity distribution was performed by means of computed tomography. The...

Analysis of guided wave propagation in adhesive joints of steel rods
PublikacjaThe aim of the study is the elastic wave propagation in adhesive joints of metal rods that are one of the simplest kind of glue connections. They are consisted of two metal members and an adhesive layer joining two parts together. The analysis is directed to technical diagnostics of such type of connections. Longitudinal and transversal guided waves were excited in prepared joints. Signals of propagating waves were registered in...

DESIGN AND CONSTRUCTION OF TILTED WALLS IN ACCORDANCE WITH CODES' PROVISIONS ON THE EXAMPLE OF THE CONSTRUCTION OF THE MUSEUM OF THE SECOND WORLD WAR IN GDAŃSK
PublikacjaThe purpose of this article was to introduce the design and construction of tiled walls in accordance to codes' restrictions. The construction of the Museum of the Second World War in Gdańsk was chosen to be an example of its successful use in practice. Theoretical knowledge was based on PNEN 199211:2008 and fib Model Code for Concrete Structures 2010. Although codes' recommendations seem curt, practice prove structural advance....

Numerical Modelling of Connections Between Stones in Foundations of Historical Buildings
PublikacjaThe aim of this paper is to analyse the behaviour of old building foundations composed of stones (the main loadbearing elements) and mortar, based on numerical analysis. Some basic aspects of historical foundations are briefly discussed, with an emphasis on their development, techniques, and material. The behaviour of a foundation subjected to the loads transmitted from the upper parts of the structure is described...

A New Type of MacroElements for Efficient TwoDimensional FEM Analysis
PublikacjaThis letter deals with a model order reduction technique applicable for driven and eigenvalue problems solved using the finite element method (FEM). It allows one to efficiently compute electromagnetic parameters of structures comprising small features that require strong local mesh refinement. The subdomains of very fine mesh are separated from the global domain as so called macroelements that undergo model reduction. The macroelements...

FEM approach to estimate the behaviour of biocomposite metalsurface coating system
PublikacjaA three dimensional (3D) model of biocomposite metalsurface coating system, which is influenced byknown external forces, is proposed. This model consists of the metallic substrate (Ti6Al4V) and thehydroxyapatite (HA) coating. Using FEM (finite element method), strainstress maps of model weregenerated for investigating relations between the extreme stress of HA coating and the magnitude ofexternal force and the thickness of the...

The FEM analysis of pressure installation elements after simulated accidental overheating
PublikacjaThe paper presents innovative analysis focused on the safety aspects of existing pressure installation operation after overheating accidents. Results presented here can be applied in decisionmaking process concerning further operation of existing pressure installation after cooling system failure. In this paper the results of FEM analysis performed for a straight pipe and 90 degrees elbow, made of super duplex stainless steel,...

Reference FEM model for SHM system of cablestayed bridge in Rzeszów
PublikacjaThe paper presents the references model for structural health monitoring system (SHM) of cablestayed bridge recently constructed in Rzeszów over Wisłok River. The SHM system is design to provide online information on the structure state and facilitate its maintenance procedures. The main feature of the SHM system is permanent observation of the dynamic behavior of the bridge with focus on cable vibrations. The paper discusses...

Comparison of natural frequencies of a circular saw blade obtained empirically and with FEM
PublikacjaThe knowledge of the natural frequencies’ values of circular saw blades is necessary to determine the minimal critical rotational speed in which they can work with required stability. Moreover, testing the circular saw blades with more complicated shapes, e.g. which have additional holes inside blades for cleaning knifes or additional indirect teeth in gullets, reveals some kind of problematic properties of these saw blades. The...