Constructive Representation of Heterogeneous Objects

2001 ◽  
Vol 1 (3) ◽  
pp. 205-217 ◽  
Author(s):  
Ki-Hoon Shin ◽  
Debasish Dutta
Keyword(s):  
Data Structure ◽  
Material Composition ◽  
Binary Trees ◽  
Heterogeneous Objects ◽  
Computer Representation ◽  
Model Hierarchy ◽  
Representation Scheme

This paper proposes a constructive representation scheme for heterogeneous objects (or FGMs). In particular, this scheme focuses on the construction of complicated heterogeneous objects, guaranteeing desired material continuities at all the interfaces. In order to create various types of heterogeneous primitives, we first describe methods for specifying material composition functions such as geometry-independent, geometry-dependent functions, and multiple sets of these functions. Constructive Material Composition (CMC) and corresponding heterogeneous Boolean Operators (e.g., material union, difference, intersection, and partition) are then proposed to illustrate how material continuities are dealt with. Finally, we will describe the model hierarchy and data structure for computer representation. Even though the constructive representation alone is sufficient for modeling heterogeneous objects, the proposed scheme pursues a hybrid representation between decomposition and construction. That is because hybrid representation can avoid unnecessary growth of binary trees.

Point Clouds Based Dynamical Representation for Heterogeneous Objects

2012 ◽  
Vol 476-478 ◽  
pp. 1291-1296
Author(s):  
Jing Bo Li ◽  
Ji Quan Yang ◽  
Jian Ping Shi
Keyword(s):  
Volume Fraction ◽  
Point Clouds ◽  
Material Composition ◽  
Layer By Layer ◽  
Numerical Examples ◽  
Material Layer ◽  
Distribution Property ◽  
Heterogeneous Objects ◽  
Irregular Mesh ◽  
Distribution Vector

An approach of point clouds based dynamical representation for Heterogeneous Objects (HEO) is proposed to describe the HEO, in which materials distribution is uniformed or irregular. Mesh refined STL model and micro-tetrahedral cell are employed to rebuild HEO geometry. Meanwhile, distribution property, volume fraction and distribution vector are used to represent material features of HEO nodes within each material layer. Therefore, after implementing the above interrogation process layer by layer, HEO geometry and material composition representation can be defined. The approach is effective and practicable through some numerical examples demonstrated based on developed HEO fabrication system.

Physics Based B-Spline Heterogeneous Object Modeling

2001 ◽  
Author(s):  
Xiaoping Qian ◽  
Debasish Dutta
Keyword(s):  
Diffusion Process ◽  
Material Properties ◽  
Degrees Of Freedom ◽  
Heterogeneous Material ◽  
Critical Issue ◽  
Material Composition ◽  
B Spline ◽  
Material Heterogeneity ◽  
Heterogeneous Objects ◽  
Modeling Material

Abstract The task of modeling material heterogeneity (composition variation) is a critical issue in the design and fabrication of heterogeneous objects. Existing methods cannot efficiently model the material heterogeneity, due to the formidable size of the degrees of freedom for the specification of heterogeneous objects. In this research, we provide an intuitive way to model the object heterogeneity by using only a few parameters. These parameters carry physical meanings, such as diffusion coefficients in the diffusion process. We use a B-spline representation to model heterogeneous objects and material properties. We use diffusion equations to generate heterogeneous material composition profile. We then use finite element techniques to solve the material composition equations for the diffusion process. Finally we extend this method to the direct manipulation of material properties in heterogeneous objects.

An Integrated Design and Fabrication Approach for Heterogeneous Objects

2011 ◽  
Vol 383-390 ◽  
pp. 5810-5817 ◽  
Author(s):  
Yu Fang Zhu ◽  
Chen Peng ◽  
Ji Quan Yang ◽  
Chang Ming Wang
Keyword(s):  
Three Dimensional ◽  
Integrated Design ◽  
Working Process ◽  
Stl Model ◽  
Three Dimensional Printing ◽  
Heterogeneous Objects ◽  
New Process ◽  
Novel Method ◽  
Representation Scheme ◽  
Dimensional Printing

