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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

Identification of cladding-structure interaction in highrise buildings using parameter estimation methods

Meyyappa, Murugappan 05 1900 (has links)
No description available.
2

Sensing and control of Nd:YAG laser cladding process

Salehi, Dariush, ds_salehi@yahoo.com January 2005 (has links)
Surface engineering provides solutions to wear and corrosion degradation of engineering components. Laser cladding is a surfacing process used to produce wear and corrosion resistant surfaces by covering a particular part of the substrate with another material that has superior properties, producing a fusion bond between the two materials with minimal dilution of the clad layer by the substrate. The advantages of laser cladding compared to conventional techniques include low and controllable heat input into the workpiece, a high cooling rate, great processing flexibility, low distortion due to the low heat input to the workpiece and minimal post-treatment. The main processing parameters of laser cladding include laser power, laser spot size, processing speed, and powder feed rate. Within an optimized operational window, all these variables have some effect on the temperature of the clad interaction zone. The laser cladding technique is very complicated because it involves metallurgical and physical phenomena, such as laser beam-materials interaction, heat transfer between the clad and the substrate, and the interdiffusion of the clad and the substrate materials. Laser cladding is currently an open-loop process, relying on the skills of the operator and requiring dedication to specialty to make it successful. Unless the required expertise is provided, attempts to make the process successful will be futile. The objective in conducting the project was to investigate and develop prototype sensors to monitor and control Nd:YAG laser cladding process. Through a LabVIEW software based monitoring program, real-time process monitoring of optical emissions in the form of light and heat radiation was carried out, and correlated with the properties of the produced clad layers. During various experiments, single- and multiple-track laser cladding trials were performed. The responses of such sensors to the selected conditions were examined and an in depth analysis of detected heat and optical radiation signals was carried out. The results of these experiments showed the ability of such sensors to recognize changes in process parameters, and detected defects on layer surfaces along with the presence of oxides. A multi-function closed-loop laser power and CNC motion table feed rate control interface based on a LabVIEW platform has been designed and built, which is capable of accepting and interpreting sensors� data and adjusting accordingly the laser power and CNC motion table feed rate to produce sound clad layers. The developed dual control strategy utilized in this study forms a relatively inexpensive and less-complicated system that allows end-users to achieve lower failure rates during laser cladding (within its own limitations) and, therefore, through successful concurrent control of melt pool temperature and motion table feed rate provide better productivity and quality in the experimentally produced clad layers.
3

Development of energy dissipating cladding connections for passive control of building seismic response

Pinelli, Jean-Paul 12 1900 (has links)
No description available.
4

Characterizing the influence of process variables in laser cladding Al-20WT%Si onto an Aluminium Substrate

Von Wielligh, Louis George Unknown Date (has links)
The research investigated the application of continuous coaxial laser cladding by powder injection as a surface treatment or coating process. The investigation aimed to establish the relationship between a change in the main laser cladding process variables and the geometry and characteristics of an Al-20wt-Si single pass clad layer formed on an Al 1370-F substrate using a Nd:YAG laser. The main process variables considered were: laser power, laser scanning velocity and the powder feed rate. The relationship between a change in the main laser cladding process variables and the geometry and characteristics of the clad layer was established by statistically analysing the variation in the process response with a change in the main laser cladding process variables. The process variables were varied based on a full-factorial, experimentally optimized test matrix. The clad geometry which is mainly defined by: the clad height, width, clad aspect ratio, depth of alloy penetration, and the clad root angle/wetting angle was investigated. In addition to the clad geometry several clad characteristics were investigated such as the dilution of the clad layer in the substrate material, the Vickers microhardness and microstructure of the clad crosssection, the powder efficiency of the process and the amount of visible defects. The study successfully established the relationship between the main laser cladding process variables and the clad geometry and characteristics. The secondary objective of establishing a suitable processing window by considering the relationship mentioned above was only partially met since it is believed that further refinement of the experimental cladding test setup and therefore also the experimental variable test levels is required.
5

On-line inspection and thermal properties comparison for laser deposition process

Yang, Yu, January 2007 (has links) (PDF)
Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed December 6, 2007) Includes bibliographical references.
6

Seismic energy dissipation of buildings using engineered cladding systems

Nguyen, Quan Viet, January 2009 (has links)
Thesis (M.S.C.E.)--University of Massachusetts Amherst, 2009. / Open access. Includes bibliographical references (p. 87-89).
7

Laser cladding surface treatment for enhancement of mechanical properties /

Yang, Wen Fu. January 1900 (has links)
Thesis (MTech (Mechanical Engineering))--Peninsula Technikon, 2003. / Word processed copy. Summary in English. Includes bibliographical references (leaves 99-105). Also available online.
8

Influence of nonstructural cladding on dynamic properties and performance of highrise buildings

Palsson, Hafsteinn 12 1900 (has links)
No description available.
9

Three dimensional nonlinear dynamic response of an RC structure with advanced cladding

El-Gazairly, Loai F. 05 1900 (has links)
No description available.
10

Stiffening effect of cladding on light-weight structures /

Lawrence, S. J. January 1972 (has links) (PDF)
Thesis (M.Eng.Sc.)--University of Adelaide, Dept. of Civil Engineering, 1974. / "January 1972." Includes bibliographical references.

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