This exam is about student’s perception of food and dietary advice. I illustrate food and eating from the youth's own perspective. The aim is to investigate how students perceive as "good" diet. It also reveals that students at the surveyed schools have poor knowledge of what is plate model. In the Swedish curriculum Lgr11 it is clear that the core content for students in grades 1-6 will contain the student include being informed about the selection and use of goods used in the home and how they in turn affect health (National Agency for Education, Lgr11: 43). I have interviewed students in grades 3 through focus groups to make it clear to you as readers to understand their own knowledge about nutrition.

The aerospace industry is increasingly coming to the conclusion that physics-based high-fidelity models need to be used as early as possible in the design of its products. At the preliminary design stage of wing structures, though highly desirable for its high accuracy, a detailed finite element analysis(FEA) is often not feasible due to the prohibitive preparation time for the FE model data and high computation cost caused by large degrees of freedom. In view of this situation, often equivalent beam models are used for the purpose of obtaining global solutions. However, for wings with low aspect ratio, the use of equivalent beam models is questionable, and using an equivalent plate model would be more promising. An efficient method, Equivalent Plate Analysis or simply EPA, using an equivalent plate model, is developed in the present work for studying the static and free-vibration problems of built-up wing structures composed of skins, spars, and ribs. The model includes the transverse shear effects by treating the built-up wing as a plate following the Reissner-Mindlin theory (FSDT). The Ritz method is used with the Legendre polynomials being employed as the trial functions. Formulations are such that there is no limitation on the wing thickness distribution. This method is evaluated, by comparing the results with those obtained using MSC/NASTRAN, for a set of examples including both static and dynamic problems. The Equivalent Plate Analysis (EPA) as explained above is also used as a basis for generating other efficient methods for the early design stage of wing structures, such that they can be incorporated with optimization tools into the process of searching for an optimal design. In the search for an optimal design, it is essential to assess the structural responses quickly at any design space point. For such purpose, the FEA or even the above EPA, which establishes the stiffness and mass matrices by integrating contributions spar by spar, rib by rib, are not efficient enough. One approach is to use the Artificial Neural Network (ANN), or simply called Neural Network (NN) as a means of simulating the structural responses of wings. Upon an investigation of applications of NN in structural engineering, methods of using NN for the present purpose are explored in two directions, i.e. the direct application and the indirect application. The direct method uses FEA or EPA generated results directly as the output. In the indirect method, the wing inner-structure is combined with the skins to form an "equivalent" material. The constitutive matrix, which relates the stress vector to the strain vector, and the density of the equivalent material are obtained by enforcing mass and stiffness matrix equities with regard to the EPA in a least-square sense. Neural networks for these material properties are trained in terms of the design variables of the wing structure. It is shown that this EPA with indirect application of Neural Networks, or simply called an Equivalent Skin Analysis (ESA) of the wing structure, is more efficient than the EPA and still fairly good results can be obtained. Another approach is to use the sensitivity techniques. Sensitivity techniques are frequently used in structural design practices for searching the optimal solutions near a baseline design. In the present work, the modal response of general trapezoidal wing structures is approximated using shape sensitivities up to the second order, and the use of second order sensitivities proved to be yielding much better results than the case where only first order sensitivities are used. Also different approaches of computing the derivatives are investigated. In a design space with a lot of design points, when sensitivities at each design point are obtained, it is shown that the global variation in the design space can be readily given based on these sensitivities. / Ph. D.

