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  • 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.
131

Návrh výroby konzoly / Production concept of bracket

Kašpar, Jaroslav January 2019 (has links)
The thesis deals with the production concept of the bracket for fixing the drying frame. The component is made of 11 343 steel. The semi-finished product is galvanized sheet with 2 mm thickness. With regard to the required quality of the component and the yearly production quantity (40,000 pieces), a new production technology was chosen based on a literary study by means of conventional shearing in a tool, followed by bending on a press brake. For the selected technologies, technological calculations and a cutting tool were designed, which are dealt with in the drawing documentation. The work also includes technical-economic evalua-tion of the proposed production method.
132

Technologie pro ohýbání nesymetrického ocelového profilu / Technology for bending unsymetric profile of steel

Walach, Lukáš January 2008 (has links)
The present thesis deals with the determination of procedural parameters of given bending profile including the calculation of spring-back, especially the bending force. It compares the differences and the benefits of two different technologies of producing a blank, the simple bending and the technology of rolling. The technological process suggested involves technical-economical evaluation, supplemented with the drawing documentation.
133

Výroba třmenu sdruženým nástrojem / Stirrup manufacturing by compound tool

Brodský, Zdeněk January 2009 (has links)
The master´s thesis deals with drawing compound tool for production of stirrup. Stirrup is made from steel 17 240 and his thickness is 1,5 mm. The number of production is 400 000 pieces. After completion of constructional calculations was determined eccentric press LEN 40 C and was designed tool. The work is completed by drawing documentation of the compound tool. In the work is performed economic evaluation too. Present technology (blanking, bending) is compare here with new technology- compound tool. Compound tool is profitable, because time and money are saving.
134

Technologie výroby součásti tvářením / Technology of production parts by forming

Litochlebová, Soňa January 2010 (has links)
The thesis solves the efficient production of the sheetmetal cover. The new technological procedure will save two manufacturing operations deep drawing. The deep drawing of the cylindrical vessel with a flange and its following calibration in accordance with the design documentation was choosed. The last stage of the deep drawing is the construcion of the circular cut-out and its bending. By doing so the final shape of the cover will be reached.
135

Technologie ohýbání ocelového profilu / Bending technology profile of steel

Kameník, Tomáš January 2013 (has links)
KAMENÍK Tomáš: Bending technology profile of steel The project has been elaborated within the master's of studies of the subject M-STG manufacturing technology and it presents the lay-out of the bending technology profile of steel from the material S235JRG2. The bend is made by the bending and the press tools. The press tools and the bending profile were suggested on the bases of the literature study of technology bending. In consideration of the calculated bending power and the dimension profile will be made profile on the hydraulic press CYS 320 ( the manufacturer ŠMERAL Brno a.s.). At the end of the the thesis there are performed calculations of the technical and economic evaluation for the machine press and the bending .
136

Výroba součásti garážového automatického zamykání sdruženým nástrojem / Manufacturing of part of garage automatic door lock by compound tool

Vaverka, Ivo January 2014 (has links)
This master’s thesis created in the master studies of the M-STG Manufacturing technology is focused on the manufacturing of a part of a garage automatic door lock by a compound tool. The part is made of a rolled steel coil of the S275JR material with the thickness of 2 mm. The number of parts manufactured per year equals to 600 000. Literary studies deals with the issues of cutting and bending. On the basis of the most advantageous manufacturing variant and technological calculations the compound tool is designed. As a working machine the eccentric press LEK 160 is chosen. In the economical evaluation part, the calculations to finding out when the manufactory becomes profitable are carried out.
137

Výroba výztuže dveřního zamykání sdruženým nástrojem / The reinforcement door locking manufacturing by compound tool

Drápala, Miroslav January 2014 (has links)
The submitted project was created in the engineering studies of M-STG Machinery technologies and it is focused on problematics of production of reinforcement door locking. Component will be manufactured by cutting and bending technologies and used material is aluminium alloy EN AW-3103. As a manufacturing stock is used roll of sheet. Manufacturing series is 400 000 pieces a year. Literary study was created according to the mentioned technologies. After the control calculation was proccesed, the compound tool was designed. As a working machine was selected accentric press SMERAL LE 250/40, where the compound tool will be clamped.
138

