An application of the energy barrier to prismatic 2 1/2-dimensional parts of uniform cross-section with non-orthogonal contiguous faces

1997 ◽  
Vol 211 (8) ◽  
pp. 627-633
Author(s):  
S G Lee ◽  
S W Lye ◽  
B K A Ngoi ◽  
L E N Lim
Keyword(s):  
Cross Section ◽  
Computer Aided Design ◽  
Energy Barrier ◽  
Triangular Prism ◽  
Barrier Method ◽  
Cad System ◽  
Design Computation ◽  
Uniform Cross Section ◽  
Aided Design

The energy barrier method, first proposed by Boothroyd and associates, can be used to determine the probabilities of the natural resting aspects of objects to be conveyed on and oriented by vibratory devices. However, for parts of uniform cross-section other than square or rectangular ones, the application of the method can be intractable. In such cases, Boothroyd and associates recommended circumscribing the part by a cylinder and using the energy barrier for the cylinder to approximate the probabilities of the natural resting aspects of the part. This approximation is understandably inexact although computationally expedient. This paper outlines the CAD (computer aided design) computation of the probabilities from the energy barriers for two objects: one, a triangular prism with equilateral sides (representing objects with adjacent faces that are not mutually perpendicular) and the second, an L-shaped prism with a virtual resting aspect. The significance of the centroid plane of the part in the determination of the probabilities is discussed. The CAD computations were carried out using the Graphical Interface Programming (GRIP) Language of McDonnell Douglas' UniGraphics II™ CAD system running on a DEC 9000 workstation.

Analysing the Natural Resting Aspects of a Component for Automated Assembly

1995 ◽  
Vol 209 (2) ◽  
pp. 125-131 ◽  
Author(s):  
B K A Ngoi ◽  
L E N Lim ◽  
S S G Lee ◽  
S W Lye
Keyword(s):  
Cross Sections ◽  
Computer Aided Design ◽  
Energy Barrier ◽  
Three Dimensional ◽  
Rectangular Prism ◽  
Automatic Assembly ◽  
Automated Assembly ◽  
Barrier Method ◽  
Aided Design ◽  
Natural Resting Aspect

This paper proposes the construction of an energy envelope that can be used to advantage with the energy barrier method to analyse the natural resting aspect of engineering parts destined for automatic assembly. Unlike the energy barrier method, the energy envelope does not require any visualization of the projection of the energy barrier on the aspect of interest. The energy envelope is the three-dimensional topology of the changes in height of the centroid, as the part attempts changes of aspect. The paper describes how it may be computed in a CAD (computer aided design) solid modeller. The results of applying the energy envelope to prisms of square and cylindrical cross-sections are the same as those predicted by the energy barrier method. When extended to the analysis of a rectangular prism, the results were consistent with Boothroyd's dynamic solution and Boothroyd's experimental data. This conclusion is encouraging as there is no irrefutable evidence that the energy barrier method may be applied to the analysis of the rectangular prism.

Designing of Outriggers for the Needs of the Vehicles Stability Testing

2018 ◽  
Vol 875 ◽  
pp. 71-76
Author(s):  
Victor Kryaskov ◽  
Andrey Vashurin ◽  
Anton Tumasov ◽  
Alexey Vasiliev
Keyword(s):  
Coefficient Of Friction ◽  
Computer Aided Design ◽  
Strength Analysis ◽  
Direct Impact ◽  
Stability Testing ◽  
Supporting Surface ◽  
Stability Tests ◽  
Computer Aided ◽  
Aided Design

This paper is dedicated to the issues of designing of outriggers for avoidance of vehicle tilting during its stability tests. An analysis of existing types of outriggers was done by authors as well as legislative requirements on them. The reliable and well-timed operation of outriggers largely depends on the height of their positioning on a vehicle. In order to determine this important parameter a special methodic of determining the tipping angle of the vehicle with the use of computer-aided design (CAD) was composed by authors. The article also contains some main principles of strength analysis of the structure a very important part of which became the necessity of determination of coefficient of friction between the outrigger sliders and the supporting surface. This coefficient has a direct impact on the value of transverse forces appearing at the ends of outrigger beams.

Determination of the Workspace of a Three-Degrees-of-Freedom Parallel Manipulator Using a Three-Dimensional Computer-Aided-Design Software Package and the Concept of Virtual Chains1

2015 ◽  
Vol 8 (2) ◽  
Author(s):  
Andrew Johnson ◽  
Xianwen Kong ◽  
James Ritchie
Keyword(s):  
Computer Aided Design ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Graphical Representation ◽  
Three Dimensional ◽  
Parallel Manipulators ◽  
Workspace Analysis ◽  
Computer Aided ◽  
Aided Design

The determination of workspace is an essential step in the development of parallel manipulators. By extending the virtual-chain (VC) approach to the type synthesis of parallel manipulators, this technical brief proposes a VC approach to the workspace analysis of parallel manipulators. This method is first outlined before being illustrated by the production of a three-dimensional (3D) computer-aided-design (CAD) model of a 3-RPS parallel manipulator and evaluating it for the workspace of the manipulator. Here, R, P and S denote revolute, prismatic and spherical joints respectively. The VC represents the motion capability of moving platform of a manipulator and is shown to be very useful in the production of a graphical representation of the workspace. Using this approach, the link interferences and certain transmission indices can be easily taken into consideration in determining the workspace of a parallel manipulator.

