Abstract This study focuses on the development of a plate-shell element using the vector form intrinsic finite element (VFIFE) method to analyze the structural behavior of thin shell structure subjected to various exerting forces. The shell element employed here is the flat three-node triangular shell element proposed by Bathe and Ho, which is obtained by superimposing CST (constant strain triangle) element with DKT (discrete Kirchhoff theory) triangular plate element. The nodal coordinates, displacements, rotations, and the motion equations of the structure are defined in a fixed global set of coordinates. The strains of the shell element, the element internal nodal forces and the element stiffness matrix are defined in terms of co-rotational coordinates, which are corresponding to the configuration of the shell element. Based on the co-rotational coordinate principle, the nodal displacement between two adjacent time steps can be separated into displacements induced from rigid body motion or deformation, and the incremental internal nodal forces can also be obtained. Finally, following the Newton's 2nd law, the equations of motion can be built to analyze the dynamic responses of thin shell structures. The theory derived in this study, were further verified to be able to simulate the behavior of thin shell structures subjected to both static and dynamic loadings. This new analytical model was proved to be an effective tool that can be an alternertive to traditional finite element procedure to solve for complicated engineering problems in thin shell structures.

In the last years multilevel preconditioners like BPX became more and more popular for solving second-order elliptic finite element discretizations by iterative methods. P. Oswald has adapted these methods for discretizations of the fourth order biharmonic problem by rectangular conforming Bogner-Fox-Schmidt elements and nonconforming Adini elements and has derived optimal estimates for the condition numbers of the preconditioned linear systems. In this paper we generalize the results from Oswald to the construction of BPX and Multilevel Diagonal Scaling (MDS-BPX) preconditioners for the elasticity problem of thin smooth shells of arbitrary forms where we use Koiter's equations of equilibrium for an homogeneous and isotropic thin shell, clamped on a part of its boundary and loaded by a resultant on its middle surface. We use the two discretizations mentioned above and the preconditioned conjugate gradient method as iterative method. The parallelization concept is based on a non-overlapping domain decomposition data structure. We describe the implementations of the multilevel preconditioners. Finally, we show numerical results for some classes of shells like plates, cylinders, and hyperboloids.

As an operational approach to the Bekenstein-Hawking formula S_{BH}=A/4l_{Pl}^{2} for the black hole entropy, we consider the reversible contraction of a spinning thin shell to its event horizon and find that its thermodynamic entropy approaches $S_{\mathrm{BH}}$. In this sense the shell, called a "black shell", imitates and is externally indistinguishable from a black hole. Our work is a generalization of the previous result [10] for the spherical case. We assume the exterior space-time of the shell is given by the Kerr metric and match it to two different interior metrics, a vacuum one and a non-vacuum one. We find the vacuum interior embedding breaks down for fast spinning shells. The mechanism is not clear and worth further exploring. We also examine the case of a Kerr-AdS exterior, without trying to find a detailed interior solution. We expect the same behavior of the shell when the horizon limit is approached.

As an operational approach to the Bekenstein-Hawking formula S_{BH}=A/4l_{Pl}^{2} for the black hole entropy, we consider the reversible contraction of a spinning thin shell to its event horizon and find that its thermodynamic entropy approaches $S_{\mathrm{BH}}$. In this sense the shell, called a "black shell", imitates and is externally indistinguishable from a black hole. Our work is a generalization of the previous result [10] for the spherical case. We assume the exterior space-time of the shell is given by the Kerr metric and match it to two different interior metrics, a vacuum one and a non-vacuum one. We find the vacuum interior embedding breaks down for fast spinning shells. The mechanism is not clear and worth further exploring. We also examine the case of a Kerr-AdS exterior, without trying to find a detailed interior solution. We expect the same behavior of the shell when the horizon limit is approached.

The purpose of this thesis is to study behaving of thin reinforced concrete shell structure with a huge span which overcomes two hundred meters. The main goal is to find an ideal shape of such structure to ensure only compression without bending tension which allows us to cover huge area with a very thin shell. For solution of internal forces was used the finite elemet method (ANSYS).The blueprints of shape of this shell are the part of this project.

This diploma thesis deals with a steel construction of crab frame of ladle crane with lifting capacity of 120 and 40 tons and maximum lifting height of 21 meters. The aim of the work is analysis and assessment of the support frame of crane with a load of fatigue according to ČSN 27 0103/89. For this analysis is used thin shell and beam model. The diploma thesis was developed in cooperation with the Královopolska a.s. company.

The topic of my Diploma’s thesis is a fatigue analyzing and judgmenting of main frame casting cat bridge crane. Use the beam model and thin shell model for comparising. The thesis contains of both of computation model. The loading states results of computation model are attachmented of this thesis. This diploma’s thesis was created for Kralovopolska a.s. company.

