• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 251
  • 51
  • 35
  • 33
  • 20
  • 20
  • 20
  • 20
  • 20
  • 20
  • 16
  • 10
  • 6
  • 5
  • 4
  • Tagged with
  • 540
  • 315
  • 77
  • 69
  • 57
  • 50
  • 46
  • 45
  • 41
  • 39
  • 39
  • 39
  • 31
  • 30
  • 30
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

EFFECT OF VOID VOLUME ON THE FRICTION AND RHEOLOGY OF CONCENTRATED SLURRIES.

Lezzar, Ahmed. January 1983 (has links)
No description available.
192

Aksesuarų komplektas "Deformacijos" / Accessory kit "Deformations"

Barzinskaitė, Marta 02 September 2010 (has links)
Visais laikais žmonės savo kūnui skyrė ypatingą dėmesį, noras gražiai atrodyti vertė kentėti skausmą ir nepatogumą. Kad kūnas įgautų trokštamą siluetą, dažnai buvo naudojama pagalbinė priemonė - korsetas. Korsetas ilgus metus buvo privaloma kostiumo dalis, tik keitėsi forma, medžiagos iš kurių jis buvo gaminamas, bei dėvėjimo būdas. 1900m. korsetas išgyveno didžiausio populiarumo metą, tačiau ir šiomis dienomis aukštoji mada neišsiverčia be šios aprangos detalės. Istoriniai šaltiniai liudija, kad korsetu kūnas buvo dažniau žalojamas, nei dailinamas. Kūrybinio darbo tikslas sukurti ir įgyvendinti aksesuarų komplektą, kuris perteiktų kūno suvaržymo korsetu idėją, panaudojant netradicinį korseto vaizdą, norint pademonstruoti absurdišką savęs kankinimą dėl mados. Kūrybinio darbo pavadinimas „Deformacijos“, todėl, siekiant perteikti įvardintą temą, ypatingas dėmesys skiriamas paties kūrinio formai ir jo funkcijai, deformuoti natūralų žmogaus kūną. / At all times people gives special attention for theirs bodys, wish to be beautiful makes life uncomfortable and full of pain. To have desire siluet, often was used auxiliary tool – corset. Long time corset was mandatory costume element, only form, background material and wearing way was changed. In 1990 corset was on top of the popularity, even today haute couture fashion can not visualize models without corset. Historic resources testify, that corset ofter damaging body, than retouched. Aim of the creativ work is develop and implement accessory kit, which shows the idea of restraining the body with the unusual corset representation and also it shows absurd body torture for fashion. Title of the creative work is “Deformations”, for this reason special attention is given for item form and function, to deform natural human body.
193

Monitoring cracks in a rotating shaft

Mohamed, Alhade Abdossllam January 2012 (has links)
Condition monitoring of rotating shafts is gaining importance in industry due to the need to increase machine reliability and decrease the possible loss of production due to machine breakdown. In this work, the use of vibration signals for the detection of a crack within a shaft was investigated. The research involved the measurement of vibration signals during laboratory tests on a long rotating shaft rig. The focus of the experimental work was on the effect of cracks on the dynamics and the initiation and growth of cracks in the shaft. Measurements were taken from the shaft system both with simulated cracks (notches) cut at 45° and 90° to the shaft axis and with real propagating cracks initiated by a pre-crack cut. All defects were located at the mid- point along the shaft. The vibration responses and stresses were measured for different depths of crack. The vibration responses of the three different defects were compared using PSDs of the data to identify the change in position and magnitude of the peaks in the spectrum under each defect. Experiments to study the effect of defect depth at different shaft rotation speeds were also carried out. Finally, a shaft with a breathing crack (continuously opening and closing as the shaft rotates) was also studied experimentally, with the crack growing under normal steady state operating conditions. After completing the experiment work, the shaft was broken and the type of fracture studied. The results for both simulated and actual crack growth showed that vibration frequencies decreased as a crack progressed, indicating the possibility of using the vibration signal for crack detection. A significant relationship was found between the stage of crack growth and the vibration results. A finite element (FE) model was constructed to explore the relationship between the natural frequencies and crack depth and position along the shaft and to explain and validate the results of the experimental work. The FE model showed similar trends to the experimental results and also allowed the effect of different crack positions to be explored. The PSD data was fed into an artificial neural network after a feature extraction procedure was applied to significantly reduce the quantity of data whilst at the same time retaining the salient information. Such an approach results in a considerably reduced training time for the network due to the reduced complexity. The proposed scheme was shown to successfully identify the different defect levels. This method greatly enhances the capacity of an automated diagnostic process by linking increased capability in signal analysis to the predictive capability of the artificial neural network.
194

