Background: Accurate assessment of left ventricular (LV) systolic function in chronic severe primary mitral regurgitation (MR) is important as the aim is to consider surgical repair prior to the onset of irreversible LV dysfunction. However this can be difficult to judge as conventional measures of LV function (such as ejection fraction, EF) may remain normal despite impaired LV contractility due to the increased preload of the condition. Advanced echocardiographic techniques, including deformation imaging, appear promising as they are less load dependent. As the earliest symptoms in severe MR are usually exertional, this study aimed to assess markers of LV deformation on exercise in patients with normal resting EF in order to try and identify the earliest signs of LV decompensation.Methods: Transthoracic echocardiography was carried out at rest and on submaximal supine exercise in asymptomatic patients with moderate to severe chronic primary MR and matched controls. Conventional contractile reserve (CR) as measured by EF change on exercise was used to subdivide patients into those with preserved (CR+) and abnormal (CR-) LV function. Myocardial strain and twist were assessed using the speckle tracking technique.Results: MR patients failed to show the normal enhancement in systolic twist on exercise. The onset and peak of untwisting were delayed in MR at rest and normalised on exercise in CR+ but not in CR-. Abnormalities in twist on exercise worsened with increasing resting preload. Longitudinal strain tended to increase normally on exercise in CR+ but not in CR-. Systolic longitudinal strain rate correlated with twist at rest and on exercise, whereas diastolic strain rate correlated with the timing of untwisting on exercise.Conclusion: Abnormalities in myocardial deformation are seen at rest and on exercise in patients with severe MR, particularly in those with decompensated LV function. This may contribute to the development of functional impairment with progressive disease.

The thesis presents a manufacturing technology proposition for a terminal pin made of copper according to ČSN 42 3001.1 located in combution engine distributor in a series of 320 000 pcs. Based on a literature study, 3 versions of operation sequence were proposed, 2 of them with concern for lowest number of operations possible and the third, chosen one, was designed so the strain and therefore mechanical properties were equal in whole volume of final part. Forming force and work were calculated, utilizing the Johnson-Cook material model. Overall calculated forming force was 64,5 kN and total work for one part 189 J. Subsequently technical drawings of die and punch for the second operation of forward extrusion of shaft were processed along with workspace assembly drawing for the Šmeral TPM 5 machine, which was chosen for the fabrication. Economic evaluation set the costs for one part manufactured 0,09 Eur and equilibrium point, after which the production generates profit, located at 170 000 pcs produced.

