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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.
1

Modeling evolution of anisotropy and hardening for sheet metals

Choi, Yangwook, January 2003 (has links)
Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xvii, 155 p. : ill. (some col.). Advisors: June K. Lee, Robert H. Wagoner, and Mark E. Walter, Dept. of Mechanical Engineering. Includes bibliographical references (p. 141-147).
2

Diagnosis of sheet metal forming processes based on thermal energy distribution: 3D reconstruction.

January 2005 (has links)
Ng Yiu Ming. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 110-114). / Abstracts in English and Chinese. / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Diagnosis concept based on thermal energy distribution --- p.6 / Chapter 1.1.1 --- A cup drawing example --- p.8 / Chapter 1.2 --- Need for 3D infrared thermal distribution measurement --- p.10 / Chapter 1.3 --- Outline of the Thesis --- p.11 / Chapter 2. --- Approach --- p.15 / Chapter 2.1 --- Similarity and extreme temperature analysis --- p.15 / Chapter 2.2 --- Thermodynamics for FEA in sheet metal stamping --- p.17 / Chapter 2.3 --- Acquisition of 3D thermal distribution --- p.20 / Chapter 3. --- Implementation of the Diagnosis System --- p.23 / Chapter 3.1 --- Thermograph acquisition --- p.23 / Chapter 3.2 --- Diagnosis system setup --- p.24 / Chapter 3.3 --- Perspective camera model --- p.25 / Chapter 3.4 --- System calibration --- p.27 / Chapter 3.4.1 --- LEDs calibration board --- p.27 / Chapter 3.4.2 --- Net-and-board calibration box --- p.29 / Chapter 3.5 --- Reconstruction algorithm --- p.33 / Chapter 3.6 --- Summary --- p.37 / Chapter 4. --- Consistency from Different Viewpoints --- p.38 / Chapter 4.1 --- Summary --- p.42 / Chapter 5. --- Visual Reconstruction of Objects --- p.44 / Chapter 5.1 --- Visual camera calibration --- p.45 / Chapter 5.2 --- Results --- p.49 / Chapter 5.2.1 --- "Cartoon model ""SiuSun""" --- p.49 / Chapter 5.2.2 --- Stamping disc --- p.51 / Chapter 5.3 --- Summary --- p.53 / Chapter 6. --- Thermal Distribution Reconstruction of Stamping Workpieces --- p.54 / Chapter 6.1 --- Infrared camera calibration --- p.54 / Chapter 6.2 --- Results --- p.57 / Chapter 6.2.1 --- Air conditioner cap --- p.57 / Chapter 6.2.2 --- Deep drawing cup --- p.59 / Chapter 6.2.3 --- Stamping cylinder from KS Factory --- p.61 / Chapter 6.3 --- Summary --- p.65 / Chapter 7. --- Infrared Camera on a Robotic Arm --- p.66 / Chapter 7.1 --- Robotic arm system setup --- p.67 / Chapter 7.2 --- System calibration --- p.68 / Chapter 7.3 --- Results --- p.77 / Chapter 7.3.1 --- Image sequence from horizontal viewpoints --- p.77 / Chapter 7.3.2 --- Image sequence from inclined viewpoints --- p.80 / Chapter 7.3.3 --- Image sequence from arbitrary viewpoints --- p.83 / Chapter 7.4 --- Comparison of the three different viewpoints --- p.85 / Chapter 7.5 --- Summary --- p.87 / Chapter 8. --- Compensation of Temperature Fade-out Problem --- p.88 / Chapter 8.1 --- Causes of temperature fade-out --- p.88 / Chapter 8.2 --- Solutions --- p.90 / Chapter 8.3 --- Summary --- p.91 / Chapter 9. --- Other Applications --- p.92 / Chapter 9.1 --- Automotive industry --- p.92 / Chapter 9.1.1 --- Background --- p.93 / Chapter 9.1.2 --- Experiment and result --- p.94 / Chapter 9.2 --- General heat transfer analysis --- p.97 / Chapter 9.3 --- Summary --- p.98 / Chapter 10. --- Conclusions --- p.99 / Chapter 10.1 --- Summary --- p.99 / Chapter 10.2 --- Future work --- p.104 / Chapter A. --- Transformation Matrices of the System --- p.106 / Bibliography --- p.110
3

A new sheet metal forming system based on incremental punching. / CUHK electronic theses & dissertations collection