GPS 單點定位或稱絕對定位，傳統上使用虛擬距離觀測量，容易受到 電離層延遲影響，導致定位精度較差。因此，本文的目的為構建即時的區 域性電離層模型，以便能夠即時減弱電離層延遲量，提高單頻GPS 單點定 位的精度。 構建電離層模型的方法有很多種，而運用類神經網路為可能方法之一， 但是， 國內較少人探討。本研究嘗詴使用倒傳遞類神經網路(Back-propagation Artificial Neural Network)，構建即時的區域電離層模型，藉由選擇適當的神經訓練函數及隱藏層神經元，利用過去收集的已知參考站的雙頻GPS 資料，計算電離層延遲量，訓練類神經網路，直到精度合乎要求；再以檢核站GPS 資料，檢驗類神經網路預測電離層延遲的功效。 採用的實驗資料為臺南市政府e-GPS 系統所提供六個測站，2008 年1 月3 日到1 月5 日的GPS 資料，計算測站與GPS 衛星連線中假想的電離層 薄殼交點—電離層穿透點(Ionosphere Pierce Point, IPP）之地理位置(緯度φ、經度λ)，及太陽黑子數(sunspot numbers)等當作輸入值，IPP 的垂直電離層延遲當作輸出值，測詴包含單日、兩日以及不同的資料型態(IPP 點、網格點)等情況訓練類神經網路，藉由相對應的驗證資料，檢驗類神經網路的功效，最後將類神經網路的預估成果與全球電離層改正模型、雙頻GPS 資料計算的電離層延遲相比較，並根據改正率與統計特性，評估類神經網 路構建出的區域性電離層模型的成效。 由實驗成果顯示，構建的即時區域性電離層模型的標準差可小於±3TECU，並可改正約80%的電離層延遲誤差，故以類神經網路可有效的構 建出區域性的電離層模型。 / The conventional single point positioning using GPS pseudo rangemeasurements, are vulnerable to ionospheric errors, leading to poor positioningaccuracy. Constructing a real-time ionospheric model is one of the methods that can reduce the ionospheric errors and improve the single point positioning accuracy. Although there are many methods to construct regional ionosphere model,using artificial neural network (ANN) to construct a real-time ionospheric model is less to be mentioned. This study used back-propagation artificial neural network to estimate a regional real-time ionospheric model by selecting the appropriate training functions and the number of hidden layers and its’ nodes. The neural network had to be ‘trained’ by the computed TECs from reference stations’ duel-frequency GPS data until the required accuracy was achieved. The experimental data are collected from 6 e-GPS stations of Tainan city government on January 3 to January 5, 2008. The input values for the ANN includ the geographical location of the ionosphere pierce point (IPP) and solar activity (sunspot number). The output value are those IPPs’ vertical total electron content (VTEC). Different times range and data types (IPPs’ or raster data) for the impact of the ANN are tested. And then compared to Klobuchar model and global ionopheric model, according to the correct rate and the ΔTEC statistic table decide the effectiveness of ANN. According to the test results, the regional ionopheric model constructed by ANN can corrected 80% of the ionospheric errors, the standard deviation of ΔTEC is less than ±3TECU.

Space-based telescopes are limit by the payload requirements of existing launch vehicles. Thus, despite distinct advantages the resolution of terrestrial telescopes exceeds space-based telescopes due to larger size and powerful adaptive optics. To overcome payload limitations, a primary mirror technology that is lighter in weight, but no less effective, is required. As this will result in new structural conditions, new approaches to maintaining the optical shape (figure) of the mirror will also be required. This thesis culminates work at the Georgia Institute of Technology in modelling a hexagonal thin-shell deformation mirror manipulated by an adaptive truss. This research specifically examines the feasibility of a surface parallel actuated (SPA) thin-shell CuZr deformable mirror (DM) as an alternative to a typical surface normal actuated (SNA) based mirror. It is believed that by using a thin-shell mirror (100 m or less in thickness) with a light weight substrate, such as a truss, that a significant weight-savings will occur, thus enabling larger space based telescopes. This thesis advances the SPA DM concept by 1) creating a representative model, 2) developing design evaluation methods, 3) evaluating the FEA simulated response of the deformable mirror over Zernike error modes, 4) evaluating the FEA simulated response to select thermal loads, and 5) evaluating the ability of the DM to remove thermal error, and the forces required to do so. Finally, it is concluded that overall the SPA DM concept is feasible.

In the last years multilevel preconditioners like BPX became more and more popular for solving second-order elliptic finite element discretizations by iterative methods. P. Oswald has adapted these methods for discretizations of the fourth order biharmonic problem by rectangular conforming Bogner-Fox-Schmidt elements and nonconforming Adini elements and has derived optimal estimates for the condition numbers of the preconditioned linear systems. In this paper we generalize the results from Oswald to the construction of BPX and Multilevel Diagonal Scaling (MDS-BPX) preconditioners for the elasticity problem of thin smooth shells of arbitrary forms where we use Koiter's equations of equilibrium for an homogeneous and isotropic thin shell, clamped on a part of its boundary and loaded by a resultant on its middle surface. We use the two discretizations mentioned above and the preconditioned conjugate gradient method as iterative method. The parallelization concept is based on a non-overlapping domain decomposition data structure. We describe the implementations of the multilevel preconditioners. Finally, we show numerical results for some classes of shells like plates, cylinders, and hyperboloids.