Few decades ago, there were no guidelines for torsion design of reinforced concrete (RC) beams. Hence, many existing beams in older buildings have a lack of adequate torsional strength since they were not properly designed for torsion. One way to regain/rehabilitate adequate torsional strength is through application of externally bonded carbon fiber reinforced polymers (CFRP). To date, American Concrete Institute (ACI) code, as well as other building codes, do not have recommendations or provisions for strengthening RC beams for torsion using fiber-reinforced polymer (FRP) composites due to the inexistence of conclusive experimental and analytical data. Of the very limited works on this behavior, the majority of the focus has been devoted to experimental works. Realistic spandrel beams in a building that lack torsional strength were modelled in this research, and strengthened to examine various behaviors such as load capacity, deflection, torque, twist, crack propagation, ductility, and failure modes. For this purpose, six RC beams were tested: four reference beams and two strengthened beams were used to observe additional capacity through the use of carbon fiber-reinforced polymer (CFRP) sheets. To strengthen the beams, one layer of sheets was completely wrapped around them. Results show an additional torsional capacity of 63% and 178% relative to their respective reference beams. Through strengthening, modes of failure of the beams changed from brittle torsion-dominated failure to shear-flexure failure in both beams. The study also included crack pattern and ductility of test beams. Cracks became smaller in width and more evenly distributed across the torsion-loaded area, and torsional ductility was enhanced by 266% and 165% respectively. Flexural ductility was also greatly enhanced by more than five folds. Finally, using ACI 318-14, ACI 440.2R-02, and available formulae in the literature, the beams were analyzed and the respective values were compared.

No description available.

Orientador: Euripedes G. O. Nobrega / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-24T03:12:13Z (GMT). No. of bitstreams: 1 Khater_Evaldo_D.pdf: 6371414 bytes, checksum: 2bbb7e16fb992bc5ae751840e548a367 (MD5) Previous issue date: 1998 / Resumo: O presente trabalho visa o desenvolvimento de estratégias de controle de vibração torcional em sistemas rotativos, com o objetivo de atenuar os modos significativos da vibração em regime. O controle ativo é empregado através de um controlador neural multicamada, usando o método da retropropagação do erro. O sistema é realimentado através do próprio motor elétrico (CC) do acionamento. Uma bancada experimental de um sistema rotativo é utilizada para o ajuste do modelo, teste do controlador ótimo (LQR) e na emulação do modelo experimental usando rede neural multicamada para treinar o controlador adequado ao sistema real. Um circuito eletrônico embarcado na extremidade do eixo flexível, transmite o sinal amplificado da deformação angular indicada por uma ponte de extensômetros elétricos. Resultados satisfatórios foram encontrados tanto na simulação computacional como nos testes experimentais, demonstrando que um controlador neural pode ser uma boa alternativa para os sistemas rotativos reais / Abstract: The purpose of this work is the development of control strategies of torsional vibration in rotating systems, with the objective of minimizing the significant modes of torsional vibration in steadystate. The active control was employed through a multilayer neural network controler, using back-propagation, feeding the system with the same driving electric motor (DC). A experimental model of the rotating system was employed to adjust the theorical model, test the optimal controler (LQR) and emulation the experimental model using a multilayer neural network to train the appropriate controler to the real system. A electronic circuit attached at the end of flexible shaft sends the amplified signal of angular strain measured. Satisfactory results were found both in the computacional simulation and in the experimental tests, showing that a neural controler can be a good choice for real rotating systems / Doutorado / Mecanica dos Sólidos e Projeto Mecanico / Doutor em Engenharia Mecânica