Orientador: Inácio Maria Dal Fabbro / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-22T14:06:58Z (GMT). No. of bitstreams: 1 Cardoso_KelenCristiane_M.pdf: 10447047 bytes, checksum: bd1de8c6f17c3f3f8e755c78ecee3801 (MD5) Previous issue date: 2013 / Resumo: A determinação de tensões e deformações é amplamente empregada na engenharia. Métodos clássicos de extensometria elétrica, extensometria mecânica e simulações por elementos finitos são úteis e permitem qualificar e quantificar a distribuição de carga em elementos de extrutura. Estudos fotoelásticos vêm ganhando cada vez mais espaço, pois facilitam a determinação e permitem a visualização da distribuição de tensões no espécimen em estudo de maneira rápida e confiável. As técnicas de moiré de sombra e projeção são os métodos mais comumente utilizados devido principalmente à simplicidade e rapidez de medição, tornando-os objeto de frequentes estudos em vários tipos de aplicações. A vantagem de se utilizar as técnicas de moiré está associada à simplicidade dos equipamentos necessários, simplicidade de aquisição e processamento de imagens, além de ser adequadas ao estudo de corpos de geometria simples ou complexa. A proposta deste trabalho se identifica em qualificar e quantificar as distribuições de deformação e tensão em uma mola membrana, como elemento de máquina de geometria complexa pela aplicação de técnica de moiré. Para este trabalho foi escolhido à mola membrana como elemento de máquina de geometria complexa, sendo um elemento de papel muito importante na montagem do conjunto de embreagem, pois o desalinhamento das linguetas pode resultar em trepidação ou vibração no pedal, gerando dificuldade de acionamento do mecanismo, podendo gerar também deformações dos componentes, e com isso desgaste prematuro do sistema em pauta. O deslocamento da mola membrana no acionamento da embreagem promove uma alteração na distribuição de tensão e deformação em seu perfil assim como nos componentes associados à mola, e o desalinhamento das linguetas faz com que essa distribuição não seja uniforme. A técnica de moiré de sombra pode auxiliar a simulação para determinar a deformação, a tensão bem como a distribuição de pressão sobre a superfície da mola membrana. A simulação computacional por elementos finitos e a técnica de extensometria com strain gauges, será utilizado como base de comparação entre os resultados obtidos por moiré de forma a proporcionar uma validação da técnica em estudo em elementos mecânicos de geometria não simples / Abstract: A diaphragm spring was chosen as a machine element of complex geometry, which integrates the clutch assembly. The tabs misalignment may result in vibrations transmitted to the clutch system, as well as difficulties in driving the pedal and can also generate components deformation and thus premature wearing of the whole clutch system. The displacement of the diaphragm spring during clutch driving promotes alterations on the stress and strain distribution on its profile as well as on the components associated to the spring, and tabs misalignment turns this distribution not uniform. The determination of stress and strain is widely used in engineering. Classical methods as electrical strain gage, mechanical gage and finite element simulations are useful to the qualification and quantification of load distribution in the specimens. Photoelastic techniques are gaining space, because it facilitates the stress and strain distribution determination, allowing clear visualization of the undergoing phenomena based on a quick and reliable experimentation. The shadow moiré and projection moiré techniques are the most commonly used methods primarily due to its measurement simplicity and quickness which supports frequent studies and proposed applications. The advantage of using moiré techniques is associated to the requirement of simple experimental setup for image acquisition and processing as well as its application to bodies of simple or complex geometry. The purpose of this study was to apply a moiré technique to obtain the stress and strain qualification and quantification on a spring membrane taken as a machine component of complex geometry. The shadow moiré technique can assist the simulation to determine the strain and stress distribution on diaphragm spring surface. The computer simulation by finite element technique and strain gauges, were used as the basis of comparison between the results obtained by the moiré method to validate the application of the proposed optical method to study of mechanical elements of complex geometry / Mestrado / Maquinas Agricolas / Mestra em Engenharia Agrícola

A high-order hybrid discontinuous Galerkin finite element method (DG-FEM) is developed for multi-layered curved panels having large deformation and finite strain. The kinematics of the multi-layered shells is presented at first. The Jacobian matrix and its determinant are also calculated. The weak form of the DG-FEM is next presented. In this case, the discontinuous basis functions can be employed for the displacement basis functions. The implementation details of the nonlinear FEM are next presented. Then, the Consistent Orthogonal Basis Function Space is developed. Given the boundary conditions and structure configurations, there will be a unique basis function space, such that the mass matrix is an accurate diagonal matrix. Moreover, the Consistent Orthogonal Basis Functions are very similar to mode shape functions. Based on the DG-FEM, three dedicated finite elements are developed for the multi-layered pipes, curved stiffeners and multi-layered stiffened hydrofoils. The kinematics of these three structures are presented. The smooth configuration is also obtained, which is very important for the buckling analysis with large deformation and finite strain. Finally, five problems are solved, including sandwich plates, 2-D multi-layered pipes, 3-D multi-layered pipes, stiffened plates and stiffened multi-layered hydrofoils. Material and geometric nonlinearities are both considered. The results are verified by other papers' results or ANSYS. / Master of Science

<p>Stanje Zemljine kore određeno je istovremenim i suprotstavljenim uticajem<br />endodinamičkih i egzodinamičkih procesa. Povr&scaron;inski slojevi omotača<br />Zemljine kore su u stalnom pokretu pod dejstvom uticaja, kao &scaron;to su<br />promena nivoa podzemnih voda, tektonske pojave, klizi&scaron;ta itd. Značajne<br />deformacije mogu se javiti kao posledica niza regionalnih i lokalnih<br />naponskih stanja, posebno u graničnim zonama litosfernih ploča, gde se<br />akumuliraju naponi i javljaju nelinearne innterseizmičke deformacije. U<br />disertaciji je prikazano istraživanje pomeranja Zemljine kore regionalnog<br />karaktera sa geodetskog aspekta, na osnovu ponovljenih opažanja metodom<br />satelitskog pozicioniranja, čime je dat doprinos multidisciplinarnom<br />razumevanju stanja Zemljine kore.</p> / <p>The state of the Earth&rsquo;s crust is determined by the simultaneous and opposed<br />influence of the endodynamic and exodynamic processes. The surface layers of<br />the Earth&rsquo;s crust envelope are in the state of permanent moving due to divers<br />influences, such as the level variation of underground waters, tectonic<br />phenomena, landslides, etc. Significant deformations can arise as a consequence<br />of a number of regional and local strain states, especially in the boundary zones<br />of lithosphere plates where strains are accumulated and non-linear interseismic<br />deformations appear. The subject of the thesis is a study of movements of the<br />Earth&rsquo;s crust of regional character from the aspect of geodesy, on the basis of<br />repeated observations by applying the satellite positioning method. In this way a<br />contribution is given to a multidisciplinary concept of the state of the Earth&rsquo;s crust.</p>