A novel method for the design and fabrication of heterogeneous objects is presented, which combines the Three Dimensional Printing (3DP) and micro droplets dispensing technology. It provides a solution to the fabrication of assemblies with multi materials, which can not be fabricated by traditional processes. An integrated design and fabrication system for heterogeneous objects based on the new process is introduced. Its constructive representation scheme is described. To show the effectiveness of the working process of multi-materials, based on slice software of color STL model and developing prototyping system, an example is shown to illustrate the entire design-fabrication cycle for heterogeneous objects.

scholarly journals Modelling multiply connected heterogeneous objects using mixed-dimensional material reference features

2018 ◽  
Vol 6 (3) ◽  
pp. 337-347 ◽  
Author(s):  
G.K. Sharma ◽  
B. Gurumoorthy
Keyword(s):  
Ab Initio ◽  
High Performance ◽  
Complex Geometry ◽  
Medial Axis ◽  
High Hardness ◽  
Material Composition ◽  
Material Distribution ◽  
Heterogeneous Objects ◽  
Form Features ◽  
General Method

Abstract This paper proposes a general method for ab-initio modelling and representation of heterogeneous objects that are associated with complex material variation over complex geometry. Heterogeneous objects like composites and naturally occurring objects (bones, rocks and meteorites) possess multiple and often conflicting properties (like high hardness and toughness simultaneously), which are associated with random and irregular material distribution. Modelling such objects is desired for numerical analysis and additive manufacturing to develop bio-implants, high-performance tools etc. However, it is difficult to define and map the arbitrary material distribution within the object as the material distribution can be independent of the shape parameters or form features used to construct its solid model. This paper represents the source of random and irregular material distribution by mixed-dimensional entities with a focus on modelling compositional heterogeneity. The domain of effect of each material reference entity is defined automatically by using Medial Axis Transform (MAT), where the material distribution can be intuitively prescribed, starting from the material reference entity and terminating at the medial axis segment bounding the corresponding domain. Within such a domain, the spatial variation of the material is captured by a distance field from the material reference entity, which can be controlled locally and independently. These domains are stored using the neighbourhood relation for efficient operations like altering material distribution across the material reference entity and material evaluation for a given geometric location. Results from an implementation for 2.5D objects are shown and the extension to 3D objects is discussed. Highlights Hybrid representation for complex heterogeneous objects. General method for ab-initio modelling of complex heterogeneous objects capture arbitrary material distribution by automatic domain decomposition. Local control of material composition through MAT around material feature. Specification of material composition without adding new entities to shape model.

scholarly journals Iso-material contour representation for process planning of heterogeneous object model

2020 ◽  
Vol 7 (4) ◽  
pp. 498-513
Author(s):  
G K Sharma ◽  
B Gurumoorthy
Keyword(s):  
Additive Manufacturing ◽  
Material Composition ◽  
Composition Material ◽  
Object Model ◽  
Material Distribution ◽  
Process Plan ◽  
Contour Representation ◽  
Heterogeneous Objects ◽  
Raster Scan ◽  
Heterogeneous Object

Abstract Additive manufacturing is emerging as the preferred process for making heterogeneous objects. Planning the deposition of material is more complex for heterogeneous objects as the material variation has to be tracked along the path. This paper proposes an iso-material contour representation to generate the process plan for additive manufacturing given a smooth representation of heterogeneous object model. These contours represent the iso-material paths for deposition. As these paths shift along the direction of the gradation of material distribution, the deposition respects the gradient of the designed material distribution unlike iso-oriented paths generated by a raster scan method. Since the paths have the same material composition, material frequent change in the material composition is avoided, which, in turn, avoids the uneven deposition caused by the frequent start and stop of deposition while the material is being changed along the paths generated by the traditional raster scan. Associativity between the contours and the corresponding designed material feature is maintained, and therefore, changes in material composition are automatically propagated to the process plan.

