METHOD FOR ESTIMATING GEOMETIC CHARACTERISTICS OF NUMERICAL CONCEPTUAL AIRCRAFT MODELS BASED ON SURFACE ELEMENTS

To estimate the geometric characteristics, especially wet areas and section areas, of three dimensional numerical conceptual aircraft models, a method based on surface elements is proposed. On the premise that numerous surface elements are generated to represent each component surface, a component wet area of the surface is estimated by adding up the areas of such elements that are not covered by any other component surfaces. The elements are also used to get the section polygons of such composite surfaces as the whole aircraft at a given body station, then a section area is approximated with the sum of trapezoidal areas between such sides of polygons that are not covered by any other component and a reference axis. Practical application to a computer aided aircraft conceptual design system shows that the methed is applicable to different kinds of conceptual aircraft models and its precision is satisfying to the conceptual design.

COOPERATIVE DESIGN UNDER CONCURRENT ENGINEERING ENVIRONMENT

This paper outlines a concurrent engineering environment that supports interaction between members of a geographically dispersed multidisciplinary team who is engaged in engineering design activities. Some ideas of engineering design, especially conceptual design are reviewed. A deeper scientific analysis of intelligent design is discussed. A new problem solving strategy and methodologies to implement cooperative design are proposed. Finally, a conceptual model of a blackboard system for accomplishing conceptual design automation is presented. Its fundamental principles, system organization and key implementation techniques are investigated in detail.

AN APPROACH TO FEATURE-BASED PARAMETRIC DESIGN FOR DIE AND MOULD

An approach to feature-based parametric design for die and mould is proposed in this paper.The assembly relationship and parts of the die and mould are described by feature.The dependent relationship of features is described by parent-child operator structure.The feature shape and location can be modified by design parameters.An expert system is used for deriving a geometry of the features which satisfies the given constraints.This approach provides a more natural and convenient method of representing a parametric model of the die and mould.

A FORMAL REPRESENTATION FOR FEATURE-BASED DESIGN

Feature based design has been regarded as a promising approach for CAD/CAM integration.This paper aims to establish a domain independent representation formalism for feature based design in three aspects: formal representation,design process model and design algorithm.The implementing scheme and formal description of feature taxonomy,feature operator,feature model validation and feature transformation are given in the paper.The feature based design process model suited for either sequencial or concurrent engineering is proposed and its application to product structural design and process plan design is presented. Some general design algorithms for developing feature based design system are also addressed.The proposed scheme provides a formal methodology elementary for feature based design system development and operation in a structural way.

心中的高档车

高档豪华车有不同的定位,若是按缸数论,很多人至今认为1988年问世的6缸金翼1500是缸数最多的,其实1912年美国就制造了V型8缸发动机摩托车,1956年意大利MOTOGUZZI的V型8缸500ml发动机则创造了当时摩托车的车速纪录。我在电脑上画的V型12缸2000ml电喷发动机摩托车由于排气管很多,我便给它起了个”大长城——龙须鲸2000”的名字(见图1)。为了使整车便于操纵,龙须鲸的几个缸只有2000ml。

Digital Jacquard Fabric Design in Colorful Mode

Digital image design is one of advanced technique in textile design. The investigation into digital Jacquard textile design in the colorful mode is one form of research in digital Jacquard fabric design, which aimed at expanding past and present jacquard design and production methods towards innovative ends. In this paper, the design principles and design methods for unconventional digital Jacquard fabric design in colorful mode have been analyzed based on the new technologies and computer applied color theory. The results of this study will enhance further research in the area of digital textile.

GFFD： Generalized free-form deformation with scalar fields

The novel free-form deformation (FFD) technique presented in the paper uses scalar fields definedby skeletons with arbitrary topology. The technique embeds objects into the scalar field by assigning a field value to each point of the objects. When the space of the skeleton is changed, the distribution of the scalar field changes accordingly, which implicitly defines a deformation of the space. The generality of skeletons assures that the technique can freely define deformable regions to produce a broader range of shape deformations.

