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EN
In this study, the elastic wave propagation method is used to observe the initiation and evolution of the fatigue failure form in the multilayered composite plate with an elliptical hole. The experimental tests with the use of active, pitch-catch elastic wave measurement techniques are used during the fatigue test of the composite specimens. The fatigue tests were preceded by the numerical, finite element analysis of the elastic wave propagation phenomenon in a composite plate with an elliptical hole. The sequential measurement related to the number of cycles during the fatigue tests was assumed. The time of flight (ToF) and amplitude change was monitored by piezoelectric sensors localized in the area of predictable failure form evolution. The analysis of the dynamic response of the structure under fatigue loading conditions by a relatively small number of piezoelectric transduces allows us to build cost-effective Structural Health Monitoring (SHM) system for damage detection and monitoring of the failure form evolution.
EN
The problem of dynamic stability of composite three-layered annular plate with viscoelastic core is the subject of the consideration. Plate composed of thin outer layers and soft core is loaded quickly in time with forces compressing facings and with temperature gradient in radial direction. Two kinds of plate support system are analysed: plate slideably clamped in thermo-mechanical problem and plate clamped on both edges in thermal analysis. The analytical and numerical solution, which is based on the orthogonalization and finite difference methods includes axisymmetric and asymmetric forms of buckling and rheological properties of plate core.
3
Content available remote The influence of Helmholtz and Golay coil homogenity on rectangular plate bending
EN
The subject of the paper is a rectangular plate. The structure of the plate issymmetrical. The plate is made of a cellular structure of a core and two external faces. There isferrofluid in each cell of the porous core. The core is made of polyethylene foam and two facesare polyurethane sheets. It is assumed that cells in the core are regular and dense and the facesare thin, therefore, a plate filled in with ferrofluid can be treated as homogeneous. The plateis placed in the magnetic field. The magnetic field is generated by two systems of coils – theHelmholtz coil (HC ) and the Golay coil (GC). The former generates an almost fixed magneticfield in the considered volume (where the plate is placed), and the latter generates a gradientmagnetic field. The changing size of each subsystem of magnetic field coils, the distribution andstrength of the magnetic field change as well. The magnetic field induces loads in the plate,both perpendicular and in plane. The plate bending function is approximated by the bicubicspline function presented by normalized B-spline functions. The influence of changes in thehomogeneity volume and the magnetic field strength (by changing the coil size) on the platebending is analyzed in the paper. The results of the analysis are presented in tables and figures.
PL
Zastosowanie prefabrykacji w budownictwie inżynieryjnym wydatnie skraca czas realizacji inwestycji i ogranicza koszty społeczne, zwłaszcza jeżeli prefabrykaty mogą być wielkowymiarowe a zarazem lekkie, wytrzymałe i trwałe. Takie warunki spełniają prefabrykaty kompozytowe wykonane w technologii InfraCore® Inside. Technologia wytwarzania kompozytowych elementów FRP pozwala wykonywać wielkogabarytowe monolityczne elementy prefabrykowane w jednym procesie infuzji z powtarzalną jakością wykonania i w dowolnym kształcie.
EN
The present research studied fault diagnosis of composite sheets using vibration signal processing and artificial intelligence (AI)-based methods. To this end, vibration signals were collected from sound and faulty composite plates. Using different time-frequency signal analysis and processing methods, a number of features were extracted from these signals and the most effective features containing further information on these composite plateswere provided as input to different classification systems. The output of these classification systems reveals the faults in composite plates. The different types of classification systems used in this research were the support vector machine (SVM), adaptive neuro-fuzzy inference system (ANFIS), k-nearest neighbor (k-NN), artificial neural networks (ANNs), Extended Classifier System (XCS) algorithm, and the proposed improved XCS algorithm. The research results were reflective of the superiority of ANFIS in terms of precision,while this method had the highest process duration with an equal number of iterations. The precision of the proposed improved XCS methodwas lower than that of ANFIS, but the duration of the processwas shorter than the ANFIS method with an equal number of iterations.
EN
Paper presents the sensitivity of the three-layered plate structure on the acting of mechanical and thermal loads. The cases of the annular plates, whose individual layers: facings and core have homogeneous building and/or heterogeneous one expressed by the variable material properties in radial direction have been examined. Numerical investigations have been carried out modelling the select examples of plate structure with the use of the finite element method. Plate is loaded in the plane of facings or is subjected to the flat temperature field. The evaluation of the structure sensitivity has been carried out analysing the values of critical loads or critical temperatures and corresponding with them buckling modes. Numerous results presented in diagrams create the image of plate behaviours, show responses of plate structure and indicate on the means of structure designs, which can fulfil the expected conditions of plate work.
