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Remanufacturing of worn blades with various defects normally requires processes such as scanning, regenerating a geometrical reference model, additive manufacturing (AM) through laser cladding, adaptive machining and polishing and quality inspection. Unlike the manufacturing process of a new part, the most difficult problem for remanufacturing such a complex surface part is that the reference model adaptive to the worn part is no longer available or useful. The worn parts may suffer from geometrical deformation, distortion and other defects because of the effects of harsh operating conditions, thereby making their original computer aided design (CAD) models inadequate for the repair process. This paper aims to regenerate the geometric models for the worn parts, which is a key issue for implementing AM to build up the parts and adaptive machining to reform the parts. Unlike straight blades with similar cross sections, the tip geometry of the worn tip of a twist blade needs to be regenerated by a different method.

This paper proposes a surface extension algorithm for the reconstruction of a twist blade tip through the extremum parameterization of a B-spline basis function. Based on the cross sections of the scanned worn blade model, the given control points and knot vectors are firstly reconstructed into a B-spline curve D. After the extremum of each control point is calculated by extremum parameterization of a B-spline basis function, the unknown control points are calculated by substituting the extremum into the curve D. Once all control points are determined, the B-spline surface of the worn blade tip can be regenerated. Finally, the extension algorithm is implemented and validated with several examples.

The proposed algorithm was implemented and verified through the exampled blades. Through the extension algorithm, the tip geometry of the worn tip of a twist blade can be regenerated. This method solved a key problem for the repair of a twist blade tip. It provides an appropriate reference model for repairing worn blade tips through AM to build up the blade tip and adaptive machining/polishing processes to reform the blade geometry.

The extension errors for different repair models are compared and analyzed. The authors found that there are several factors affecting the accuracy of the regenerated model. When the cross-section interval and the extension length are set properly, the restoration accuracy for the blade tip can be improved, which is acceptable for the repairing.

The lack of a reference geometric model for worn blades is a significant problem when implementing blade repair through AM and adaptive machining processes. Because the geometric reference model is unavailable for the repair process, reconstruction of the geometry of a worn blade tip is the first crucial step. The authors proposed a surface extension algorithm for the reconstruction of a twist blade tip. Through the implementation of the proposed algorithm, the blade tip model can be regenerated.

Remanufacturing of worn blades with various defects is highly demeaned for the aerospace enterprises considering sustainable development. Unlike straight blades, repair of twist blades encountered a very difficult problem because the geometric reference model is unavailable for the repair processes. This paper proposed a different method to generate the reference model for the repair of a twist blade tip. With this model, repair of twist blades can be implemented through AM to build up the blade tip and adaptive machining to subtract the extra material.

The authors proposed a surface extension algorithm to reconstruct the geometric model for repair of twist blades.

Layered manufacturing with curved layers is a recently proposed rapid prototyping (RP) strategy for the manufacture of curved, thin and shell-type parts and the repair of worn surfaces, etc. The present investigation indicates another possible application area. In case of flat-layered RP of computer-aided design models having randomly located, small-dimensioned but critical surface features, adaptive slicing is resorted to. Large number of thin slices have to be employed to preserve the critical features. In contrast, a considerably lower number of curved thin slices would be required to preserve such surface features in case of RP with curved layers.

The method of preservation of critical features by RP with curved layers is formulated and demonstrated for two clusters of critical features on the surface of a part. A minimum number of such curved layers is identified by application of genetic algorithms (GAs) in case of a simple example. GA evolves the shape of the curved layer passing through the lower cluster so as to make a curved layer pass through the upper cluster of critical features.

In the example part, a 21 per cent reduction in the number of layers is achieved by the application of adaptive curved layers over adaptive straight layers.

The novelty of the concept is the proposed use of curved layered RP with adaptive slicing for the preservation of critical features in final prototyped part. This methodology, applied to part with two distinct clusters, leads to reduced number of layers compared to that obtained in flat-layered RP.

This work aims to estimate the unknown surface temperature distribution on the boundary of a heat conducting solid body from temperature measurements taken from another boundary where convective boundary condition is also known. A steady inverse heat conduction problem is described for an arbitrary three‐dimensional body. A gradient‐based inverse method combined with B‐spline function specification is employed to solve the inverse problem. The validity of the proposed method is verified with computational results.

This ongoing research revolute the conventional clothing design process by garment constructions in truly three dimensions rather than in two dimensions by ways of pattern design. The aim of the research is to develop a computer‐assisted clothing design tool in complete three dimensions. It would provide the garment designers the capabilities of 3D basal garment creation, restyling, and static fitting analysis when wearing on a digital mannequin. The kernel of the design environment and the mathematical formulas used in garment creation are described, results and implementations will be presented later in part II of this paper.

In this paper, a mannequin‐based garment design and restyling tools in three dimensions is proposed. The tools are based on mathematical formulas which provide an intuitive way of computer‐aided garment design.

Free style creation on clothes is performed by the provided tools and its formulas behind. Feature‐based mannequin model is initially constructed by its features interpolation. The crucial girths on garment, for instances, collar girth and sleeve girth are generated from the neck girth and the armhole girth, respectively. Based on the feature girths on the mannequin, garment surface is “radial grown” from the digital mannequin. B‐spline surface, loft surface, and sweep surface are used to build blouse, sleeve, and collar for creation and restyling.

