Defining and Recognizing Cavity and Protrusion by Volumes

1993 ◽  
Author(s):  
Hiroshi Sakurai ◽  
Chia-Wei Chin
Keyword(s):  
Feature Recognition ◽  
Graph Matching ◽  
Solid Model ◽  
Solid Object ◽  
Spatial Decomposition ◽  
Solid Models ◽  
Design And Manufacturing ◽  
Convexity And Concavity ◽  
Better Than

Abstract In design and manufacturing, cavity features, such as holes and pockets, and protrusion features, such as bosses and ribs are commonly used. In this work, cavity and protrusion in a solid object were defined with the volumes enclosed by the faces of the object and their extensions. These definitions of cavity and protrusion match our intuitive notions of cavity and protrusion better than the commonly used definitions that consider the convexity and concavity of edges. Together with an algorithm called “spatial decomposition and composition”, the definitions provide a method to find cavities and protrusions in solid models. By applying graph matching commonly used in feature recognition to the volumes of cavity and protrusion, all the features in a solid model can be recognized whether they intersect or not.

Local Symmetry Based Hint Extraction of B-Rep Model for Machining Feature Recognition

2018 ◽  
Author(s):  
Zhi Li ◽  
Jie Lin ◽  
Danchen Zhou ◽  
Bo Zhang ◽  
Hai Li
Keyword(s):  
Symmetry Property ◽  
Feature Detection ◽  
Feature Recognition ◽  
Feature Matching ◽  
Graph Matching ◽  
Local Property ◽  
Local Symmetry ◽  
Streaming Applications ◽  
Machining Feature ◽  
Solid Models

Machining feature recognition is a key technology in design for manufacturing, inter-operation of neutral format solid models, and reuse of design models in down-streaming applications. Although many approaches have been proposed, the detection and processing of intersection features are still challenging. In this paper, we studied the local property of B-rep model and usage in intersection feature detection. To support hint based reasoning and processing, we proposed a symmetry property definition with relation to edges of solid models. This symmetry property is based on conventional edge convexity, which is an extension of the feature hint theory. The Transformation of global or partial graph matching to local property matching would reduce the complexity in feature matching stages. We implemented a prototype module to evaluate the feasibility of the proposed approach.

scholarly journals Design Parameterization for Concurrent Design and Manufacturing of Mechanical Systems

2001 ◽  
Author(s):  
Kuang-Hua Chang ◽  
Javier Silva
Keyword(s):  
Product Design ◽  
Computer Aided Design ◽  
Product Development Process ◽  
Solid Model ◽  
Concurrent Design ◽  
Product Model ◽  
Design Changes ◽  
Solid Models ◽  
Design And Manufacturing ◽  
Product Assembly

Abstract Design changes are frequently encountered in the product development process. The complexity of the design changes is multiplied when the product design involves multiple engineering disciplines. Very often, a simple change in one part may propagate to its neighboring parts, therefore, affects the entire product assembly. Both parts and assembly must be regenerated for a physically valid product model, at the same time, the regenerated product model must meet designer’s expectations. When a product is being developed in a Concurrent Design and Manufacturing (CDM) environment, the design changes are usually implemented first by altering geometry of the product represented in computer-aided design (CAD) solid models. If the product solid model is not parameterized properly, the changes in geometry often lead to invalid parts or assembly. At the part level, the changes may yield a solid model with invalid geometric features if it is not properly parameterized. In this case, the entire product assembly is in vain. Even when individual parts of the product are regenerated correctly, parts may still penetrate to their neighboring parts or leave excessive gaps among them, if the solid model is not properly parameterized at the assembly level. In this paper, solid modeling and assembly techniques implemented in two major CAD tools, Pro/ENGINEER and SolidWorks, will be discussed. A set of guidelines will be proposed for the designers to parameterize the solid models in order to capture the design intents more effectively in the product virtual mockup. These guidelines at both part and assembly levels will support designers to successfully conduct product design in the CDM environment. A number of examples, including a slider-crank mechanism and its crankshaft, a single-piston airplane engine and its components, as well as a number of simpler parts are presented to illustrate and demonstrate the parameterization method and guidelines proposed for both Pro/ENGINEER and SolidWorks.