Orientador: Rene Brenzikofer / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Educação Fisica / Made available in DSpace on 2018-07-19T06:10:52Z (GMT). No. of bitstreams: 1 Ortale_RenataLanducci_M.pdf: 1976071 bytes, checksum: 279fd16f5e25de85f875d6b90acfe76d (MD5) Previous issue date: 1993 / Resumo: O propósito deste trabalho é apresentar um método para análise quantitativa e tridimensional da coluna vertebral em posição estática. O método apresentado utiliza registros fotográficos estereoscópicos, medição das imagens em mesa digitalizadora e análise dos dados através de programas computacionais, os quais foram desenvolvidos para agilizar os procedimentos da reconstrução e fornecer resultados quantitativos, sob a forma de gráficos, das curvaturas e das torções geométricas 3D da espinha. A reconstrução 3D dos pontos antõmicos, marcados na pele sobre os processos espinhosos da coluna vertebral, foi desenvolvido por BRENZIKOFER (1991, 1993). A análise matemática em termos de curvatura e torção geométrica 3D dos pontos anatômicos é obtida a partir de um ajuste polinomial por quadrados mínimos. Aplicamos este método em três voluntários, os quais foram submetidos a uma avaliação postural clinica, antes da realização dos experimentos fotográficos. Os pontos anatômicos foram marcados com adesivos autocolantes e contrastantes nos indivíduos na posição ereta e estática, prontos para serem fotografados. Os pontos de interesse, estenderam-se da base do occipital até o processo espinhoso da quarta vértebra lombar, somando um total de vinte pontos. Os resultados obtidos são apresentados sob a forma de seis gráficos, para cada sujeito: dois correspondem ao ajuste polinomial das projeções das curvas da coluna vertebral nos planos sagital e frontal, outros dois às curvaturas bidimensionais nos mesmos planos, um à curvatura 3D e finalmente à torção geométrica 3D. Em todos os gráficos estas variáveis estão representadas em função da coordenada vertical. Através do método ora proposto, detectamos as regiões da coluna onde aparecem as curvaturas e torções geométricas 3D. Também mostramos que o método desenvolvido permite quantificar, com boa sensibilidade, as deformidades da coluna vertebral, como por exemplo: lordoses, cifoses e escolioses. Os resultados obtidos mostraram uma boa correlação com os do diagnóstico clínico / Abstract: This paper aims at presenting a method for quantitative and tridimensional analysis of the spinal column in a static position. The method utilizes stereoscopic photographic registers, image measurement in digitalized table and data analysis using software developed in order to accelerate the reconstruction procedures and supply quantitative results in the format of graphs representing the 3D curvatures and geometrical torsions of the spinal column. The 3D reconstruction of the anatomic points, marked on the skin over the spinous processes, was developed by Brenzikofer (1991, 1993). The mathematical analysis of 3D curvature and torsion of the anatomic points is obtained through an adjustment of the parametric polynomial least square fit. This method was applied to three voluntary subjects who, before having their photographic registers taken, were submitted to a clinical posture evaluation. A total of twenty anatomic points were marked with contrasting adhesive disks. The subjects were in a static and upright position. The points of reference went from the occipital basis until the spinous process of the fourth lumbar vertebra. The results are presented in six graphs for each subject. Two graphs represent the polynomial fit of the projection of the spinal column curves in the sagittaland frontal plane. Two other graphs represent the bidimensional curvatures in the same planes. One graph represents the 3D curvature and the last one represents the geometric 3D torsion. In alI these graphs the variables are represented in function of the vertical coordinate. This method successfully detected in which areas of the spinal column 3D curvatures and geometrical torsions occur. It also enables the user to quantify, with accuracy, spinal column deformities such as, lordosis, kyphosis, and scoliosis. There is a positive correlation between the results of the proposed method and the clinical diagnosis / Mestrado / Mestre em Educação Física

