Knowledge-Based Parametric Modeling for Nozzles

This paper describes a new, and unique, system for design and analysis of a family of parts with a specific focus on gas turbine nozzles. The system, built on the tenets of knowledge-based engineering (KBE) within an object-oriented framework, supports the notion of scalable products that can be resized through reparametrization. The KBE system for the parametric design of nozzles has been integrated with a Topology and Geometry Utility System (TAGUS) and geometry-based mesh generators (QUADTREE and EXTREME) to develop a turnkey system. The resulting system is shown to help reduce the design cycle time and to increase engineering productivity by representing design and manufacturing information as part of the complete product definition.

CAFP: Computer-Aided Fixture Planning

Fixture planning is an indispensable part of a manufacturing process planning routine. This paper introduces a rational approach to computer-aided fixture planning (CAFP). A method of fixture classification and selection is introduced for planning of modular fixtures. The location of each fixture component is determined according to the common fixturing principles. We has developed a prototype CAFP system and linked to a commercial CAD system, namely CADAM. Modular fixture elements are automatically selected by the system, and the generated fixture layout can be displayed on-screen after assembly. For verification and optimization of a fixturing scheme, a fixture analysis module is also developed. An iteration method is used to solve the fixturing constraint equations and to determine the adequate clamping forces for holding the workpiece during machining processes.

Frequency Analysis Tools for a First Control Course Using MATLAB

A set of routines is developed using the MATLAB software package to aid students in learning methods of frequency response analysis. Routines are menu driven which would require minimum knowledge of MATLAB commands. A rapid sketch of asymptotic Bode plots is emphasized which is the basis for the lead, lag, and lead-lag compensator design techniques in the first control course taught at Western New England College.

A Mechanical Design Framework Based on Object-Oriented Approach

An object-oriented programming (OOP) technique is investigated in order to develop the framework for mechanical design automation systems. A task-oriented decomposition approach is applied to conceptualize the task-object (or task-performing-object) in which common behavior and communication protocols are encapsulated [1]. Each task in the entire design process, either controlling design strategies or performing design methods, is made into an object. The design method objects are implemented using Artificial Intelligence (AI) paradigms, such as artificial neural networks and expert systems. This report explains how OOP is integrated to develop a mechanical design framework (MDF). A single reduction gear box design process was used to identify some of the general tasks involved in mechanical design process. From this process the guidelines for developing task-objects for future systems are formed. Full details of these guidelines and an implementation example in Smalltalk on a PC are available in [7].

Use of Statistical Modelling Techniques for Simulation

Statistical methods are explored for the use in modelling of discrete manufacturing. The developed methodologies based on Design of Experiments (DOE) and stepwise regression to obtain the product model are described. This model is then embedded within a software system which is used for simulation of design changes, process changes and disturbances. The software is used to predict final test results in respect of up-stream parameter changes. A case study is presented o show the implementation of this method of modelling in Quality Control of manufacture. This case study has successfully been implemented. The system is currently assisting the company in design of similar product. Feasibility of applying Artificial Intelligen (AI) techniques to Model-Based Quality Control (MBQC) is investigated. An outline of the future development of Hybrid MBQC is then presented.

Developing and Integrating CAE Tools in Engineering Technology

Computer Aided Engineering (CAE) Tools are being used extensively by companies in the United States to compete in an increasingly demanding global market place. Product cycle times are being reduced while quality requirements are being increased. The students enrolled in engineering and engineering technology today will be faced with competing in these competitive markets after graduation and must acquire the skills they need for that competition before graduation. In order to help make our students more competitive in that global market place, a CAE Tools course and interdisciplinary projects are being integrated into the manufacturing, plastics and electronics engineering technology programs at Western Washington University. This paper describes the new CAE Tools course at Western and decribes specific examples of interdisciplinary projects during the past academic year.

Dynamics of a Rotating Flexible Multi-Link With Viscoelastic Constraining Layers

Due to an increased flexibility of modern mechanical and structural systems, effective vibration control becomes essential to their high-precision operations. In this paper, dynamics and vibration control of a rotating multi-link are studied. Passive vibration control of the link with distributed viscoelastic layers is studied. Effectiveness of the distributed viscoelastic dampers with various stiffness and damping properties is investigated.

The Finite Element Analysis of Dynamic Interaction of High-Speed Shinkansen, the Rail, and Bridge

A finite element formulation to solve the dynamic behavior of high-speed Shinkansen cars, rail, and bridge is given. A mechanical model to express the interaction between wheel and rail is described, in which the impact of the rail on the flange of wheel is also considered. The bridge is modeled by using various finite elements such as shell, beam, solid, spring, and mass. The equations of motions of bridge and Shinkansen cars are solved under the constitutive and constraint equations to express the interaction between rail and wheel. Numerical method based on a modal transformation to get the dynamic response effectively is discussed. A finite element program for the dynamic response analysis of Shinkansen cars, rail, and bridge at the high-speed running has been developed. Numerical examples are also demonstrated.

MS Windows GUI for Linear Spring Design

Two versions of a Windows-based linear spring design software have been developed. They are presented here to illustrate how graphical user interfaces can enhance the flow of control of a design process. The software also demonstrates that optimized usage of screen space can make an expert system based design software more intuitive. The two software presented here illustrate that well conceived GUI’s can improve the productivity of a design engineer.

Towards a Consistency Management in a Feature-Based Design

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.