UM E-Theses Collection (澳門大學電子學位論文庫)


Surface deformation on composite patches by constrained morphing

English Abstract

This thesis proposes a novel freeform surface deformation method for all freeform surfaces regardless of their mathematical representation. This method is particularly designed for automatic matching of freeform surface. Shorter development time of a new product allows manufactures to response quickly to various demands from market and saving time costs. A product platform employing reverse engineering and feature-based product family database can support mass customization, which aims at developing, producing, marketing, and delivering affordable goods and services with sufficient variety and customization that nearly everyone finds exactly what he/she wants by employing mass production processes. Customization can be supported by “re-usage of features” from product family database. Re-usage not only can save the development time of a new product model, but also reuse the “design intention”, like shapes and functions. However, features must be well defined so that features of the same kind are compatible to each other. Reverse engineering is a design approach that transforms a physical model into a digital model through a series of procedures. The physical object often consists of freeform surfaces that is difficult to be described exactly on draft paper. However, reverse engineering can transform a physical model prepared by a stylist into digital one. Designer can define features in the procedures of reverse engineering in order to facilitate feature re-usage. When features are reused to construct a new product model, they must be classified as either base feature, where deformation is not necessary and working feature, where deformation is to be imposed on. This thesis aims at deforming freeform surface globally and uniformly. Repositioning of control points of a freeform surface has an obvious geometric meaning in shape design. Designers often modify surface by control points. Hence, a control-point based deformation method is proposed, regardless of type of freeform surfaces. Designers can avoid handling mathematics related to freeform surfaces. The proposed method triangulates control net and treats the triangulated control net as a spatial spring network. Control point constraints of a freeform surface can be imposed on the spring network to achieve a global and uniform deformation for preservation of smoothness and similarity. The deformation adopts the technique used for finite element analysis of space truss. Solution is determined by minimum total potential energy of the spring network. The proposed method is tested by seven examples, from simple one to industry application of shoelast design. However, it can be foreseen that this method can be extended any application where freeform surface deformation is required.

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Lo, Kin Man


Faculty of Science and Technology


Department of Electromechanical Engineering




Mechanical engineering

Engineering design


Yang, Zhi Xin

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1/F Zone C
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