[EN] Classically, the study of the contact with hyperplanes and hyperspheres has been realized by using the family of height and distance squared functions. On the first part of the thesis, we analyze the Taylor expansion of the exponential map up to order three of a submanifold $M$ immersed in $\r n.$ Our main goal is to show its usefulness for the description of special contacts of the submanifolds with geometrical models. As we analyze the contacts of high order, the complexity of the calculations increases. In this work, through the Taylor expansion of the exponential map, we characterize the geometry of order higher than $3$ in terms of invariants of the immersion, so that the effective computations in specific cases become more affordable. It allows also to get new geometric insights. On the second part of the thesis, we introduce the concept of critical point of a smooth map between submanifolds. If we consider a differentiable $k$-dimensional manifold $M$ immersed in $\r{k+n},$ we know that its focal set can also be interpreted as the image of the critical points of the {\it normal map} $\nu(m,u): NM\to \r{k+n}$ defined by $\nu(m,u)=\pi_N(m,u)+ u,$ for $m\in M$ and $u\in N_mM,$ where $\pi_N:NM\to M$ denotes the normal bundle. In the same way, the parabolic set of a differential submanifold is given through the analysis of the singularities of the height functions over the submanifold. If we consider a differentiable $k$-dimensional manifold $M$ immersed in $\r{k+n},$ we know that its parabolic set can also be interpreted as the image of the critical points of the {\it generalized Gauss map} $\psi(m,u): NM\to \r{k+n}$ defined by $\psi(m,u)= u,$ for $u\in N_mM.$ Finally, we characterize the asymptotic directions as the tangent set of a $k$-dimensional manifold $M$ immersed in $\r{k+n}$ throughout the study of the singularities of the tangent map $\Omega(m,y): TM\to \r{k+n}$ defined by $\Omega(m,y)=\pi(m,y)+y,$ for $y\in T_mM,$ where $\pi:TM\to M$ denotes the tangent bundle. We describe first the focal set and its geometrical relation to the Veronese of curvature for $k$-dimensional immersions in $\r{k+n}.$ Then we define the $r$-critical points of a differential map $f:H \to K$ between two differential manifolds and characterize the $2$ and $3$-critical points of the normal map and generalized Gauss map. The number of these critical points at $m\in M$ may depend on the degeneration of the curvature ellipse and we calculate those numbers in the particular case that $M$ is an immersed surface in $\r{4}$ for the normal map and $\r{5}$ for the generalized Gauss map. / [ES] En general, el estudio del contacto con hiperplanos e hiperesferas se ha llevado a cabo usando la familia de funciones altura y la función distancia al cuadrado. En la primera parte de la tesis analizamos el desarrollo de Taylor de la aplicación exponencial hasta orden 3 de una subvariedad $M$ inmersa en $\r n.$ Nuestro principal objetivo es mostrar su utilidad en el estudio de contactos especiales de subvariedades con modelos geométricos. A medida que analizamos los contactos de orden mayor, la complejidad de las cuentas aumenta. En este trabajo, a través del desarrollo de Taylor de la aplicación exponencial, caracterizamos la geometría de orden mayor que $3$ en términos de invariantes geométricos de la inmersión, por lo que el trabajo con las cuentas en casos especiales se convierte en más manejable. Esto nos permite también obtener nuevos resultados geométricos. En la segunda parte de la tesis se introduce el concepto de punto crítico de una aplicación regular entre subvariedades. Si consideramos una variedad diferenciable $M$ de dimensión $k$ e inmersa en $\r{k+n},$ sabemos que su conjunto focal puede ser interpretado como la imagen de los puntos críticos de la {\it aplicación normal} $\nu(m,u): NM\to \r{k+n}$ definida por $\nu(m,u)=\pi_N(m,u)+ u,$ para $m\in M$ y $u\in N_mM,$ donde $\pi_N:NM\to M$ denota el fibrado normal. De la misma manera, el conjunto parabólico de una subvariedad diferencial viene dado por el análisis de las singularidades de la función altura sobre la subvariedad. Si consideramos una subvariedad $M$ de dimensión $k$ e inmersa en $\r{k+n},$ sabemos que su conjunto parabólico puede ser interpretado como la imagen de los puntos críticos de la {\it aplicación generalizada de Gauss} $\psi(m,u): NM\to \r{k+n}$ definida por $\psi(m,u)= u,$ donde $u\in N_mM.$ Finalmente, caracterizamos las direcciones asintóticas como el conjunto de direcciones del tangente de una subvariedad $M$ de dimensión $k$ e inmersa en $\r{k+n}$ a través del estudio de las singularidades de la aplicación tangente $\Omega(m,y): TM\to \r{k+n}$ definida por $\Omega(m,y)=\pi(m,y)+y,$ para $y\in T_mM,$ donde $\pi:TM\to M$ denota el fibrado tangente. Describimos primero el conjunto focal y su relación geométrica con la Veronese de curvatura para una variedad $k$ dimensional inmersa en $\r{k+n}.$ Entonces, definimos los puntos $r$-críticos de una aplicación $f:H \to K$ entre dos subvariedades y caracterizamos los puntos $2$ y $3$ críticos de la aplicación normal y la aplicación generalizada de Gauss. El número de estos puntos críticos en $m\in M$ depende de la degeneración de la elipse de curvatura y calculamos ese número en el caso particular de una superficie inmersa en $\r{4}$ para la aplicación normal y $\r{5}$ para la aplicación generalizada de Gauss. / [CAT] En general, l'estudi del contacte amb hiperplans i hiperesferes s'ha dut a terme utilitzant la família de funcions altura i la funció distància al quadrat. A la primera part de la tesi analitzem el desenvolupament de Taylor de l'aplicació exponencial fins a ordre 3 d'una subvarietat $M$ immersa en $\r n.$ El nostre principal objectiu és mostrar la seua utilitat en l'estudi de contactes especials de subvarietats amb models geomètrics. A mesura que analitzem els contactes d'ordre major, la complexitat dels comptes augmenta. En aquest treball, a través del desenvolupament de Taylor de l'aplicació exponencial, caracteritzem la geometria d'ordre major que $ 3 $ en termes d'invariants geomètrics de la immersió, de manera que el treball amb els comptes en casos especials es converteix en més manejable. Això ens permet també obtenir nous resultats geomètrics. A la segona part de la tesi s'introdueix el concepte de punt crític d'una aplicació regular entre subvarietats. Si considerem una varietat diferenciable $ M $ de dimensió $ k $ i immersa en $ \r {k + n}, $ sabem que el seu conjunt focal pot ser interpretat com la imatge dels punts crítics de la {\it aplicació normal} $ \nu (m, u): NM \to \r {k + n} $ definida per $ \nu (m, u) = \pi_N (m, u) + o, $ per $ m \in M $ i $ u \in N_mM, $ on $ \pi_N: NM \to M $ denota el fibrat normal. De la mateixa manera, el conjunt parabòlic d'una subvarietat diferencial ve donat per l'anàlisi de les singularitats de la funció altura sobre la subvarietat. Si considerem una subvarietat $ M $ de dimensió $ k $ i immersa en $ \r {k + n}, $ sabem que el seu conjunt parabòlic pot ser interpretat com la imatge dels punts crítics de la {\it aplicació generalitzada de Gauss} $ \psi (m, u): NM \to \r{k + n} $ definida per $ \psi (m, u) = u, $ on $ u \in N_mM. $ Finalment, caracteritzem les direccions asimptòtiques com el conjunt de direccions del tangent d'una subvarietat $ M $ de dimensió $ k $ i immersa en $ \r{k + n} $ a través de l'estudi de les singularitats de l'aplicació tangent $ \Omega (m, y): TM \to \r {k + n} $ definida per $ \Omega (m, y) = \pi (m, y) + y, $ per $ y \in T_mM, $ on $ \pi: TM \to M $ denota el fibrat tangent. Descrivim primer el conjunt focal i la seva relació geomètrica amb la Veronese de curvatura per a una varietat $ k $ dimensional immersa en $ \r{k + n}. $ Llavors, definim els punts $ r $-crítics d'una aplicació $ f: H \to K $ entre dues subvarietats i caracteritzem els punts $ 2 $ i $ 3 $ crítics de l'aplicació normal i l'aplicació generalitzada de Gauss. El nombre d'aquests punts crítics en $ m \in M $ depèn de la degeneració de l'el·lipse de curvatura i calculem aquest nombre en el cas particular d'una superfície immersa en $ \r{4} $ per a l'aplicació normal i $ \r{5} $ per a l'aplicació generalitzada de Gauss. / García Monera, M. (2015). r-critical points and Taylor expansion of the exponential map, for smooth immersions in Rk+n [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/50935 / TESIS