Analysis of solution findings in the conceptual design of function structures

In the conceptual stage the function design process is realized by the computer aided application. After surveying on the function specification methods and the function modeling, a computer aided function design environment is analyzed. Subsequently based on a module library and principle catalogue, a solution finding process as a part of conceptual design is proposed for a creative design. In addition, a search algorithm to find the solution of adaptable function structure is also discussed. The concepts proposed in this paper can support the subsequent design stages, especially simulation for checking the function structure defects.

A Method for Solving Computer-Aided Product Design Optimization Problem Based on Back Propagation Neural Network

Because of the powerful mapping ability, back propagation neural network (BP-NN) has been employed in computer-aided product design (CAPD) to establish the property prediction model. The backward problem in CAPD is to search for the appropriate structure or composition of the product with desired property, which is an optimization problem. In this paper, a global optimization method of using the a BB algorithm to solve the backward problem is presented. In particular, a convex lower bounding function is constructed for the objective function formulated with BP-NN model, and the calculation of the key parameter a is implemented by recurring to the interval Hessian matrix of the objective function. Two case studies involving the design of dopamine β-hydroxylase (DβH) inhibitors and linear low density polyethylene (LLDPE) nano composites are investigated using the proposed method.

Research and development of a digital design system for hull structures

Methods used for digital ship design were studied and formed the basis of a proposed frame model suitable for ship construction modeling. Based on 3-D modeling software, a digital design system for hull structures was developed. Basic software systems for modeling, modifying, and assembly simulation were developed. The system has good compatibility, and models created by it can be saved in different 3-D file formats, and 2D engineering drawings can be output directly. The model can be modified dynamically, overcoming the necessity of repeated modifications during hull structural design. Through operations such as model construction, intervention inspection, and collision detection, problems can be identified and modified during the hull structural design stage. Technologies for centralized control of the system, database management, and 3-D digital design are integrated into this digital model in the preliminary design stage of shipbuilding.

Knowledge acquisition method for case-knowledge-based product family design

Knowledge acquisition has always been the bottleneck of artificial intelligence. It is the critical point in product family design. Here a knowledge acquisition method was introduced based on scenario model and repository grid and attribute ordering table technology. This method acquired knowledge through providing product design cases to expert, and recording the means and knowledge used by the expert to describe and resolve problems. It used object to express design entity, used scenario to describe the design process, used Event-Condition-Action（ECA） nile to drive design process, and with the help of repository grid and attribute ordering table technology to acquire design knowledge. It＇ s a good way to capture explicit and implicit knowledge. And its validity is proved with respective examples.

Low power implementation of datapath using regularity

Datapath accounts for a considerable part of power consumption in VLSI circuit design. This paper presents a method for physical implementation of datapath to achieve low power consumption. Regularity is a characteristic of datapath and the key of the proposed method, where synthesis is tightly combined with placement to make full use of regularity, so that low power consumption is achieved. In This paper, a new concept of Synthesis In Relative Placement (SIRP) is given to deal with the semi-regularity in some datapath. Experimental results of a sample circuit validated the proposed method.

Research on Design Optimization Strategy in Virtual Product Development

Simulation and optimization are the key points of virtual product development (VPD). Traditional engineering simulation software and optimization methods are inadequate to analyze the optimization problems because of its computational inefficiency. A systematic design optimization strategy by using statistical methods and mathematical optimization technologies is proposed. This method extends the design of experiments (DOE) and the simulation metamodel technologies. Metamodels are built to in place of detailed simulation codes based on effectively DOE, and then be linked to optimization routines for fast analysis, or serve as a bridge for integrating simulation software across different domains. A design optimization of composite material structure is used to demonstrate the newly introduced methodology.