EN
In this study, a finite element based formulation is developed for analyzing the buckling and post-buckling of composite laminates subjected to mechanical and hygrothermal loads using Modified Hyperbolic Shear Deformation Theory (MHSDT). The changes in the critical buckling load are presented for different lamination schemes, thicknesses, material properties and plate aspect ratios. In addition, post buckling analysis is performed for a composite plate subjected to uniform in-plane thermal and moisture induced loadings by using MHSDT. Matlab software has been used for programming the analysis. The results obtained by Matlab codes are in a satisfactory consistence compared to the references. Thus, the developed MHSDT has been validated for buckling and post buckling analysis of laminated plates in hygrothermal environment.
EN
This paper presents the capabilities of ABAQUS finite-element program [1] in modelling sandwich beams and plates resting on deformable foundations. Specific systems of sandwich beams and plates separated by an elastic core layer were subjected to the action of point and distributed moving loads. A few theoretical examples are provided to present different techniques of modelling the foundations and the moving loads. The effects of the boundary conditions and of the foundation parameters on the deflections of the analysed structures are also presented.
PL
Ograniczeniem zastosowania metod analitycznych do rozwiązania zagadnień dynamicznych belek i płyt pod obciążeniami ruchomymi są przede wszystkim trudności w spełnieniu warunków brzegowych w belkach i płytach. Z tego też powodu w większości przypadków stosuje się metody przybliżone typu MES, MECZ, MEB, DQM oraz metodę różnic skończonych, w których łatwo jest zamodelować dowolne warunki brzegowe. Metody te pozwalają również na uwzględnienie różnorodności materiałów i elementów konstrukcyjnych. W niniejszej pracy przedstawiono możliwości wykorzystania programu metody elementów skończonych (MES) ABAQUS [1] do modelowania belek i płyt warstwowych spoczywających na odkształcalnych podłożach. Układy takie poddano działaniu ruchomych obciążeń, zarówno skupionych jak i rozłożonych. W kilku przykładach pokazano różne techniki modelowania podłoża i ruchomego obciążenia.
EN
The subject of this paper are thin composite rectangular plate. The plates are made of two families of ribs and homogeneous material of a matrix. The main feature of the considered plates is, that a distance between the ribs is comparable to the thickness of the plate. The widths of the ribs can vary slowly in the midplane of the plate. This allows you to get a desirable frequency of natural vibrations of the plate. The formulation of averaged model equations is based on the tolerance averaging approach (Wozniak et al. 2008, 2010). The general results of the contribution are illustrated using the analysis of natural vibrations of the plates under consideration. It will be carried out validation of the obtained mathematical model by comparison of results from obtained model equations with results from finite elements method (Abaqus program).
PL
W pracy przedstawiono technologię wytwarzania wielowarstwowych, wielkogabarytowych płyt kompozytowy kształtowanych metodą prasowania próżniowego. Wskazano zalety i możliwości zastosowania płyt kompozytowych, jako nowoczesnego materiału do budowy systemów transportu specjalnego przeznaczenia zastępującego tradycyjne zabudowy stalowe i aluminiowe. Przedstawiono przykłady rozwiązań konstrukcyjnych mobilnych systemów transportu specjalistycznego. W budowie ścian, dachów, podłóg, drzwi użyto płyt kompozytowych o szczególnych wymaganiach wytrzymałościowych, estetycznych i higienicznych. Dzięki zastosowaniu lekkich i wytrzymałych płyt kompozytowych i zastosowanej technologii ich łączenia uzyskano wytrzymałe na skrajne warunki atmosferyczne, sztywne, lekkie i funkcjonalne pozbawione wszelkich mostków termicznych, o bardzo dobrych parametrach izolacyjnych mobilne systemy kontenerowe.
EN
At work shows the manufacturing technology of multi-layered, large size composite plate, shape with vacuum pressing method. Indicated advantages and opportunities to use of composite panels as modern material to build special transport systems to replace traditional steel and aluminum buildings. Shows examples of design solutions to mobile systems of specialist transport. In the constructions of walls, roofs, floors and doors used composite plate with special endurance esthetic and hygienic requirements. Thanks to the use of light and durable composite plate and technology to combine them to gained resistant to bad weather conditions, rigid, light and functional devoid of any thermal bridge with very good insulation parameters of mobile container systems.
EN
The work deals with the issues of modelling of multiscale composites. A group of composite structures with a quasi-fractal geometry has been defined. In order to model their dynamic properties, a simple engineering method has been proposed. It takes into account not only the parameters and proportions of the components of the composite, but also their mutual arrangement. The proposed method is demonstrated on several examples and its accuracy has been compared with the finite element method and the homogenization method.