In the simulation of deformations of plates it is well known that we have to use a special treatment of the thickness dependence. Therewith we achieve a reduction of dimension from 3D to 2D. For linear elasticity and small deformations several techniques are well established to handle the reduction of dimension and achieve acceptable numerical results. In the case of large deformations of plates with non-linear material behaviour there exist different problems. For example the analytical integration over the thickness of the plate is not possible due to the non-linearities arising from the material law and the large deformations themselves. There are several possibilities to introduce a hypothesis for the treatment of the plate thickness from the strong Kirchhoff assumption on one hand up to some hierarchical approaches on the other hand.:1. Introduction 2. The 3D-deformation energy 3. Basic differential geometry of shells 4. Kirchhoff assumption and the deformed plate 5. Plate energy and boundary conditions 6. Numerical example

In this thesis a theory for large deformation of plates is presented. Herein aspects of the common 3D-theory for large deformation with the Kirchhoff hypothesis for reducing the dimension from 3D to 2D is combined. Even though the Kirchhoff assumption was developed for small strain and linear material laws, the deformation of thin plates made of isotropic non-linear material was investigated in a numerical experiment. Finally a heavily deformed shell without any change in thickness arises. This way of modeling leads to a two-dimensional strain tensor essentially depending on the first two fundamental forms of the deformed mid surface. Minimizing the resulting deformation energy one ends up with a nonlinear equation system defining the unknown displacement vector U. The aim of this thesis was to apply the incremental Newton technique with a conformal, C^1-continuous finite element discretization. For this the computation of the second derivative of the energy functional is the key difficulty and the most time consuming part of the algorithm. The practicability and fast convergence are demonstrated by different numerical experiments.:1 Introduction 2 The deformation problem in the three-dimensional space 2.1 General differential geometry of deformation in the three-dimensional space 2.2 Equilibrium of forces 2.3 Material laws 2.4 The weak formulation 3 Newton’s method 3.1 The modified Newton algorithm 3.2 Second linearization of the energy functional 4 Differential geometry of shells 4.1 The initial mid surface 4.2 The initial shell 4.3 The plate as an exception of a shell 4.4 Kirchhoff assumption and the deformed shell 4.4.1 Differential geometry of the deformed shell 4.4.2 The Lagrangian strain tensor of the deformed plate 5 Shell energy and boundary conditions 5.1 The resulting Kirchhoff deformation energy 5.2 Boundary conditions 5.3 The resulting weak formulation 6 Newton’s method and implementation 6.1 Newton algorithm 6.2 Finite Element Method (FEM) 6.2.1 Bogner-Fox-Schmidt (BFS) elements 6.2.2 Hsiegh-Clough-Tocher (HCT) elements 6.3 Efficient solution of the linear systems of equation 6.4 Implementation 6.5 Newton’s method and mesh refinement 7 Numerical examples 7.1 Plate deflection 7.1.1 Approximation with FEM using BFS-elements 7.1.2 Approximation with FEM using reduced HCT-elements 7.2 Bending-dominated deformation 7.2.1 Approximation with FEM using BFS-elements 7.2.1.1 1st example: Cylinder 7.2.1.2 2nd example: Cylinder with further rotated edge normals 7.2.1.3 3rd example: Möbiusstrip 7.2.1.4 4th example: Plate with twisted edge 7.2.2 Approximation with FEM using reduced HCT-elements 7.2.2.1 1st example: Partly divided annular octagonal plate 7.2.2.2 2nd example: Divided annulus with rotated edge normals 8 Outlook and open questions Bibliography Notation Theses List of Figures List of Tables