Basal garment is initially “grown” from the computer mannequin model, which means, size grading no longer becomes extra work. 3D restyling tool is then invoked to conduct versatile designs by exhibiting designers' imagination space. Static fitting analysis is easily performed by the corresponding features on the mannequin.

In this paper, a new three dimensions method in clothing design for clothes style creation and restyling in three dimensions on a digital mannequin model is proposed. In this research, a truly 3D garment design tool is developed in order to break through currently paper draft design concept.

Non‐linear transformation of freeform curves and surfaces is useful in computer‐aided design and computer graphics. It is highly desirable that the original and transformed curves or surfaces are defined using the same representation. But freeform curves and surfaces defined by control points are invariant only under affine transformations, and not so under non‐linear transformations. This paper develops a method that can perform non‐linear transformations of freeform curves to specific accuracies, while retaining the same representation. It involves first applying the transformation to the control points and then modifying them so that the resulting curve and the exact transformed curve are equal at a specific number of points, which is the number of control points. Refinement to the approximation is made by increasing the number of control points. A method for measuring the maximum positional error has been implemented and this is used to facilitate an algorithm for automatic refinement. Extension of the method for surfaces is also given.

A powerful 3‐D system has been developed for on‐line 3‐D human measurement and reconstruction that interferes with a SQL Server database for virtual wearer trials in global retailing. In this research, 3‐D body profiles have been captured and analysed using an on‐line image measurement and processing system developed in this research and then stored in the database system. A parametric geometric human model has been devised with an effective search algorithm that utilises body measurements obtained on‐line or retrieved from the database. A SQL server database system has been constructed with user friendly interfaces which enables users to collect, manage and analyse all related information including human body images.

With the rapid advancement of computer information technology, the traditional clothing industry has stridden towards automation and digitization that drive the growth of electronic commerce and line retailing. The purpose of this paper is to propose an approach on 3D upper body modelling based on the body measurements extracted by non-contact anthropometry.

Based on the frontal and side images of the human body, the body sizes were extracted through silhouette extraction, identification of landmarks and girth prediction. The generation rules of 15 characteristic cross-sectional curves were established using a method “feature points – inserted points – feature curves – basic surface – mannequin”. The feature points of each position were determined at each curve, such as the side neck point, front neck point, shoulder point, bust point, and bust root point and so on to get the cross-sections, and then some feature points were inserted at the curves according to the widths and depths to establish the calculative models. For example, there are 18 points distributed at the bust cross-sectional curve to determine the shape.

The final mannequin could describe the basic characteristics of a human body, and the shape of the feature curves could also fit the body type to provide basis for the future research on automatic pattern generation.

This study can realize the 3D virtual modelling of female upper body and the automatic generation of the individualized apparel patterns based on the frontal and side images.

The aim of this paper is to explore a method of predicting the amount of personalized bra cup dart in the 3D virtual environment for supporting the made‐to‐measure research of the optimum fitted brassiere pattern design.

Very useful enhanced FFD (free‐form‐deformation) techniques used in both computer animation and geometric modeling were skillfully transplanted to the female breast model deformation. Meanwhile, on the basis of 3D scan and surface modeling technologies, the realization approach of the abstract female breast model library focusing on the individual variations of shapes and sizes was presented. Then according to the principle of isometric area and flabellate segments, the personalized bra cup dart quantity and its distributive information were provided by 3D‐2D transformation.

The paper finds that personalized female breast shapes and various aesthetic breast forms sculpted by different bras could be interactively simulated. Accordingly, the amount of corresponding individual bra cup dart and its distributive information were provided. The cup darts were mainly distributed below the bust line. Moreover, dart shapes were curvy.

The principles of virtual breast library construction and 3D‐2D transformation are also suitable for other parts of the human body such as buttocks, abdomen and, etc. for intimate apparel research.

The method of predicting the personalized bra cup dart quantity based on the 3D virtual breast model library was delivered for the first time. The novel findings provided an important guideline for designers to improve the well‐fitted bra pattern design technique. Furthermore, it would reduce the manufacturing cost without keeping physical dummies.

Automatic trajectory generation for spray painting is highly desirable for today’s automotive manufacturing. Generating paint gun trajectories for free‐form surfaces to satisfy paint thickness requirements is still highly challenging due to the complex geometry of free‐form surfaces. In this paper, a CAD‐guided paint gun trajectory generation system for free‐form surfaces has been developed. The system utilizes the CAD information of a free‐form surface to be painted and a paint gun model to generate a paint gun trajectory to satisfy the paint thickness requirements. A paint thickness verification method is also provided to verify the generated trajectories. The simulation results have shown that the trajectory generation system achieves satisfactory performance. This trajectory generation system can also be applied to generate trajectories for many other CAD‐guided robot trajectory planning applications.

Gives a bibliographical review of the finite element meshing and remeshing from the theoretical as well as practical points of view. Topics such as adaptive techniques for meshing and remeshing, parallel processing in the finite element modelling, etc. are also included. The bibliography at the end of this paper contains 1,727 references to papers, conference proceedings and theses/dissertations dealing with presented subjects that were published between 1990 and 2001.