Modified Method of State Variables

2019 ◽  
pp. 19-28
Author(s):  
V. A. Trudonoshin ◽  
V. G. Fedoruk
Keyword(s):  
Mathematical Model ◽  
Computer Aided Design ◽  
Classical Method ◽  
Model Development ◽  
State Variables ◽  
Cad System ◽  
Modified Method ◽  
Graph Tree ◽  
Formation Method ◽  
Aided Design

Formal mathematical model development of an object with lumped parameters is an integral part of CAE systems. The computer-aided design (CAD) system functionality largely depends on the formation method used. The article proposes to modify a method of state variables, which is a pioneer in formal mathematical models development of technical objects whose behaviour is described by a system of ordinary differential equations.The classical method of state variables uses a graph-based representation of the object structure and allows development of its mathematical model in the normal Cauchy form without incorrect locations. The incorrect locations mean situations when capacitance-type branches fall in the graph chords or inductance-type branches fall in the graph tree branches. If there are incorrect locations in the object’s scheme then, to have a model of correct development, additional elements are included to eliminate them. Such an approach is possible if the object description is performed at the level of the basic two-poles, but it is assumed that in all modern CAD systems there is a pre-processor in which it is possible (and as a rule) to use multi-pole components. In this case, it is challenging for an unsophisticated user to make scheme correction.The modified method of state variables proposed in the article is free from this drawback and allows us to obtain a mathematical model in the normal Cauchy form and with incorrect locations available. This will allow us to use both explicit and implicit integration methods, conduct modal analysis, and simply have a model version in the FMI standard.

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 RATIONAL CHOICE OF MACHINING TOOLS USING PREDICTION PROCEDURES

2018 ◽  
Vol 4 ◽  
pp. 14-20 ◽  
Author(s):  
Oleg Krol ◽  
Volodymyr Sokolov
Keyword(s):  
Computer Aided Design ◽  
Metal Cutting ◽  
Selection Process ◽  
Information Source ◽  
Prediction Method ◽  
3D Models ◽  
General Definition ◽  
Static Data ◽  
Graph Tree ◽  
Aided Design

Introducing the methods and procedures for predictive analysis into the design process contours of a variety of machining tools (MT) of metal cutting machines is the main aim of this article. A sequence of realization of prediction object (PO) choice as an initial stage of search of perspective designs is offered. Effective in this regard is the "Tree of objectives" apparatus, on the basis of which many ways of improving MT are formed, selecting progressive (reducing the dimension of the problem) at each level of the hierarchy of the constructed graph-tree. The procedure for selecting the prediction method (PM) as a means of generating the forecast data is developed. The task of choosing a method is structured in detail and uses "Information supply"as the main criterion. To this end, assessment scales of choice criteria have been formed, on the basis of which it is possible to evaluate their effectiveness for the PM selection process. The rules forPOcoding are introduced by a three-element information code, including information source classes – static data, expert estimates and patent data. The process of forecasting the MT components by the method of engineering forecasting on the basis of a representative patent fund is realized. The General Definition Table has been built (GDT "Machining tools") and estimates of the prospects of design solutions have been obtained. A fragment of the database of 3D models of promising MT designs in the integrated computer-aided design KOMPAS-3D is proposed.

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.

An Automated Process Sequence Design and Finite Element Simulation of Axisymmetric Deep Drawn Components

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Ali Fazli ◽  
Behrooz Arezoo ◽  
Mohammad H. Hasanniya
Keyword(s):  
Finite Element ◽  
Computer Aided Design ◽  
Die Design ◽  
Automatic Process ◽  
Blank Holder ◽  
Cad System ◽  
Process Sequence ◽  
Element Simulation ◽  
Process Sequence Design ◽  
Aided Design

A computer-aided design (CAD) system is developed for automatic process design and finite element (FE) modeling of axisymmetric deep drawn components. Using the theoretical and experimental rules, the system initially designs the process sequence of the component. The obtained process sequence is automatically modeled in abaqus software and the system tests whether failure occurs. The failure is supposed to happen when the fracture is predicted in FE simulation. If failure is predicted, the system changes the appropriate process parameters and carries out the simulation process again until all drawing stages are successful. The system returns the requested parameters for die design such as part geometries in middle stages, drawing forces, blank-holder forces, die, and punch profiles radii. The system is successfully tested for some components found in industry and handbooks.

A Web-based Product Structure Manager to Support Collaborative Assembly Modeling1

2004 ◽  
Vol 4 (1) ◽  
pp. 67-78 ◽  
Author(s):  
Li Chen, ◽  
Tingjin Wang, and ◽  
Zhijie Song
Keyword(s):  
Computer Aided Design ◽  
Product Structure ◽  
Web Based ◽  
Assembly Modeling ◽  
Product Structure Management ◽  
Cad System ◽  
Collaborative Assembly ◽  
3D Assembly ◽  
Function Module ◽  
Aided Design

Collaborative CAD systems enabling collaboration in computer-aided design processes among distributed designers are gaining more and more attention. Yet, such systems, especially in support of collaborative assembly modeling, are hardly achievable. In an effort to bridge this gap, we are dedicated to developing a collaborative CAD system with aim at 3D assembly modeling. As part of this effort, this paper addresses one function module of the system, a Web-based Product Structure Manager, which enables the Collaborative Product Structure Management (CPSM) in collaborative assembly modeling. In particular, CPSM facilitates product data sharing among distributed designers and supports collaboration in product structure creation and modification. A bench clamp assembly is used as an example to illustrate the Product Structure Manager for supporting collaborative assembly modeling.

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