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 COMPLEX USAGE OF 4D INFORMATION MODELLING CONCEPT FOR BUILDING DESIGN, ESTIMATION, SHEDULING AND DETERMINATION OF EFFECTIVE VARIANT

2006 ◽  
Vol 12 (2) ◽  
pp. 91-98 ◽  
Author(s):  
Vladimir Popov ◽  
Saulius Mikalauskas ◽  
Darius Migilinskas ◽  
Povilas Vainiūnas
Keyword(s):  
Computer Aided Design ◽  
Information Technologies ◽  
Investment Project ◽  
Building Design ◽  
Product Lifecycle Management ◽  
Information Modeling ◽  
Information Modelling ◽  
Computer Aided ◽  
Aided Design

With the growth of information technologies in the field of construction industry, the concept of CAD (Computer Aided Design), which denotes just design operations using a computer acquires a new meaning and changes the contents lightening design process based on product modelling and further numerical simulation construction process and facility managing. New definitions as Building Information Modelling (BIM) and Product Lifecycle Management (PLM) are more and more usable as the definition of a new way approaching the design and documentation managing of building projects. The presented computer aided design technology based on the concept of graphical ‐ information modeling of a building, is combined with resource demand calculations, comparison of alternatives and determination of duration of all the stages of investment project life. The software based on this combined 4D PLM model is to be created as a means to manage effectively the investment project, starting from planning, designing, economical calculations, construction and afterwards to manage the finished building and to utilize it.

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.

Simultaneous Computer-Aided Design of Rotational Plastic Parts

1993 ◽  
Author(s):  
Colin Chong ◽  
Kiyoshi Sogabe ◽  
Kosuke Ishii
Keyword(s):  
Injection Molding ◽  
Dynamic Characteristics ◽  
Computer Aided Design ◽  
Critical Speed ◽  
Dynamic Balance ◽  
Cad System ◽  
Compatibility Analysis ◽  
Computer Aided ◽  
Plastic Parts ◽  
Aided Design

Abstract This paper addresses the problem of balancing rotational plastic parts during the early stages of design. The study develops an interactive methodology that uses a solid modeling CAD system and considers injection molding concerns simultaneously with static and dynamic balance. The Transfer Matrix Method evaluates the dynamic characteristics by predicting the approximate critical speed of the part. Design Compatibility Analysis (DCA) checks for injection molding guidelines. Using these evaluation modules interactively, designers can develop a functional and manufacturable part quickly.

Geometric Modelling and Computer-Aided Design

2009 ◽  
pp. 1-31
Author(s):  
Xun Xu
Keyword(s):  
Computer Aided Design ◽  
Data Exchange ◽  
Geometric Model ◽  
Point Of View ◽  
Geometric Modelling ◽  
Cad Systems ◽  
Cad System ◽  
Wire Frame ◽  
Computer Aided ◽  
Aided Design

One of the key activities in any product design process is to develop a geometric model of the product from the conceptual ideas, which can then be augmented with further engineering information pertaining to the application area. For example, the geometric model of a design may be developed to include material and manufacturing information that can later be used in computer-aided process planning and manufacturing (CAPP/CAM) activities. A geometric model is also a must for any engineering analysis, such as finite elopement analysis (FEA). In mathematic terms, geometric modelling is concerned with defining geometric objects using computational geometry, which is often, represented through computer software or rather a geometric modelling kernel. Geometry may be defined with the help of a wire-frame model, surface model, or solid model. Geometric modelling has now become an integral part of any computer-aided design (CAD) system. In this chapter, various geometric modelling approaches, such as wire-frame, surface, and solid modelling will be discussed. Basic computational geometric methods for defining simple entities such as curves, surfaces, and solids are given. Concepts of parametric, variational, history-based, and history-free CAD systems are explained. These topics are discussed in this opening chapter because (a) CAD was the very first computer-aided technologies developed and (b) its related techniques and methods have been pervasive in the other related subjects like computer-aided manufacturing. This chapter only discusses CAD systems from the application point of view; CAD data formats and data exchange issues are covered in the second chapter.

scholarly journals Feature-based translation of CAD models with macro-parametric approach: issues of feature mapping, persistent naming, and constraint translation

2020 ◽  
Vol 7 (5) ◽  
pp. 603-614 ◽  
Author(s):  
Mutahar Safdar ◽  
Tahir Abbas Jauhar ◽  
Youngki Kim ◽  
Hanra Lee ◽  
Chiho Noh ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Parametric Approach ◽  
Model Data ◽  
Feature Mapping ◽  
Product Model ◽  
Cad Systems ◽  
Cad System ◽  
Cad Models ◽  
Feature Based ◽  
Aided Design

Abstract Feature-based translation of computer-aided design (CAD) models allows designers to preserve the modeling history as a series of modeling operations. Modeling operations or features contain information that is required to modify CAD models to create different variants. Conventional formats, including the standard for the exchange of product model data or the initial graphics exchange specification, cannot preserve design intent and only geometric models can be exchanged. As a result, it is not possible to modify these models after their exchange. Macro-parametric approach (MPA) is a method for exchanging feature-based CAD models among heterogeneous CAD systems. TransCAD, a CAD system for inter-CAD translation, is based on this approach. Translators based on MPA were implemented and tested for exchange between two commercial CAD systems. The issues found during the test rallies are reported and analyzed in this work. MPA can be further extended to remaining features and constraints for exchange between commercial CAD systems.

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