Aktuální sborník kreslených tělesných anomálií / The Contemporary Compillation of Body Anomalies Drawings

Jochimová, Aneta January 2012 (has links)
In my practical diploma thesis, I’m extending on its theoretical part named Androgyn / The mysterium of completeness, particularly the chapter Bodily construction of the androgynous character (transformations of the body and character, metamorphosis and other deformations). I will explore the theme as a complex using multiple media I was using throughout my studies. These are: A. fragmented drawings, that will eventually be the basis for a graphical novel. In my drawings, I’ll capture the appearance and detailed transformation of bizarre anomalies of an animated body. Another output will be B. an installation of drawings in space. Using monumental digitally printed wallpapers, I’ll create a installation in space, that will represent the “cabinet of body representation”. In my thesis, I’ll also use C. a program for generating the shape of human body out of its basic parameters – I’ll create “real” bodies I’ll use later on in my graphical collection. The last part will be D. photographs of details of human body enlarged to a billboard size.
195

Grandes deformações e anisotropia por tensores de mapeamento aplicados a problemas de materiais compostos e na conformação de metais / Finite deformations and anisotropy by mapping tensors applied to composites and sheet metal forming

Rubert, José Benaque 21 November 1997 (has links)
Este trabalho tem por objetivo demonstrar a viabilidade do emprego da teoria de interação de substâncias no contínuo para a análise de compostos multifásicos, sendo possível considerar-se substâncias anisótropas através de sua representação via uma formulação isótropa equivalente. No campo teórico, referente à anisotropia via formulação isótropa equivalente, deduzem-se tensores de mapeamento de tensões e deformações para o espaço fictício na configuração deformada, adequados às análises com grandes deformações. Os modelos de materiais compostos e de anisotropia propostos, foram implementados no âmbito de um código de cálculo para análise dinâmica explícita com grandes deformações. Entre as aplicações do programa destacam-se o estudo de problemas de conformação de lâminas metálicas e de compostos multifásicos e a possibilidade de analisar compostos de matriz frágil reforçada por fibras curtas, considerando-se uma função simples de dano elasto-plástico. Os exemplos executados mostram boa concordância dos resultados obtidos neste trabalho com aqueles obtidos por outros autores e com alguns resultados experimentais existentes. / The aim of this work is to valuate the performance of the theory of interacting substances in the continuum (role of mixtures) applied to composites including anisotropic substances which are modeled by an isotropic equivalent formulation. In the theoretical field, with respect to the anisotropy consideration by an equivalent isotropic formulation on the deformed configuration, convenient mapping tensors for stresses and strains in the fictitious space are deduced and applied to large deformation problems. The proposed models of anisotropy and composites were implemented in an explicit code for dynamic analysis with large deformations. The code is applied to the solution of sheet metal forming processes and multiphase composites including an analysis of a brittle matrix composite reinforced by short fibers by a simple elastoplastic damage model. The numerical results of the chosen examples are in good agreement with those suggested in some references or with some reported experiments.
196

ANALYSIS OF PROCESS INDUCED SHAPE DEFORMATIONS AND RESIDUAL STRESSES IN COMPOSITE PARTS DURING CURE

Ameya Sanjay Patil (6613250) 11 June 2019 (has links)
<div>Process induced dimensional changes in composite parts has been the topic of interest for many researchers. The residual stresses that are induced in composite laminates during curing process while the laminate is in contact with the process tool often lead to dimensional variations such as spring-in of angles and warpage of flat panels. The traditional trial-and-error approach can work for simple geometries, but composite parts with complex shapes require more sophisticated models. When composite laminates are subjected to thermal stresses, such as the heating and cooling processes during curing, they can become distorted as the in-plane and the throughthickness</div><div>coffcients of thermal expansion are different, as well as chemical shrinkage of the resin, usually cause spring-in. Deformed components can cause problems during</div><div>assembly, which significantly increases production costs and affects performance. This thesis focuses on predicting these shape deformations using software simulation of composite manufacturing and curing. Various factors such as resin shrinkage, degrees of cure, difference between through thickness coefficient of thermal expansion of the composite laminate are taken into the consideration. A cure kinetic model is presented which illustrates the matrix behavior during cure. The results obtained using the software then were compared with the experimental values of spring-in from the available literature. The accuracy of ACCS package was validated in this study. Analyzing the effects of various parameters of it was estimated that 3D part simulation is an effective and cost and time saving method to predict final shape of the composite part.</div>
197

