Tez (Yüksek Lisans) - Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü, İnşaat Mühendisliği Anabilim Dalı, 2008. / Bibliyografya var.

The aim of the final thesis is to design steel structure of the sports hall in Brno. The design is processed in two options. The option "A" is designed in variant of flat space frame with dimensions 78x46,5 m and the structure height is 13,0 m. The option "B" is designed in variant of truss girder with parabolic lower belt and purlin. Dimensions are 84x46,5 m and the structure height is 12,8 m. Roof covering and curtain walling is made of sendwich panels with polyurethane foam and trapezoidal sheet.

This masters thesis concernes with design of formula student frame. Part of masters thesis is to a overview of possible solutions. The main criterion in frame design is final torsional stiffness. Another part of frame design is too solution of suspension attachement to frame. In next part of masters thesis is solved bodywork design and it´s fastening to frame. Final part has few informations about frame manufacturing.

The subject of this final thesis was to elaborate variant proposal and to assess supporting steel structure roof bus station in the shape of a hyperbolic paraboloid. 2 variants were proposed, one of which was chosen as a more appropriate and this was processed details and drawings. Both variants are used as cover glass panels. Structures are made of steel with 235J0.

A Windows based post processor for the design of reinforced concrete space frames is developed. The post processor is capable of designing beams and columns of reinforced concrete space frames in accordance with the ACI specification. The program is developed in C++ using the object oriented programming approach. The objects used in the program represents a one to one analogy with objects in the real world. The computer model of a structure is composed of objects like members, joints, loads, beams and columns. The development of the post processor is discussed and the program architecture is presented. The design results obtained from the post processor are compared with those obtained from several commercial structural design programs to ensure the correctness of the design. It was concluded that the application of object oriented programming techniques results in programs that are easier to develop and maintain and also greatly reduces the effort required for developing applications for graphical user interfaces. / Master of Science

The displacement method of the finite element is adopted. Both the updated Lagrangian formulation and total Lagrangian formulation of a three-dimensional beam element is employed for large displacement and large rotation, but small strain analysis. A beam-column element or finite element can be used to model geometrically nonlinear behavior of space frames. The two element models are compared on the basis of their efficiency, accuracy, economy and limitations. An iterative approach, either Newton-Raphson iteration or modified Riks/Wempner iteration, is employed to trace the nonlinear equilibrium path. The latter can be used to perform postbuckling analysis. / Ph. D.

A rather complete picture of automatic plastic-hinge analysis onto steel frames under static loads is made in the present thesis. One/two/three-linear behaviours of mild steel are considered. The frames are submitted to fixed or repeated load. The geometric nonlinearity is taken into account. The beam-to-column joints of structures could be rigid or semi-rigid. The compact or slender cross-sections are examined. The investigation is carried out using direct or step-by-step methods. Both analysis and optimization methodologies are applied. From the fundamental theory to the computer program aspect are presented. Various benchmarks in open literatures are tested demonstrating the efficiency of the implementation.

Foldable and deployable space structures refer to a broad category of pre-fabricated structures that can be transformed from a compact folded configuration to a predetermined expanded configuration. Such deployable structures are stable and can carry loads. These structures are also mechanisms with one degree of freedom in their entire transformation stages whether in the initial folded form or in the final expanded configuration. Usually, pantograph mechanisms or a scissor-like elements (SLEs) are part of such deployable structures. A new analysis tool to study kinematic and static analyses of foldable and deployable space structures /mechanisms, containing SLEs, has been developed in this thesis. The Cartesian coordinates are used to study the kinematics of large deployable structures. For many deployable structures the degree of freedom derived using the standard Grubler-Kutzback criteria, is found to be less than one even though the deployable structure /mechanism can clearly move. In this work the dimension of nullspace of the derivatives of the constraint equations are used to obtain the correct degrees of freedom of deployable structure. A numerical algorithm has been developed to identify the redundant joints /links in the deployable structure /mast which results in the incorrect degrees of freedom obtained by using the Grubler-Kutzback criteria. The effectiveness of the algorithm has been illustrated with several examples consisting of triangular, box shaped SLE mast and an eighteen-sided SLE ring with revolute joints. Further more the constraint Jacobian matrix is also used to evaluate the global degrees of freedom of deployable masts/structures. Closed-form kinematic solutions have been obtained for the triangular and box type masts and finally, as a generalization, extended to a general n-sided SLE based ring structure. The constraint Jacobian matrix based approach has also been extended to obtain the load carrying characteristics of deployable structures with SLEs in terms of deriving the stiffness matrix of the structure. The stiffness matrix has been obtained in the symbolic form and it matches results obtained from other commonly used techniques such as force and displacement methods. It is shown that the approach developed in this thesis is applicable for all types of practical masts with revolute joints where the revolute joint constraints are made to satisfy through the method of Lagrange multipliers and a penalty formulation. To demonstrate the effectiveness of the new method, the procedure is applied to solving (i) a simple hexagonal SLE mast, and (ii) a complex assembly of four hexagonal masts and the results are presented. In summary, a complete analysis tool to study masts with SLEs has been developed. It is shown that the new tool is effective in evaluating the redundant links /joints there by over coming the problems associated with the well –known Grubler-Kutzback criteria. Closed-form kinematic solutions of triangular and box SLE masts as well as a general n-sided SLE ring with revolute joints has been obtained. Finally, the constraint Jacobian based method is used to evaluate the stiffness matrix for the SLE masts. The theory and algorithms presented in this thesis can be extended to masts of different shapes and for the stacked masts.