Le verre feuilleté est constitué de deux ou plusieurs feuilles de verre assemblées par une ou plusieurs couches de polymères viscoélastiques intermédiaires qui sont à l’origine des interactions entre les mécanismes de cisaillement, de flexion locale et de flexion globale qui régissent le comportement d’ensemble du verre feuilleté. Dans ces travaux, nous proposons un modèle de plaques dites "fortement contrastées" intégrant ces différents mécanismes et leur couplage. Dès lors qu’il existe une séparation d’échelle entre l’épaisseur de la plaque et la taille caractéristique des variations des champs cinématiques, la méthode des développements asymptotiques est applicable pour l’étude des stratifiées. Le comportement effectif de la plaque est dérivé de la loi de comportement 3D des matériaux, associée à une formulation de développements asymptotiques et à une mise à l’échelle appropriée du contraste de rigidité entre les couches raides de verre et des couches souples de polymère viscoélastique. Le procédé fournit une formulation explicite et cohérente, intégrant les efforts duaux des descripteurs macroscopiques (équations constitutives), les équations d’équilibres hors-plan et dans le plan et les différentes lois de comportements du stratifié. Le modèle est d’abord construit dans le cas d’une plaque de verre feuilleté à 2 couches raides puis différents cas de chargements statiques et dynamiques sont appliqués. Il est ensuite étendu aux plaques à 3 couches raides puis généralisé aux plaques à N couches raides. Des campagnes expérimentales sont mises en place pour valider les modèles obtenus. Enfin un cas d’étude de dimensionnement de plancher en verre feuilleté est proposé. / Widely used in recent years, the glass material makes it possible to erect light, aesthetic and resistant structures, in particular with glass lamination method, which consists in assembling two or more sheets of glass by one or more intermediate viscoelastic polymers layer. These viscoelastic interface layers are the source of interactions between the shear, the local bending and the global bending mechanisms that govern the overall behavior of laminated glass. For an optimal dimensioning and an accurate determination of the different fields, we propose a "highlycontrasted" plates model encapsulating these different mechanisms and their coupling. As long as a scale separation between the plate thickness and the caracteristic size of kinematics field variations exists, the asymptotic expansion method can be applied for the study of laminates. The effective plate behaviour is derived from the 3D constitutive law of the materials combined with an asymptotic expansion formulation and an appropriate scaling the tiffness contrast between stiff glass layers and soft viscoelastic polymer layers. The method provides a synthetic and consistent formulation, integrating the dual efforts of the macroscopic descriptors, in-plane and out-of-plane balance equations and the constitutive laws of the laminate. First the model is developped for a 2 stiff layers laminated glass plates, then different static and dynamic loading cases are applied. It is then extended to plates with 3 stiff layers and then generalized to plates with N stiff layers. Experimental campaigns are set up in order to validate the models. Finally, a case study of laminated glass floor design is proposed.

This thesis deals with the identification and regulation of the "Ball & Plate" model. The thesis contains a description of the existing real model and the relevant mathematical and simulation model. The root hodograph method and the state space method are used to calculate the controller, especially the feedback controller with integrator. The final part of the work is devoted to the 3D model construction using Simulink and SimScape, which describes and visualizes the behavior of the real model and enables simulation experiments to be performed quickly and easily.

The scope of thesis is to design a curved arch footbridge. The main structure consists of composite deck supported by steel arch. The focus is on finding optimal shape of arch and proper cross-sections of elements. Bridge is analysed according to limit states.

