Consistency Management in Feature-Based Parametric Design

Author(s):  
Ana Sofia Vieira

Abstract One of the main problems to be solved in design-by-features is to preserve the semantic correctness of feature-based models. Currently, feature-based parametric design (FbPD) is being used as one of the most powerful approaches for solving this problem. In this paper, a fundamental principle of this approach is introduced. Three aspects stated, are: FbPD deals with functional design primitives, it solves the automatic generation of model variations, and it offers the basis for the development of a mechanism to check the semantic correctness of feature-based models. Several concepts for the definition of semantic constraints are presented. They instigate the classification of semantic constraints in four different categories, based on the constraint evaluation-time, purpose, behaviour, and representation. Sinfonia, a system for feature-based parametric design, is presented as a testbed environment for design-by-features applications. One of its modules, the Consistency Handler, uses the constraint concepts introduced in order to preserve the semantic consistency of the models. Several examples illustrate the different types of constraints. In addition, an algorithm applied for the process of a consistent feature modification is presented.

2010 ◽  
Vol 42 ◽  
pp. 396-399
Author(s):  
Xing Xin Xu ◽  
Xiao Hui Zhang ◽  
You Yi Zheng

From the definition of logarithmic spiral and its particular characteristics, logarithmic spiral is discussed and adopted as the tooth back curve of the relieving shaped milling cutter under the new manufacturing conditions. Thus, the relief angle of each point on the cutting edge keeps instant after regrinding the cutter and thereby makes for preserving the machinability stability. Besides, cutter structure parameters determine coefficient values in the equation of logarithmic spiral tooth back curve. Based on the objected-oriented thought, a CAD system for the relieving shaped milling cutter with logarithmic spiral tooth back is developed in virtue of the language of VBA embedded in AutoCAD, which achieves the automatic generation of logarithmic spiral, realizes the cutter parametric design, shortens the whole cycle and improves the design quality.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Liqun Dong ◽  
Junwei Zhang ◽  
Liang Qin ◽  
Ping Xue ◽  
Yun Ma ◽  
...  

Abstract Owing to the existence of the cone angle, the size of a conical counter-rotating twin screw continuously changes along the axis, so it is not easy to model using SolidWorks. In this study, the parametric design of the modeling process is completed based on the Visual Basic language and a program-driven method. Finally, the SolidWorks program plug-in and user interface are developed to complete the automatic generation of the three-dimensional model of a conical counter-rotating twin screw.


Author(s):  
David W. Rosen

Abstract Features are meaningful abstractions of geometry that engineers use to reason about components, products, and processes. For design activity, features are design primitives, serve as the basis for product representations, and can incorporate information relevant to life-cycle activities such as manufacturing. Research on feature-based design has matured to the point that results are being incorporated into commercial CAD systems. The intent here is to classify feature-based design literature to provide a solid historical basis for present research and to identify promising research directions that will affect computer-based design tools within the next few years. Applications of feature-based design and technologies of feature representations are reviewed. Open research issues are identified and put in the context of past and current work. Four hypotheses are proposed as challenges for future research: two on the existence of fundamental sub-feature elements and relationships for features, one that presents a new definition of design features, and one that argues for the successful development of concurrent engineering languages. Evidence for these hypotheses is provided from recent research results and from speculation about the future of feature-based design.


2014 ◽  
Vol 511-512 ◽  
pp. 573-577
Author(s):  
Feng Jun Wang

In this paper the characteristics of the piston features for classification and feature library; at the same time the feature size and the feature existence parametric methods are discussed in detail. In a detailed analysis of the engine piston load based on, forward piston mechanical,thermal boundary conditions, forward piston mechanical, thermal boundary conditions, the results show that the original piston has a larger reserve strength, this research provided probility for the further optimization.


2010 ◽  
Vol 29 (4) ◽  
pp. 171 ◽  
Author(s):  
Alessio Malizia ◽  
Paolo Bottoni ◽  
S. Levialdi

The design and development of a digital library involves different stakeholders, such as: information architects, librarians, and domain experts, who need to agree on a common language to describe, discuss, and negotiate the services the library has to offer. To this end, high-level, language-neutral models have to be devised. Metamodeling techniques favor the definition of domainspecific visual languages through which stakeholders can share their views and directly manipulate representations of the domain entities. This paper describes CRADLE (Cooperative-Relational Approach to Digital Library Environments), a metamodel-based framework and visual language for the definition of notions and services related to the development of digital libraries. A collection of tools allows the automatic generation of several services, defined with the CRADLE visual language, and of the graphical user interfaces providing access to them for the final user. The effectiveness of the approach is illustrated by presenting digital libraries generated with CRADLE, while the CRADLE environment has been evaluated by using the cognitive dimensions framework.


