Design Synthesis in a Virtual Environment

2001 ◽  
Author(s):  
Douglas Maxwell ◽  
Rob King ◽  
Alley Butler
Keyword(s):  
Virtual Environment ◽  
Computer Aided Design ◽  
Stereoscopic Vision ◽  
Design Environment ◽  
Design Synthesis ◽  
Cad System ◽  
Gestural Interface ◽  
Design Activities ◽  
Immersive Environment ◽  
Aided Design

Abstract Traditional computer-aided design/engineering (CAD/CAE) is performed in a two-dimensional (2D) environment. Through the CAD system demonstration described in this paper, an alternative to the existing 2D technology for design of products is described. This alternative in which design synthesis is accomplished in a stereoscopic or immersive environment is called the Design Synthesis Virtual Environment or DSVE. Stereoscopic vision permits depth perception and provides perception of “real world” 3D existence. This DSVE technology, as defined in this paper, provides a virtual or immersive environment, computer-generated, but seemingly real. The authors argue that significant advantages are possible when an immersive environment such as the DSVE is used for design synthesis. In the Design Synthesis Virtual Environment a gestural interface is used, and it is further argued that designers can perform design activities intuitively by using a more natural gestural interface within the design environment, allowing more rapid, efficient actions to create and/or modify product geometry. As evidence, this paper reports on a demonstration conducted in a Design Synthesis Virtual Environment. Operation of the DSVE is explained, and two example problems are worked. Conclusions are drawn about the effectiveness of the DSVE and the potential for further development.

Vulnerability prediction method for use in aircraft conceptual design

1999 ◽  
Vol 103 (1024) ◽  
pp. 309-315 ◽  
Author(s):  
S. Al-Ahmed ◽  
J. P. Fielding
Keyword(s):  
Computer Aided Design ◽  
Prediction Method ◽  
Preliminary Design ◽  
Solid Modelling ◽  
Design Synthesis ◽  
Cad System ◽  
Vulnerability Assessments ◽  
Critical Components ◽  
Aided Design ◽  
Aircraft Conceptual Design

Abstract A methodology has been developed to integrate the vulnerability discipline into the conceptual/preliminary design process of combat aircraft. An interactive and programmable solid modelling Computer Aided Design (CAD) system is used to generate a CAD solid model of the aircraft’s critical components. The aircraft’s components’ sizes and shapes are pre-defined by a conceptual/preliminary design synthesis computer model. A systematic Child-Parent assembly process is used to model the aircraft vulnerability, by defining the criticality degree of each component in the aircraft assembly. Solid Modelling CAD techniques have been modified to develop techniques to perform the two main standard vulnerability assessments, namely the shotline and vulnerable area methods.

A CAD System for Designers’ Decision Making: An Approach With 2D and 3D Integrated and Hierarchical Assembly Models

1991 ◽  
Author(s):  
S. Minami ◽  
T. Ishida ◽  
S. Yamamoto ◽  
K. Tomita ◽  
M. Odamura
Keyword(s):  
Decision Making ◽  
Computer Aided Design ◽  
Mechanical Design ◽  
Prototype System ◽  
Dimensional Model ◽  
3 Dimensional ◽  
Hierarchical Assembly ◽  
Cad System ◽  
Aided Design ◽  
2D And 3D

Abstract A concept for the initial stage of the mechanical design and its implementation in the computer-aided design (CAD) are presented. The process of decision making in design is: (1) determining an outline of the whole assembly using a 2-dimensional model that is easy to operate; (2) checking the outline using a 3-dimensional model in which it is easy to identify the spatial relationships; (3) determining details of its sub-assemblies or their components using the 2-dimensional model; and (4) checking the details using the 3-dimensional model. The CAD system must provide consistent relationships through all the steps. For that, following functions are implemented in our prototype system: (1) a 2D and 3D integrated model for consistency between 2- and 3-dimensional shapes, (2) a hierarchical assembly model with dimensional constraints for consistency within an assembly and their components, and (3) a check on constraints for consistency between shapes and designers’ intentions. As a result, the system can provide an environment well fitted to the designers’ decision making process.

scholarly journals A preliminary design study for an expander liquid oxygen turbopump

2019 ◽  
Author(s):  
C. Maeding ◽  
L. Souverein ◽  
D. Hummel ◽  
S. Koenigbauer ◽  
A. Wagner ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Performance Estimation ◽  
Liquid Oxygen ◽  
Rocket Propulsion ◽  
Thrust Chamber ◽  
Design Activities ◽  
Speed Selection ◽  
Aided Design ◽  
Structural Aspects ◽  
Turbine Drive

In the recent years, Airbus DS GmbH started a turbopump initiative to buildup fundamental capabilities in analyzing and designing turbomachinery within a German national funded program “TARES.” Turbomachinery is widely used in different rocket propulsion systems and include such parts as pumps and turbines. Turbines are used for generating power required by pumps in order to feed the propellants to the thrust chamber. The paper is dedicated to present an overview about currently ongoing conceptual design activities of turbomachinery covering the main design phases like TPA (TurboPump Assembly) layout tradeoff; rotational speed selection with respect to efficiency and cavitation; flow path design techniques including blade profiling; computer-aided design (CAD) work; and preliminary structural analyses. This paper presents the main outcome applying the established design logic to a liquid oxygen (LOx) turbomachinery. The component is designed based on a dedicated specification for an expander cycle type engine. This includes a LOx pump unit comprising inducer and impeller as well as a subsonic single stage reaction turbine. For the turbine drive, gaseous hydrogen (GH2) heated within the thrust chamber cooling circuit is used. Within this paper, a general overview about the preliminary work results of pump and turbine sizing, profiling, performance estimation as well as structural aspects is given.