The vibration of and wave propagation in periodic cellular structures are analyzed. Cellular structures exhibit a number of desirable multifunctional properties, which make them attractive in a variety of engineering applications. These include ultra-light structures, thermal and acoustic insulators, and impact amelioration systems, among others. Cellular structures with deterministic architecture can be considered as example of periodic structures. Periodic structures feature unique wave propagation characteristics, whereby elastic waves propagate only in specific frequency bands, known as "pass band", while they are attenuated in all other frequency bands, known as "stop bands". Such dynamic properties are here exploited to provide cellular structures with the capability of behaving as directional, pass-band mechanical filters, thus complementing their well documented multifunctional characteristics. This work presents a methodology for the analysis of the dynamic behavior of periodic cellular structures, which allows the evaluation of location and spectral width of propagation and attenuation regions. The filtering characteristics are tested and demonstrated for structures of various geometry and topology, including cylindrical grid-like structures, Kagom and eacute; and tetrhedral truss core lattices. Experimental investigations is done on a 2-D lattice manufactured out of aluminum. The complete wave field of the specimen at various frequencies is measured using a Scanning Laser Doppler Vibrometer (SLDV). Experimental results show good agreement with the methodology and computational tools developed in this work. The results demonstrate how wave propagation characteristics are defined by cell geometry and configuration. Numerical and experimental results show the potential of periodic cellular structures as mechanical filters and/or isolators of vibrations.

Morphing air vehicles enable more efficient and capable multi-role aircraft by adapting their shape to reach an ideal configuration in an ever-changing environment. Morphing capability is envisioned to have a profound impact on the future of the aerospace industry, and a reconfigurable wing is a significant element of a morphing aircraft. This thesis develops two tools for analyzing wing configurations with multiple geometric degrees-of-freedom: the structural tool and the aerodynamic and structural interaction tool. Linear Space Frame Finite Element Analysis with Euler-Bernoulli beam theory is used to develop the structural analysis morphing tool for modeling a given wing structure with variable geometric parameters including wing span, aspect ratio, sweep angle, dihedral angle, chord length, thickness, incidence angle, and twist angle. The structural tool is validated with linear Euler-Bernoulli beam models using a commercial finite element software program, and the tool is shown to match within 1% compared to all test cases. The verification of the structural tool uses linear and nonlinear Timoshenko beam models, 3D brick element wing models at various sweep angles, and a complex wing structural model of an existing aircraft. The beam model verification demonstrated the tool matches the Timoshenko models within 3%, but the comparisons to complex wing models show the limitations of modeling a wing structure using beam elements. The aerodynamic and structural interaction tool is developed to integrate a constant strength source doublet panel method aerodynamic tool, developed externally to this work, with the structural tool. The load results provided by the aerodynamic tool are used as inputs to the structural tool, giving a quasi-static aeroelastically deflected wing shape. An iterative version of the interaction tool uses the deflected wing shape results from the structural tool as new inputs for the aerodynamic tool in order to investigate the geometric convergence of an aeroelastically deflected wing shape. The findings presented in this thesis show that geometric convergence of the deflected wing shape is not attained using the chosen iterative method, but other potential methods are proposed for future work. The tools presented in the thesis are capable of modeling a wide range of wing configurations, and they may ultimately be utilized by Machine Learning algorithms to learn the ideal wing configuration for given flight conditions and develop control laws for a flyable morphing air vehicle.