Bending Analysis of Nonlocal Functionally Graded Beams

Garbin, F., Garbin, F., Levano, A., Arciniega, R. 07 February 2020 (has links)
In this paper, we study the nonlocal linear bending behavior of functionally graded beams subjected to distributed loads. A finite element formulation for an improved first-order shear deformation theory for beams with five independent variables is proposed. The formulation takes into consideration 3D constitutive equations. Eringen's nonlocal differential model is used to rewrite the nonlocal stress resultants in terms of displacements. The finite element formulation is derived by means of the principle of virtual work. High-order nodal-spectral interpolation functions were utilized to approximate the field variables, which minimizes the locking problem. Numerical results and comparisons of the present formulation with those found in the literature for typical benchmark problems involving nonlocal beams are found to be satisfactory and show the validity of the developed finite element model.
139

Understanding Mechanical Properties of Bio-filaments through Curvature

Wisanpitayakorn, Pattipong 16 August 2019 (has links)
Cells are dynamic systems that generate and respond to forces through the complex interplay between biochemical and mechanical regulations. Since cellular processes often happen at the molecular level and are challenging to be observed under in vivo conditions due to limitations in optical microscopy, multiple analysis tools have been developed to gain insight into those processes. One of the ways to characterize these mechanical properties is by measuring their persistence length, the average length over which filaments stay straight. There are several approaches in the literature for measuring the persistence length of the filaments, including Fourier analysis of images obtained using fluorescence microscopy. Here, we show how curvature can be used to quantify local deformations of cell shape and cellular components. We develop a novel technique, called curvature analysis, to measure the stiffness of bio-filaments from fluorescent images. We test our predictions with Monte-Carlo generated filaments. We also apply our approach to microtubules and actin filaments obtained from in vitro gliding assay experiments with high densities of non-functional motors. The presented curvature analysis is significantly more accurate compared to existing approaches for small data sets. To study the effect of motors on filament deformations and velocities observed in gliding assays with functional and non-functional motors, we developed Langevin dynamics simulations of on glass and lipid surfaces. We found that generally the gliding velocity increases with an increase in motor density and a decrease in diffusion coefficient, and that motor density and diffusion coefficient have no clear effect on filament curvatures, except at a very low diffusion coefficients. Finally, we provide an ImageJ plugin to make curvature and persistence length measurements more accessible to everyone.
140

Transverse and Longitudinal Bending of Segmental Concrete Box Girder Bridges

Maguire, Marcus J. 30 July 2013 (has links)
Post-tensioned segmental concrete box girders have been in use in the United States since the early 1970s. This unique bridge system uses post-tensioning to connect many smaller concrete bridge segments into very efficient long span bridges. However, because of the slender components, localized transverse bending becomes more critical when compared to more conventional bridge types. Bridge owners are finding that ratings for standard loads and permit trucks are often controlled by the transverse behavior of the girders near concentrated wheel loads. The popular analysis methods used today range from two dimensional frame models to three dimensional finite element models of the entire bridge. Currently, engineers must make sound engineering judgments on limited available information, while balancing safety and economy. To quantify and understand longitudinal and transverse behavior, the results from three live load tests of single cell segmental concrete box girder bridges are presented. Each bridge was instrumented with longitudinal and transverse strain sensors on at least two cross sections as well as rotation and deflection sensors, when possible. Two dimensional transverse frame models and three dimensional shell models were compared to the test results for each subject bridge. The two dimensional frame analyses using the common bottom web pin and roller boundary conditions provide mean absolute percent error in excess of 250%. Conversely, the newly introduced boundary conditions using pin supports at the top and bottom of each web was shown to reduce mean absolute percent error to 82%, which is on the same order of magnitude as longitudinal beamline analysis. The three dimensional shell models were insensitive to several changes including mesh fineness, number of spans modeled, and support conditions. Using uniform surface loading, the transverse modeling procedure was shown to provide significantly more accurate results than the common two dimensional frame models. A faster and more convenient analysis method using a program generated, structure specific, influence surface was also outlined. This method produced similar results when compared to the uniform surface loading method, while allowing additional automation for easier load application. / Ph. D.

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