Analysis and Design of Robustness for Surface Modifications in Plasma Spraying Processes
| Autor: | Ming-der Jean, 簡明德 |
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| Rok vydání: | 2007 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 96 This paper presents the application of the surface response methodology, fuzzy logic and fractional factorial experiment at developing a robust partially stabilized zirconia (PSZ) coatings in plasma spraying processes. In this study, a two-step experimental design with a nonlinear regression model is proposed. First, with the application of analysis of variance, significant factors are screened. Appropriately choosing control factors while constructing response functions helps to develop a robust process. In addition, a nonlinear response surface function is designed to explore the space of the process and model prediction is improved by additional data transformation. Secondly, a fuzzy logic is used to explore a functional relationship for determining the efficiency of each parameter design for plasma sprayings. This smoothes the progress of developing not only a proper relation between yielded and process variables, but also an optimal parameter setting that produce desirable values of responses. These response surfaces can help in the prediction of the spraying coatings at any area of the experimental domain. In this study, the microstructural feature of the coatings is addressed. The relationships between the microstructure of the coatings and their properties are discussed. The experimental results show that using a quadric response model and fuzzy logic with proposed two-step design strategy is a simple, effective, and efficient approach. In the optimized model, several response plots were generated to examine parameter effects on the profile. Optimization of the PSZ performances in a plasma spray process has been performed. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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