MMCs and PPCs As Constructs of Curvature Regions for Form Feature Determination

1997 ◽  
Author(s):  
Ratnakar Sonthi ◽  
Rajit Gadh
Keyword(s):  
Feature Recognition ◽  
Geometric Model ◽  
Boundary Representation ◽  
Solid Model ◽  
Cad Model ◽  
Solid Models ◽  
Feature Information ◽  
Primitive Shape ◽  
Region Representation ◽  
Form Feature

Abstract Shape feature information about a part is required to analyze the part for downstream issues such as manufacturability and assemblability. One method of obtaining the feature information is feature recognition from the geometric model. This paper presents an approach called Curvature Region (CR) approach for feature determination in solid models. The CR-approach categorizes features into two primitive shape classes: protrusions and depressions. In the first step, these primitive shape classes are recognized from the solid model. In the next step, the primitive shape classes are analyzed using rules to obtain features. Primitive features are found by first converting the boundary representation (B-Rep) of the CAD model to a higher level of representation called Curvature Region Representation (CR-Rep). Curvature Regions are then grouped together to form Minus-Minus Centers (MMCs) and Plus-Plus Centers (PPCs). Primitive shapes are then defined in terms of these centers.

Interactive Feature Recognition Using Multi-Processor Methods

1995 ◽  
Author(s):  
William C. Regli ◽  
Satyandra K. Gupta ◽  
Dana S. Nau
Keyword(s):  
Feature Recognition ◽  
Low Cost ◽  
Computation Time ◽  
Critical Factor ◽  
Solid Models ◽  
Large Numbers ◽  
Design And Manufacturing ◽  
Computational Resources ◽  
Interactive Feature ◽  
Design Analyses

Abstract The availability of low-cost computational power is enabling development of increasingly sophisticated CAD software. Automation of design and manufacturing activities poses many difficult computational problems. Design is an interactive process and speed is a critical factor in systems that enable designers to explore and experiment with alternative ideas. As more downstream manufacturing activities are considered during the design phase, computational costs become problematic. Achieving interactivity requires a sophisticated allocation of computational resources in order to perform realistic design analyses and generate feedback in real time. This paper presents our initial efforts to use distributed algorithms to recognize machining features from solid models of parts with large numbers of features and many geometric and topological entities. Our goal is to outline how significant improvements in computation time can be obtained using existing hardware and software tools. An implementation of our approach is discussed.

A new approach based on graph matching and evolutionary approach for sport scheduling problem

2020 ◽  
pp. 1-16
Author(s):  
Meriem Khelifa ◽  
Dalila Boughaci ◽  
Esma Aïmeur
Keyword(s):  
Graph Matching ◽  
State Of The Art ◽  
Travel Cost ◽  
Round Robin ◽  
New Approach ◽  
Traveling Tournament Problem ◽  
Significant Interest ◽  
National League ◽  
Better Than

The Traveling Tournament Problem (TTP) is concerned with finding a double round-robin tournament schedule that minimizes the total distances traveled by the teams. It has attracted significant interest recently since a favorable TTP schedule can result in significant savings for the league. This paper proposes an original evolutionary algorithm for TTP. We first propose a quick and effective constructive algorithm to construct a Double Round Robin Tournament (DRRT) schedule with low travel cost. We then describe an enhanced genetic algorithm with a new crossover operator to improve the travel cost of the generated schedules. A new heuristic for ordering efficiently the scheduled rounds is also proposed. The latter leads to significant enhancement in the quality of the schedules. The overall method is evaluated on publicly available standard benchmarks and compared with other techniques for TTP and UTTP (Unconstrained Traveling Tournament Problem). The computational experiment shows that the proposed approach could build very good solutions comparable to other state-of-the-art approaches or better than the current best solutions on UTTP. Further, our method provides new valuable solutions to some unsolved UTTP instances and outperforms prior methods for all US National League (NL) instances.

The Geometrical Feature Recognition Method of Part Drawing

2011 ◽  
Vol 415-417 ◽  
pp. 523-526
Author(s):  
Yan Dong ◽  
Mei Li
Keyword(s):  
Feature Recognition ◽  
Graph Matching ◽  
Geometric Feature ◽  
Recognition Method ◽  
Recognition Mechanism ◽  
Chemical Database ◽  
Geometry Feature ◽  
Constraint Structure ◽  
Geometric Elements ◽  
Fine Tune

This paper put forward a geometry feature recognition method of part drawing based on graph matching. Describe the constraints structure of geometric feature in geometric elements and those constraint relationships. Match sub-graph in contour closure graphics and those combination. Using linear symbol notation of chemical compounds in chemical database for reference, encode to constraint structure of geometry graphics, establish recognition mechanism of geometric characteristics by structure codes. Taking the fine-tune screw and fork parts for example, this method has been proved to be effective.

scholarly journals A Rule-Based System to Promote Design for Manufacturing and Assembly in the Development of Welded Structure: Method and Tool Proposition