EN
In the continuum mechanics there is a class of problems that cannot be solved directly or the solutions of these problems are affected by large errors when the classical equations of thermoviscoelasticity are considered. The paper discusses a special case of such problems - the cyclic bending of a composite plate with a circular hole subjected to the stationary self-heating, which was solved within the framework of a moment theory of thermoviscoelasticity.
EN
The wavelet transform is one of the most effective tools for many tasks concerning signal and image processing, however it is difficult to obtain all of the necessary properties in one scalar wavelet. This leads to the development of new types of transforms such as a multiwavelet transform, which possesses more than one scaling and wavelet function and makes a possibility to combine these functions in order to obtain necessary properties. In the present study the CL2, LV and DGHM multiwavelets were used for an identification of spatial damage in a composite plate based on the analysis of its modal shapes. The obtained results show that some properties of the multiwavelet transform may improve the damage identification algorithm and replace the classical wavelet-based methods
14
Content available remote Programming of composite plates damage calculation
EN
The goal of this paper is to present the numerical results of elastic damage of thin unidirectional fiber-reinforced composite plates. The numerical implementation uses a layered shell finite element based on the Kirchhoff plate theory. Newton-Raphson method is used to solve the system of nonlinear equations and evolution of damage has been solved using return-mapping algorithm. The analysis is performed by finite element method and user own software is created in MATLAB programming language. One problem for two different materials was simulated in order to study the damage of laminated fiber reinforced composite plates.
15
Content available remote Symulacja uszkodzenia płyty kompozytowej pod wpływem obciążeń udarowych
PL
Praca przedstawia symulację numeryczną powstawania uszkodzeń w płycie kompozytowej na skutek dwóch następujących po sobie uderzeń wgłębnika o znanej energii. Przewidywanie skali uszkodzenia powstającego w tym procesie jest szczególnie interesujące z punktu widzenia symulacji komputerowych. W pracy przedstawiono sposób modelowania oraz walidację eksperymentalną dla przypadku dwunastowarstwowej prostokątnej płyty kompozytowej. Wykorzystano komercyjny pakiet metody elementów skończonych LS-Dyna oraz kohezyjny model kontaktu pomiędzy warstwami laminatu. Uzyskano bardzo dobrą zgodność z danymi eksperymentalnymi co dowodzi przydatności symulacji komputerowych w projektowaniu struktur kompozytowych z uwzględnieniem ich uszkodzenia.
EN
The paper presents simulation of damage prediction in composite plate induced by two subsequent low velocity impacts of known energy. Damage prediction in this type of conditions is especially interesting from the numerical point of view. The paper contains the description of the numerical model of a twelve ply composite plate and details related to the definition of simulation case. Commercial finite element solver LS-Dyna has been used to perform simulations. Very good agreement with experimental data has been obtained, which is an indication that numerical simulations can be used effectively in predicting damage in composite structures.
16
Content available remote Programming of composite plates damage calculation
EN
The goal of this paper is to present the numerical results of elastic damage of thin unidirectional fiber-reinforced composite plates. The numerical implementation uses a layered shell finite element based on the Kirchhoff plate theory. Newton-Raphson method is used to solve the system of nonlinear equations and evolution of damage has been solved using return-mapping algorithm. The analysis is performed by finite element method and user own software is created in MATLAB programming language. One problem for two different materials was simulated in order to study the damage of laminated fiber reinforced composite plates.
17
Content available remote Vibration Suppression of Composite Plate with MFC Active Elements
EN
Application of the Macro Fiber Composite (MFC) as active elements for suppression of composite plate vibrations is presented in this paper. Vibrations are reduced by the Nonlinear Saturation Control (NSC) method. Effectiveness of the algorithm is tested in Matlab package using a reduced model of a plate. The numerical results are verified experimentally.
EN
In the article an example of modelling of a composite plate CFEP with a piezoelectric patch was shown. Models were created with the use of FE software ANSYS. A numerical experiment was carried out. The aim of the experiment was to identify the first ten eigenfrequencies of the composite plate. Obtained data was analyzed with use of MATLAB software. In the article selected results of the research were presented.
PL
W artykule przedstawiono przykład modelowania płyty kompozytowej CFEP z materiałem piezoelektrycznym, który połączony był zkompozytem na dwa sposoby: położony był na powierzchni płyty kompozytowej oraz wbudowany w kompozyt. Modele zostały utworzone z zastosowaniem oprogramowania ANSYS. Przeprowadzono eksperyment numeryczny majacy na celu identyfikację wartosci pierwszych dziesieciu częstotliwości drgan własnych płyty kompozytowej w zalezności od wymiarów aktuatora piezoelektrycznego i wartości napięcia zasilającego piezoelektryk. Przedstawiono wyniki przeprowadzonych badan.
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