Women's Basic Block Based on the Body Recognition

Body analysis is an important method to clothing construction design. It not only gets the measurement of body, but also analyze the style of body shape. We have discussed the method of woman body fuzzy recognition in another paper and from that we divide woman bodies into thirty-six groups. In each group,bodies have one kind of basic block and there is difference between any two kinds. This paper puts forward thirty-six basic block modes based on various woman bodies.

Research on Garment Pattern Intelligent Design System

This article discusses the disadvantages of current computer aided garment design system first, and then brings forward the frame of intelligent garment design system. Based on the analysis of the structure of the intelligent system, it is pointed out that the intelligent pattern design system is the most important module of the whole system. The use of an expert system to realize the intelligent pattern design system is then proposed and the key technique of the system is discussed at last.

Rational Return——Significance of and Reflection on Freehand Sketching

The overuse of and heavy dependency on a technology will result in the rigidity of thinking, which is true of computer-aided drawing. Due to the similarities in computer graphics, freehand sketching has attracted the public attention again. In this paper, the necessity and importance of freehand sketching were reaffirmed, and suggestions for teaching reform in terms of learning interest, methods, quantity, and achievements were put forward, so as to help students to comprehensively improve their skills and accomplishment in their learning and practice.

USING SYSTEM SIMULATION METHOD AND CAD TECHNIQUE TO SOLVE THE MINING ENGINEERING RELIABILITY IN SURFACE MINES

Subjected to various stochastic factors, surface mining engineering reliability is difficult to solve by using general reliability mathematical method.The concept of reliability measurement is introduced; And the authors have combined system simulation method with CAD technique and developed an interactive color character graphic design system for evaluating and solving the mining engineering reliability in surface mines under the given constraints.

Developing Computer-Based Design Approach to Foster the Architectural Skills of Undergraduate Students in Design Studios

The paper discusses the importance of computer as a supporting approach in architecture. This approach is expected to foster the students＇ design skills in design studios. The approach is an educational tool for tutors that could guide the students and increase their creativity in their design. It considers the concepts and the practice of digital architectural design that influence architectural education. The approach is a catalyst for creativity, experimentation, critical thinking and the sustained growth of creative communities. The core of design studio is the notions, methods and skills of digital architectural design. The instruments used for this research was an investigation that made for the work of the fourth year students designs at the architectural department at University of Jordan, by testing design process and product of students＇ work： first using manual skills, and then using computer-aided programs. The results revealed that the computer-based design approach was able to foster students＇ design skills as well as to develop their creativity in design. Ninety-one percent of 44 students were found improved in design process using computer-based approach that depends on computer programs. This was done in design studio by improving students＇ way of thinking, developing their abilities to direct their own learning and pushing them for new definitions in developing their future work.

The Design of Gear Parameters Visual System based on LISP

Article use Visual LISP development tools and DCL dialog technology, which implements the standard straight teeth, a two- dimensional cylindrical gear paranaetric drawing on AutoCAD platform, with easy to operate and improve design efficiency. We achieved that using the dialog box design input parameters, and gear parts of the design calculations, parameters proofreading and all kinds of gear design drawing different structures by programming. The output is fully automated computer-aided design system. The results show that the design of the system significantly improves the efficiency of the part design.

Parameterization Modeling of a Gas Turbine Coverplate

In order to reduce product development cycle time, aerospace companies tend to develop various correlations integrating geometric and performance parameters. This paper covers the development of a parameterization modeling, to be used in the preliminary design phase, for the turbine cover plate of an aero-engine. The parameterization modeling of the turbine cover plate is achieved by using commercial CAD （computer aided design） software processing in batch mode. Two main approaches are presented the outer face and the skeleton models. These models can then be integrated into an iterative process for designing optimal shapes. Both models are capable of reproducing existing cover plate with reasonable accuracy in relatively shorter time periods. However, the skeleton approach provides probably the best results in terms of flexibility and accuracy, but increases programming complexity and requires greater run times.