2021 ◽  
Vol 11 (5) ◽  
pp. 2326
Author(s):  
Claudio Favi ◽  
Roberto Garziera ◽  
Federico Campi
Keyword(s):  
Feature Recognition ◽  
Explicit Knowledge ◽  
Parametric Modeling ◽  
Rule Based ◽  
Rule Based System ◽  
Assembly Method ◽  
Welded Structure ◽  
Design And Manufacturing ◽  
Time Required ◽  
Welding Processes

Welding is a consolidated technology used to manufacture/assemble large products and structures. Currently, welding design issues are tackled downstream of the 3D modeling, lacking concurrent development of design and manufacturing engineering activities. This study aims to define a method to formalize welding knowledge that can be reused as a base for the development of an engineering design platform, applying design for assembly method to assure product manufacturability and welding operations (design for welding (DFW)). The method of ontology (rule-based system) is used to translate tacit knowledge into explicit knowledge, while geometrical feature recognition with parametric modeling is adopted to couple geometrical information with the identification of welding issues. Results show how, within the design phase, manufacturing issues related to the welding operations can be identified and fixed. Two metal structures (a jack adapter of a heavy-duty prop and a lateral frame of a bracket structure) fabricated with arc welding processes were used as case studies and the following benefits were highlighted: (i) anticipation of welding issues related to the product geometry and (ii) reduction of effort and time required for the design review. In conclusion, this research moves forward toward the direction of concurrent engineering, closing the gap between design and manufacturing.

Midsurface Abstraction From 3D Solid Models for Engineering Analysis

1996 ◽  
Author(s):  
Mohsen Rezayat
Keyword(s):  
Feature Recognition ◽  
Analysis Model ◽  
Thin Sections ◽  
New Approach ◽  
Solid Models ◽  
Product And Process ◽  
Plastic Parts ◽  
3D Solid ◽  
User Friendly ◽  
Analysis Models

Abstract An integral part of implementing parallel product and process designs is simulation through numerical analysis. This simulation-driven design requires discretization of the 3D part in an appropriate manner. If the part is thin or has thin sections (e.g., plastic parts), then an analysis model with reduced dimensionality may be more accurate and economical than a standard 3D model. In addition, substantial simplification of some details in the design geometry may be beneficial and desirable in the analysis model. Unfortunately, the majority of CAD systems do not provide the means for abstraction of appropriate analysis models. In this paper we present a new approach, based on midsurface abstraction, which holds significant promise in simplifying simulation-driven design. The method is user-friendly because very little interaction is required to guide the software in its automatic creation of the desired analysis model. It is also robust because it handles typical parts with complex and interacting features. Application of the method for feature recognition and abstraction is also briefly discussed.

Heuristics Based Feature Recognition: A Graph Approach

1994 ◽  
Author(s):  
Shyam V. Narayan ◽  
Zhi-Kui Ling
Keyword(s):  
Engineering Design ◽  
Surface Finish ◽  
Feature Recognition ◽  
Graph Representation ◽  
Heuristic Rules ◽  
Feature Identification ◽  
Design And Manufacturing ◽  
Feature Based ◽  
Manufacturing Features

Abstract Feature based modeling has been used as a means to bridge the gap between engineering design and manufacturing. Features can represent an artifact with higher level entities which relate directly to its design functionalities and manufacturing characteristics, such as surface finish, manufacturability, fits, tolerance etc. In this study, a heuristic based feature recognition approach is proposed by using the graph representation of a design. The process consists of two steps: subgraph construction, and subgraph to feature identification. In this study, the subgraph construction is accomplished by using a set of heuristic rules. The process of subgraph to feature identification is carried out with a set of integers and characters which represent the geometric, topological, and semantic characteristics of the corresponding feature. This feature recognition scheme is used for the identification of machine features in a design.

Maximal Volume Decomposition and its Application to Feature Recognition

1995 ◽  
Author(s):  
Parag Dave ◽  
Hiroshi Sakurai
Keyword(s):  
Decomposition Method ◽  
Feature Recognition ◽  
Graph Matching ◽  
Raw Material ◽  
Maximal Volume ◽  
Object A ◽  
Finished Part ◽  
Volume Decomposition ◽  
Minimal Cells ◽  
Volume Difference

Abstract A method has been developed that decomposes an object having both planar and curved faces into volumes, called maximal volumes, using the halfspaces of the object. A maximal volume has as few concave edges as possible without introducing additional halfspaces. The object is first decomposed into minimal cells by extending the faces of the object. These minimal cells are then composed to form maximal volumes. The combinations of such minimal cells that result in maximal volumes are searched efficiently by examining the relationships among those minimal cells. With this decomposition method, a delta volume, which is the volume difference between the raw material and the finished part, is decomposed into maximal volumes. By subtracting maximal volumes from each other in different orders and applying graph matching to the resulting volumes, multiple interpretations of features can be generated.

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