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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.
31

Sheet metal forming using rapid prototyped tooling

Park, Young-Bin 05 1900 (has links)
No description available.
32

On Extrusion Forging and Extrusion Rolling of Thin Metal Sheets

Feng, Zhujian 02 October 2013 (has links)
Sheet metal surfaces with pin-fin features have potential fluid and thermal applications. Extrusion forging process and extrusion rolling process can be used to create such surface features on sheet metals. Extrusion forging process is a metal forming process that combines extrusion and forging into one operation. In extrusion forging, the pin-fin surface feature is created by compressing the work-piece using a punch with designed cavities. Experiments and numerical analysis were conducted to investigate the effects of tooling geometries, material properties, work-piece thickness, thickness reduction ratio and friction on the deformation behavior of sheet metals. It was found that increasing fillet radius of the orifice results in decrease in compressive force and boss height. As the negative draft angle increases, the compressive force and boss height decrease. Higher yield strength and higher friction lead to higher compressive force. The boss height is not significantly affected by the friction between the tooling and the work-piece. Due to limitation in force capacity, it may not be feasible to apply extrusion forging technique to generate surface features on large surface area. As such, the extrusion rolling process is proposed. In extrusion rolling, the pin-fin feature is created by compressing the strip using a pair of rolls. The upper roll is manufactured with surface cavities. Finite element method are employed to investigate the effects of rolling speed, thickness reduction ratio, roll diameter and front tension force on the deformation behavior of metal strip. It was found that the rolling speed has little influence on the roll force and boss height. The front tension force has little effect on the average pressure and boss height. Increase the roll diameter results in in roll force increase. This research investigated the effect of parameters on the deformation behavior during the extrusion forging and extrusion rolling processes. The research generated the knowledge needed for design and manufacture of micro/meso surface features on thin metal sheet. Moreover, this thesis presents a novel bulk forming process on metal sheets, which can have significant impacts in industrial practice.
33

A variable radius roll test for measuring the adhesion of paint systems to deformable steel substrates

Jinks, Damien. January 2003 (has links)
Thesis (Ph.D.)--University of Wollongong, 2003. / Typescript. Bibliography: leaf 288-292.
34

Analysis of rib-plate response to external loading

Zhao, Jia-Xiang. January 1989 (has links)
Thesis (M.S.)--Ohio University, March, 1989. / Title from PDF t.p.
35

A study on laser forming processes with finite element analysis : a thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Mechanical Engineering at the University of Canterbury, Christchurch, New Zealand /

Jung, Hyung-Chul. January 1900 (has links)
Thesis (Ph. D.)--University of Canterbury, 2006. / Typescript (photocopy). "April 2006." Includes bibliographical references (p. [271]-279). Also available via the World Wide Web.
36

Friction hydro pillar riveting process of Ti-6AI-4V titanium sheet

Tsikayi, Davies Shamiso January 2015 (has links)
Mechanical fasteners are used extensively in the joining of two or more metal plates or sheets. Riveted joints have been the joints of choice mainly for the Aerospace Industry. However for this research, Friction Hydro Pillar Processing has been used to develop and characterise a new riveting technique termed Friction Hydro Pillar Riveting (FHPR). Two overlapping 3.17 mm Ti-6Al-4V sheets were joined together using Ø6 mm rivet which was friction processed. This research has focussed on the initial development of Friction Hydro Pillar Riveting thereby establishing a basic understanding of the influences of main process parameters, rotational speed and axial force - and also joint configurations. The results showed that with a decrease in the bottom hole chamfer angle, there was resulting overall increase in the rivet joint pull off strength. From the best performing joint configuration in pull off tests, shear tests were conducted whilst a blind hole FHPR joint was also done and tested in pull off and shear strength. The shear test fracture surfaces exhibited ductile failure. The microstructure of the joints was thus evaluated. From parent material, heat affected zone and to weld zone there was a variation in the microstructure analysed. The hardness profiles showed increased hardness in the weld zone which partly explained the shear results. The hardness increase was mainly due to grain refinement in the weld zone by the Friction Hydro Pillar Riveting process.
37

Electromagnetically assisted sheet metal stamping

Shang, Jianhui 22 September 2006 (has links)
No description available.
38

Effects of Strain Path Changes on Damage Evolution and Sheet Metal Formability

Zaman, Tasneem January 2008 (has links)
The concept of the Forming Limit Diagram (FLD) has proved to be useful for representing conditions for the onset of sheet necking, and is now a standard tool for characterizing materials in terms of their overall forming behavior. In this study, the M-K approach, in conjunction with Gurson model, is used to calculate FLDs. The influences of mechanical properties, including strain hardening, strain rate sensitivity, as well as the void nucleation, growth and coalescence, on the FLDs are examined. Most sheet metals undergo multiple deformation modes (strain paths) when being formed into complex manufacturing parts. When the strain path is changed in the deformation processing of metal, it's work-hardening and flow strength differs from the monotonic deformation characteristics. As a consequence, sheet metal formability is very sensitive to strain path changes. In this study, the hardening behavior and damage evolution under non-proportional loading paths are investigated. The effect of strain path change on FLDs is studied in detail. FLDs are conventionally constructed in strain space and are very sensitive to strain path changes. Alternatively, many researchers represented formability based on the state of stress rather than the state of strain. They constructed a Forming Limit Stress Diagram (FLSD) by plotting the calculated principal stresses at necking. It was concluded that FLSDs were almost path-independent. In this work, the FLSD has been constructed under non-proportional loading conditions to assess its path dependency when damage effect is included. / Thesis / Master of Applied Science (MASc)
39

Conduction modeling and laser beam propagation through plasma in sheet metal laser welding

Tanriver, Ugur 01 October 2000 (has links)
No description available.
40

Expanded forming limit testing for sheet forming processes

Shouler, Daniel Reginald January 2011 (has links)
No description available.

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