Interactive simulation of multi-material deformable models. / CUHK electronic theses & dissertations collection

January 2007 (has links)
Based on the expression specifying the deformation of a multi-component object, a component-based condensation method is developed. This further reduces the size of the matrix to be inverted from the total number of unknown displacements to the number of unknown displacements with changing boundary condition. To speed up the construction of matrices, a maximal matrix technology is proposed. By categorizing the changes in boundary conditions, three fast update strategies on matrix inverse are introduced. Based on the maximal matrix technology and the matrix inverse update strategy, eight easily-formed characteristic matrices are defined to enhance the computation speed further. / In this thesis, an algorithm is developed for simulating the deformation of multiple objects with different material properties using the boundary element method. By tessellating the surface of a geometric model into elements, classifying all the element nodes into different groups with different attributes, and partitioning the stiffness matrix into several sub-matrices according to these attributes, a compact expression about the unknown variables is deduced. In this expression, the dimension of the system matrix has been effectively reduced compared with the traditional method. This expression shows that the deformation of a multi-component object can be simulated in a way similar to that of a single-component object. / Research on the real-time deformation of elastic models has captured wide attention and gained considerable achievement in the past two decades. Most related works focus on developing efficient ways to simulate the behavior of a single-component elastic object. However, objects are usually made up of multiple components with different material properties in practice. It is thus essential to develop efficient techniques for modeling objects which are composed of more than one material. / To make the proposed accelerated algorithm more applicable, a method for simulating the deformation of multi-component models with non-matching interfaces is developed. By applying the interpolation and extrapolation methods, the displacement data can be transferred between non-conforming interfaces. With the application of the energy conservation principle, a relationship between the internal forces on different surfaces can also be established. Together with the force equilibrium conditions and displacement compatibility conditions over the common faces of objects, the deformation of models composed of multi-material components with non-matching interfaces can be simulated. During the application of the linear interpolation method, when the mesh densities on the interfaces of the neighboring components are not the same, unexpected phenomena arise in the simulation process because of this disparity. A traction super-imposition method is adopted to enforce the force constraints on the interface. Experiments showed that this approach produces the correct results. / Zhou, Aifang. / "August 2007." / Adviser: Keh Chuen Hui. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 1299. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 144-155). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.
198

Prediction of spring-back in thin sheet of aluminium alloy

Nguyen, Vu Thua, 1965- January 2003 (has links)
Abstract not available
199

Packing of particles during softening and melting process.

Zheng, Xiao-Qin, Materials Science & Engineering, Faculty of Science, UNSW January 2007 (has links)
Softening deformation of iron ore in the form of sinter, pellet, and lump ore in the cohesive zone of an ironmaking blast furnace is an important phenomenon that has a significant effect on gas permeability and consequently blast furnace production efficiency. The macroscopic softening deformation behavior of the bed and the microscopic deformation behavior of the individual particles in the packed bed are investigated in this study using wax balls to simulate the fused layer behavior of the cohesive zone. The effects of softening temperature, load pressure, and bed composition (mono - single melting particles, including pure or blend particles vs binary ??? two different melting point particles) on softening deformation are examined. The principal findings of this study are: 1. At low softening temperatures, an increase in load pressure increases the deformation rate almost linearly. 2. At higher softening temperatures, an increase in load pressure dramatically increases the deformation rate, and after a certain time there is no more significant change in deformation rate. 3. The bed deformation rate of a mono bed is much greater than that of a binary one. 4. In a binary system, the softening deformation rate increases almost proportionally with the increase in the amount of lower melting point wax balls. 5. In a mono system with blend particles, the content of the lower melting point material has a more significant effect on overall bed deformation than the higher melting point one. 6. The macro softening deformation of the bed behaves the theory of creep deformation. 7. A mathematical model for predicting bed porosity change due to softening deformation based on creep deformation theory has been developed. 8. Increase in load pressure also reduces the peak contact face number of the distribution curves, and this is more prominent with higher porosity values. 9. The contribution of contact face number to bed porosity reduction is more pronounced in a mono system than in a binary system. 10. The porosity reduction in a binary bed is more due to the contact face area increase, presumably of the lower melting point particles. 11. The mono system has a single peak contact face number distribution pattern while the binary system exhibits a bimodal distribution pattern once the higher melting point material starts to deform. 12. In a binary system, an increase in deformation condition severity tends to reduce the contact face number of the higher melting point material without having to increase the contact face number of the lower melting point material accordingly to achieve a given porosity.
200