2008 ◽  
Vol 52 (01) ◽  
pp. 1-15
Author(s):  
F. L. Pérez ◽  
J. A. Clemente ◽  
J. A. Suárez ◽  
J. M. González

This paper deals with the use of a simple parametric design method applied to simple hull lines, such as sailing ship hulls and round bilge hulls. The described method allows the generation of hull lines that meet hydrodynamic coefficients imposed by the designer, obtaining more flexibility than with normal affine transformations of a parent hull. First, a wire model of the ship stations is made with the use of explicit curves. The method is completed with an automatic surface modeling of the previ¬ously generated offsets. The construction of spline curves and their application in the definition of ship lines are reviewed. Approximation of spline curves fitting the data on the stations is made, with special emphasis on the choice of parametrization, which is relevant to increasing the accuracy of the splines. B-spline surface modeling of the hull and the fairing process adapted to maintain certain ship characteristics are described. Some examples of the generation, lofting, and fairing process are pre¬sented.


Author(s):  
Nanxin Wang ◽  
Tulga M. Ozsoy

Abstract This paper presents an algorithm for generating tolerance chains from the mating relations between components of assemblies. The algorithm is developed upon a feature-based assembly modeling strategy that represents each component in close relation to its mating features, dimensions and tolerances. The mating relations within an assembly are described by a mating graph. Tolerance chains together with their dimensions and tolerances are generated automatically by searching through a mating graph for matching mating features. A prototype program package based on the presented algorithm has been developed, and several examples of various complexity have been tested with success.


Author(s):  
Jivka Ovtcharova ◽  
Uwe Jasnoch

Abstract It is a common goal in the development of feature-based design systems to support users with extended facilities, such as comprehensive semantically correct feature-based models, conformability of tools to user requirements and to different applications, and communication via standardized interfaces. However, the current state of the art in feature-based design does not meet the most of these requirements, particularly the integration of design, reliability and maintainability of constraints. This paper presents recent research on design by features using the constraint satisfaction approach. We determine the basic requirements for defining and administering constraints in feature-based models and propose an architecture for consistency management in feature-based design systems. The two main modules of interest are Feature Frame and Consistency Manager. The Feature Frame intends to enclose different feature data into one information set, called Feature Resources and to create and manipulate such resources using Feature Mechanisms. The Consistency Manager provides functionality for definition, evaluation and satisfaction of constraints in feature-based models. Furthermore, in this paper the relation between feature-based design, consistency management and object-oriented paradigm is clarified. In contrast to previous publications where features and constraints are associated with objects in a programming language sense, our starting point is the ontological view to the object concept. We advocate that features and constraints are not objects themselves, but attributes and laws assigned by us to objects to describe properties of them. Thus, feature-based design can be characterized as the art of defining and manipulating properties of design objects.


Author(s):  
Li-Minn Ang ◽  
King Hann Lim ◽  
Kah Phooi Seng ◽  
Siew Wen Chin

This chapter presents a new face recognition system comprising of feature extraction and the Lyapunov theory-based neural network. It first gives the definition of face recognition which can be broadly divided into (i) feature-based approaches, and (ii) holistic approaches. A general review of both approaches will be given in the chapter. Face features extraction techniques including Principal Component Analysis (PCA) and Fisher’s Linear Discriminant (FLD) are discussed. Multilayered neural network (MLNN) and Radial Basis Function neural network (RBF NN) will be reviewed. Two Lyapunov theory-based neural classifiers: (i) Lyapunov theory-based RBF NN, and (ii) Lyapunov theory-based MLNN classifiers are designed based on the Lyapunov stability theory. The design details will be discussed in the chapter. Experiments are performed on two benchmark databases, ORL and Yale. Comparisons with some of the existing conventional techniques are given. Simulation results have shown good performance for face recognition using the Lyapunov theory-based neural network systems.


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