Heterogeneous Object Modeling Approach Based on ACIS and HOOPS

2009 ◽  
Vol 419-420 ◽  
pp. 793-796
Author(s):  
An Ping Xu ◽  
Ting Zang ◽  
Zhen Peng Ji ◽  
Yun Xia Qu
Keyword(s):  
Inverse Distance Weighting ◽  
Material Composition ◽  
Functional Modules ◽  
Object Modeling ◽  
Modeling Approach ◽  
Heterogeneous Objects ◽  
Distance Weighting ◽  
Heterogeneous Object ◽  
Heterogeneous Object Modeling ◽  
Inverse Distance

This paper deals with the background and significance of working on heterogeneous objects modeling and briefly introduces the architecture of ACIS and HOOPS and their corresponding functional modules. Based on inverse-distance weighting algorithm to determine the material composition within the object, the general approach to modeling the heterogeneous objects by using ACIS and HOOPS is introduced and demonstrated via some simple examples.

Introducing Data Structures for Big Data

2016 ◽  
pp. 25-52 ◽  
Author(s):  
Ranjit Biswas
Keyword(s):  
Big Data ◽  
Data Structure ◽  
Data Structures ◽  
Binary Tree ◽  
Data Science ◽  
Heterogeneous Data ◽  
Binary Trees ◽  
Homogeneous Trees ◽  
The Subject ◽  
Homogeneous Data

The homogeneous data structure ‘train' and the heterogeneous data structure ‘atrain' are the fundamental, very powerful dynamic and flexible data structures, being the first data structures introduced exclusively for big data. Thus ‘Data Structures for Big Data' is to be regarded as a new subject in Big Data Science, not just as a new topic, considering the explosive momentum of the big data. Based upon the notion of the big data structures train and atrain, the author introduces the useful data structures for the programmers working with big data which are: homogeneous stacks ‘train stack' and ‘rT-coach stack', heterogeneous stacks ‘atrain stack' and ‘rA-coach stack', homogeneous queues ‘train queue' and ‘rT-coach queue', heterogeneous queues ‘atrain queue' and ‘rA-coach queue', homogeneous binary trees ‘train binary tree' and ‘rT-coach binary tree', heterogeneous binary trees ‘atrain binary tree' and ‘rA-coach binary tree', homogeneous trees ‘train tree' and ‘rT-coach tree', heterogeneous trees ‘atrain tree' and ‘rA-coach tree', to enrich the subject ‘Data Structures for Big Data' for big data science.

Tolerance Representation Scheme in Solid Model: Part II

1989 ◽  
Author(s):  
U. Roy ◽  
K. Mantooth ◽  
M. D. Pollard ◽  
C. R. Liu
Keyword(s):  
Data Structure ◽  
Data Models ◽  
Solid Model ◽  
Essential Information ◽  
Interactive Environment ◽  
Representation Scheme ◽  
Set Operation

Abstract Tolerance representation in a CAD data structure demands a user interactive environment which enables the user to input the tolerance information in both the unevaluated (CSG) and in the evaluated (B-Rep) databases [4]. This requires an effective linking mechanism between the CSG and the B-Rep data models at each stage of the object development. This has been achieved through the development of a reference face list. Tolerance information has been attached with this face list as “constraint nodes,” which are formed and updated after each “set operation.” Several functions have also been developed to retrieve essential information from the data structure in order to answer various queries.

H-ISM: An Implementation of Heterogeneous Implicit Solid Modeling

2002 ◽  
Author(s):  
Justin Wahlborg ◽  
Mark A. Ganter ◽  
Daniel T. Schwartz ◽  
Duane Storti
Keyword(s):  
Computer Algebra ◽  
Computer Algebra System ◽  
Solid Modeling ◽  
Material Composition ◽  
Material Objects ◽  
Related Literature ◽  
Standard Part ◽  
Heterogeneous Objects ◽  
Solid Models ◽  
Implicit Solid

This paper discusses implementation of an implicit solid modeling approach to the representation of heterogeneous objects, i.e. solids whose material composition is not uniform. We present a brief review of related literature and then focus on implementation of heterogeneous implicit solid modeling (H-ISM) using a computer algebra system. Several heterogeneous implicit solid models of multi-material objects from standard part catalogues are presented to demonstrate the effectiveness of H-ISM implementation.

Sign in / Sign up

Export Citation Format

Share Document