January 2010 (has links)
In order to ensure the desirable performance of the machine, dynamic analysis of the machine is necessary. The analysis is conducted by the mean of computer simulation in consideration of applying a large impulsive force. This study validates the machine stability and accuracy. / In order to verify the new mechanics model, numerical and experimental studies are conducted using the new incremental punching system. The final shape and thickness distributions of parts are compared to verify the mechanics model. It is found that the model prediction fits the experiment result well. Forming parameters are also investigated. / In this research, a new incremental forming system based on incremental punching is designed and built. The system consists of a 3-axes CNC platform, a high speed hydraulic cylinder with a hemispherical forming tool, and a PC-based CNC control system. The hydraulic system provides the forming force to deform the sheet metal with constant stokes, while the CNC system positions the part. When forming a part, the forming tool punches the sheet metal along the given contour of the part punch by punch; when one layer of the part is completed, the forming tool moves down to the next layer; and the process is finished till all layers are completed. The CNC control system works with standard NC code, and hence, is easy to use. / ISMF uses a small generic tool to apply a sequence of operations along the given path to deform the sheet incrementally. These small deformations accumulate to form the final shape of the part. As a result, different parts can be made by the same setup. Despite of some 30 years of research and development, however, ISMF technology is still premature for industrial applications due to the following reasons: The accuracy of the part is limited; the surface roughness is poor; and the productivity is low. This motivates the presented research. / One of the keys to successful application of sheet metal forming is to be able to predict the deformation and the strain/stress of the part incurred during the forming process. Because of the complexity of the ISMF process, it is not possible to derive an analytical method. The alternative is to use Finite Element Analysis (FEA). However, based on our experience, it takes about one week to solve a simple case. A mechanics model is therefore developed. It consists of two steps. The first step is to computer the final shape: the initial geometric surface is obtained using the punch positions; then using the minimum energy principle, the virtual forces drive the nodes of geometric surface to their lowest energy positions, which gives the final shape of the forming part. The second step is to predict the strain and stress distributions. This is done using the inverse Finite Element Modeling (FEM). An in-house computer software is developed using MATLABRTM. / Stamping is one of the most commonly used manufacturing processes. Everyday, millions of parts are formed by this process. The conventional stamping is to form a part in one or several operations with a press machine and a set/sets of dies. It is very efficient but is not cost effective for small batch production parts and prototypes as the dies are expensive and time consuming to make. Recently, with the increasing demands for low-volume and customer-made products, a die-less forming method, Incremental Sheet Metal Forming (ISMF), has become one of the leading R&D topics in the industry. / To evaluate the capability of the presented ISMF process, the formability is studied by the means of theory and experiment. A modified M-K model is proposed for predicting the forming limit of the formed part which is undergoing a very complicated strain path. The maximum forming angle is also investigated by experiments. / Luo, Yuanxin. / Adviser: Ruxu Du. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 121-133). / 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 Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
4

Investigation of interlayer burr formation in the drilling of stacked aluminum sheets

Hellstern, Cody. January 2009 (has links)
Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2009. / Committee Member: Rhett Mayor; Committee Member: Shreyes Melkote; Committee Member: Steven Danyluk. Part of the SMARTech Electronic Thesis and Dissertation Collection.
5

Evaluering van dieptrekbaarheid van aluminiumplaat

08 September 2015 (has links)
M.Ing. / To investigate the effect of plastic anisotropy in 1200H14 Aluminium sheet, simulations of the Swift Cupping Test were carried out using the finite element program ABAQUS. Anisotropy was built into all simulations based on the plastic strain ratio which was calculated from tensile tests on specimen cut in three directions in the plane of the sheet. Deep drawing tests were carried out using a punch and die sub-assembly as described by the Swift Cupping Test. Holder loads were kept constant while the punch load and displacement were recorded. Punch force-punch displacement curve and the formation of ears were compared with experimental results.
6

Sheet metal forming using rapid prototyped tooling

Park, Young-Bin 05 1900 (has links)
No description available.
7

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.
8

Production techniques in contemporary sheetmetal activities : a creative project

Phillips, Richard Irving January 1977 (has links)
This creative project has explored the possibility of establishing a field of technical literature which bridges the gap between processes books and engineering texts. The project, by setting an example, has presented a format which may easily be followed by other writers in the field.The project specifically deals with eleven contemporary sheetmetal forming techniques. In addition, the handbook presents an overall view of production planning, quality control, and standardization.
9

Design for uncertainties of sheet metal forming process

Zhang, Wenfeng, January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 187-192).
10

An approach to automate the synthesis of sheet metal parts

Patel, Jay K., January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

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