A Framework for Designing Component Shapes in a Virtual Reality Environment

1997 ◽  
Author(s):  
Tushar H. Dani ◽  
Rajit Gadh
Keyword(s):  
Virtual Reality ◽  
Virtual Environment ◽  
User Interfaces ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Human Interaction ◽  
Prototype System ◽  
Virtual Design ◽  
Cad System ◽  
Interactive Editing

Abstract Despite advances in Computer-Aided Design (CAD) and the evolution of the graphical user interfaces, rapid creation, editing and visualization of three-dimensional (3D) shapes remains a tedious task. Though the availability of Virtual Reality (VR)-based systems allows enhanced three-dimensional interaction and visualization, the use of VR for ab initio shape design, as opposed to ‘importing’ models from existing CAD systems, is a relatively new area of research. Of interest are computer-human interaction issues and the design and geometric tools for shape modeling in a Virtual Environment (VE). The focus of this paper is on the latter i.e. in defining the geometric tools required for a VR-CAD system and in describing a framework that meets those requirements. This framework, the Virtual Design Software Framework (VDSF) consists of the interaction and design tools, and an underlying geometric engine that provides the representation and algorithms required by these tools. The geometric engine called the Virtual Modeler uses a graph-based representation (Shape-Graph) for modeling the shapes created by the user. The Shape-Graph facilitates interactive editing by localizing the effect of editing operations and in addition provides constraint-based design and editing mechanisms that are useful in a 3D interactive virtual environment. The paper concludes with a description of the prototype system, called the Virtual Design Studio (VDS), that is currently being implemented.1.

Computer-Aided Design Synthesis Using Syntactic Solid Modeling

1994 ◽  
Author(s):  
Vassilios E. Theodoracatos ◽  
Xiaogang Guan
Keyword(s):  
Computer Aided Design ◽  
Solid Modeling ◽  
Large Set ◽  
Complex Structures ◽  
Design Synthesis ◽  
Computer Aided ◽  
Grammar Rules ◽  
Small Set ◽  
Definition Of ◽  
Aided Design

Abstract This paper presents a new Computer-Aided Design (CAD) synthesis model which uses Plex Grammar as structural relationship descriptors and NURBS surface representation for constructing standard and non-standard solid entities. Here, the designer uses a syntactic design methodology for early topological and geometrical definition of the structure of concept alternatives resulting from the design process. This syntactic scheme provides the capability of describing a large set of complex structures by using a small set of simple entities. The recursive nature of the grammar and the hierarchical representation of the structure makes the description of complex structures simple and under the direct control of the designer. An object structure constructive tree is generated and subsequently translated into Plex Grammar production rules in order to form an Interconnection Matrix (ICM) expressing. The resulting Plex structure defined in the ICM expresses the topological information among entities which form the specific types of objects. By modifying the Plex grammar rules, various objects with different geometry and topology can easily be reconstructed. Compared to conventional solid modeling techniques, this approach provides more systematic object generation, easy manipulation and modification, control over congruity and the ability to represent sculptured shapes. Several examples of syntactic solid modeling applied in design synthesis will be presented for further usage in downstream applications.

Iterative Part Design With a Virtual Reality Interface

1996 ◽  
Author(s):  
S. N. Trika ◽  
P. Banerjee ◽  
R. L. Kashyap
Keyword(s):  
Virtual Reality ◽  
Computer Aided Design ◽  
Three Dimensions ◽  
Mechanical Parts ◽  
Cad System ◽  
Current State ◽  
Feature Based ◽  
New Feature ◽  
Feature Based Design ◽  
Aided Design

Abstract A virtual reality (VR) interface to a feature-based computer-aided design (CAD) system promises to provide a simple interface to a designer of mechanical parts, because it allows intuitive specification of design features such as holes, slots, and protrusions in three-dimensions. Given the current state of a part design, the designer is free to navigate around the part and in part cavities to specify the next feature. This method of feature specification also provides directives to the process-planner regarding the order in which the features may be manufactured. In iterative feature-based design, the existing part cavities represent constraints as to where the designer is allowed to navigate and place the new feature. The CAD system must be able to recognize the part cavities and enforce these constraints. Furthermore, the CAD system must be able to update its knowledge of part cavities when the new feature is added. In this paper, (i) we show how the CAD system can enforce the aforementioned constraints by exploiting the knowledge of part cavities and their adjacencies, and (ii) present efficient methods for updates of the set of part cavities when the designer adds a new feature.

Design and Implementation of an Intelligent CAD System

1987 ◽  
Author(s):  
M. J. Jakiela ◽  
P. Y. Papalambros
Keyword(s):  
Computer Aided Design ◽  
Design System ◽  
Knowledge Based Systems ◽  
Production Rules ◽  
Automated Assembly ◽  
Cad System ◽  
Design And Implementation ◽  
Knowledge Based ◽  
System Requirements ◽  
Aided Design

Abstract System requirements and system design for integrating a production rule program and a computer aided design system are presented. An implementation using a commercially available graphics modeling system is described. A “suggestive mode” interface is programmed as an example with application to design for automated assembly. Initial use of the implementation indicates that encoding production rules is more difficult than with conventional text-only knowledge-based systems, but that this system is a more effective way to use artificial intelligence techniques in design.

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