Composite laminated structures are prone to delamination. Rotorcraft flexbeams, apart from many other aerospace primary load carrying members are made up of composite laminated structures. A delaminated primary load carrying member can lead to catastrophic failure of the system of which it is a part. Delamination modeling and detection in composite laminated structures are challenging areas of ongoing research worldwide. Existing literature falls short of addressing effects of widthwise partial delamination on the modal characteristics of beams. To address this issue, a new partial delamination model for composite beams is proposed and implemented using the finite element method. Homogenized cross-sectional stiffness of the delaminated beam is obtained by the proposed analytical technique, including extension-bending, extension-twist and torsion-bending coupling terms, and hence can be used with an existing finite element method. A two-noded C1-type Timoshenko beam element with four degrees of freedom per node for dynamic analysis of beams is implemented. The results for different delamination scenarios and beams subjected to different boundary conditions are validated with available experimental results in the literature and/or with a 3-D finite element simulation using COMSOL. Results of the first torsional mode frequency for the partially delaminated beam are validated with the COMSOL results. The key point of the current work is that even partial delamination in long structures can be analyzed using a 1-D beam model, rather than using computationally more demanding 3-D or 2-D models. Rotor craft flexbeams are prone to delaminations, which in most realistic situations are partial along both the length and the width. However, the effect of partial delamination on the modal characteristics of the beam is not studied by researchers to the best of the author’s knowledge. Addressing this issue, a rotorcraft flexbeam is analysed here in the presence of delamination. A set of nonlinear governing equations for the rotating flexbeam are developed in hybrid basis. The flexbeam model developed has axial stretch, transverse displacement and flexural rotation in flapwise direction and twist as its degrees of freedom. The nonlinear governing differential equations are linearised and solved for eigenvalues and eigenvectors using a finite element method. The effects of angular speed and delamination size and location on the flexbeam modes are analysed. The results obtained using the proposed model are validated with the COMSOL 3-D finite element simulations. Next, the issue of delamination detection in beams is addressed. Mode shape curvature and Katz fractal dimension are used to detect the presence of partial delaminations in a beam. The effects of boundary conditions and location of delamination on the fractal dimension curve are studied. Usage of higher mode shape data for detection of delamination in beams is evaluated. Limitations of the Katz fractal dimension curve for delamination detection are enumerated. It is shown that fractal dimension measure and mode shape curvature can be used to detect the presence of partial delamination in beams. It is found that the torsional mode shape is best suited for partial delamination detection in beams. Apart from beams, Shell-and plate-like structures are also extensively used in aerospace structures. The modeling of multilayered plates is introduced herein with the intention to model delaminations in 2D. Carrera Unified Formulation(CUF)plate model, developed using variational formulations, is used to derive the stiffness matrices and to apply, the Principle of Virtual Displacement(PVD) and the Reissner Mixed Variational Theorem (RMVT). It is known that FEM implementation for plates leads to the phenomenon of numerical locking: the so-called membrane and shear locking effects. A well-known remedy for addressing locking is the use of the Mixed Interpolated Tensorial Components(MITC) technique. A strategy similar to MITC approach in the RMVT formulation is used to construct an advanced locking-free finite element to treat the multilayered plates. Composite laminated plates are prone to delamination. Implementation of delamination in the CUF frame work using nine-noded quadrilateral MITC9 elements is discussed. MITC9 elements are devoid of shear locking and membrane locking. Delaminated structures, as well as the corresponding healthy structures, are analysed for free vibration modes. The results from the present work are compared with those from available experimental or/and theoretical research articles or/and the 3-D finite element simulations. The effects of different kinds and different percentages of interfacial area of delaminations on the first three natural frequencies of the structure are discussed. The presence of the open-mode or breathing mode delamination mode shape for large delaminations within the first three natural frequencies is discussed. Also, the switching of the places between the second bending mode and the first torsional mode frequencies is discussed. Results obtained from different ordered theories are compared in the presence of delamination. Advantage of layer wise theory as compared to equivalent single layer theories for very large delaminations is stated. The effects of different kinds of delamination and its effect on the second bending and first torsional mode shapes are discussed.

The purpose of the diploma thesis is to design a expressway bridge over the river Vsetínská Bečva. The bridge is located between Valašské Meziříčí and Vsetín. Separate superstructures are designed for each directions of the expressway. The right superstructure, which is wider, is considered for detailed design. Two variants were proposed, A double T beam superstructure and a box girder superstructure. The three span box girder superstructure was chosen for the design. Spans are 48+65+48 m long. Two options of construction process of the superstructure were proposed. This bridge is designed according to the limit states, the influence of construction process is considered. Structural models of construction were made as a finite element model and a plate model. Structural analysis, drawings and visualization were developed.