Prediction of deformations in post-tensioned prestressed suspended slabs in tall buildings.

Vincent, Thomas J. January 2009 (has links)
The research presented in this thesis focuses on the accuracy of predicting deflections and cambers in partially prestressed suspended slabs. Precision in predicting this behaviour accurately is complex due to the large number of variables which affect the behaviour of suspended prestressed slabs. This level of complexity is particularly relevant for post tensioned slabs due to the numerous on site construction steps. Many of the variables are hard to determine accurately due to their tendency to be unique for each construction site. Variables such as ambient temperatures, concrete material properties, stressing times, applied loads, loading times, prop movement and humidity are all examples of these properties. Hence, when predicting the behaviour of post tensioned suspended slabs of a multi storey building there always remains a degree of uncertainty. The research presented in this thesis addresses crucial areas of this topic and ultimately aims to supply reinforced concrete designers and constructors with additional confidence when predicting this behaviour. The requirement for this project surfaced during the design stages of 151 Pirie, a multistorey building constructed in Adelaide, Australia. The design project for 151 Pirie was particularly complex due to a very ambitious construction timeline. The strict construction timeline was imposed due to the contractual agreement of early occupancy of the top three floors (of a 9 storey building). The client purchasing the top floors required functioning office space within a matter of months. This contract created a construction priority of erecting the bare structural requirements up to and including the top three floors in the shortest possible time. Fittings and services to the top three floors was then the secondary priority. Fitting and services to the lower floors (which would usually be achieved before the upper floors) would be performed at a later date. Excessive deflection limits of the slabs due to the accelerated construction were a major concern for the client. The effect on the deformation performance due to the accelerated construction was difficult to predict for the designer. Therefore, this project was born to help supply confidence to the designer and concrete supplier for this construction scenario. This research project was designed to assist in the close monitoring and recording of the construction process of 151 Pirie. Due to the nature of data collection, data from this construction site would be limited in its benefits for the current construction. However, the data obtained would be vital for future projects by providing a log of onsite slab performance data as well as explanations of delays or other general outcomes with the construction process. Therefore, the aim of this research is to present the issues that were faced, the methods used to overcome these issues as well as displaying the vast amounts of site specific data documented within this project for future reference. In this research a wide range of concrete material properties were collected and monitored closely on site as well as in the laboratory. The experimental testing created large detailed database of concrete material properties as well as other relevant factors such as surveyed deflections and construction timing. Concrete material properties were the primary focus of this research due to their direct effect on member performance. The database was sufficiently large to allow a meaningful statistical data analysis to be performed on the compressive strength (f’[subscript]c), modulus of elasticity (E[subscript]c) and tensile strength (f’[subscript] t) of the concrete samples. This analysis supplied a detailed understanding of the statistical relationship between different concrete material properties. A Monte Carlo simulation was performed, with multiple deflection and camber models, to create a statistical distribution of predicted deflections and cambers from the statistical distribution of concrete material properties. This statistical output is then critically analysed and compared to the surveyed data. Proposed improvements to the process of predicting deflections and cambers have been outlined. These improvements have then been utilised in the construction of a finite element style program. Finally, the multiple predictions of column strip and mid panel deformation are compared to the short term surveyed deflections. It is summarised that the improvements suggested and implemented in the finite style analysis yield results with a higher degree of accuracy. The accuracy and benefits of the suggested improvements has been justified and proven by the application of multiple examples and a parametric study. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1366459 / Thesis (M.Eng.Sc.) -- University of Adelaide, School of Civil, Environmental and Mining Engineering, 2009

Page generated in 0.1662 seconds