The purpose of this thesis is design of a six-cylinder engine arrangement with given main parameters (bore, stroke, etc.), powertrain design, possibilities of firing order, balancing inertia forces and its moments, in case of need, balancing shaft design and calculation of torsion vibrations.

Diploma thesis is trying to analyze crank mechanism of a gas V-sixteen engine. Kinematics and balance crank mechanism are analyzed, dynamic model parameters are dermined, natural frequency of the torsional system are calculated, coupling parameters are designed and torsional problem with attached electric generator is analyzed.

The purpose of this thesis is design of a crank mechanism for diesel aircraft engine. Next then appropriately balance crank mechanism, strength tests and calculation of crankshaft torsional vibration. Developing of drawings documentation of crankshaft.

The primary objective of this thesis was to design a crankshaft according to given parameters. In this case the thesis also contains the balancing of inertia forces and its moments, modal analysis and calculation of torsion vibrations. The last chapter includes a calculation of the safety factor by using a Finite Element Method.

Martin Lhota Formula Student Front Chassis Part Design DW, IAE, 2011, 75 pp, 62 pics The aim of the thesis is to suggest a suitable configuration of Formula Student Car’s front part of a frame according to current rules of SAE organization in the Formula Student competition. In this proposal low weight, manufacturability and sufficient torsion rigidity were preferred, whereas previously suggested solutions were reflected. At first there is presented a list of important SAE rules for the construction of front part followed by a short recherché of development of the constructional solution of frames and frames suitable for Formula Students car. Secondly there is described process during frame construction design and its computational model for the analysis which simulates torsion with the support of MKP system. Gained results and some parameters of the frame are compared with similar version of the frame construction which was suggested and made for the first Formula Student Car of our University. Moreover, there is also presented summary of suggested frame and also recommendation with possible alternatives for the next development.