Destructive Modeling by Volume Decomposition and Its Applications

Author(s):  
Yoonhwan Woo ◽  
Sang Hun Lee

Adding simple volumes, which are often called primitives, is a natural way to construct complex solid models. Conversely, cell-based volume decomposition is the existing method to decompose a complex solid model into simpler volumes that are often the primitives used to create the model. One problem of this volume decomposition is that it generates a large number of cells, many of which are unnecessary for the decomposition. In this paper, a volume decomposition method that improves the performance by avoiding generating the unnecessary cells is presented. Some possible applications are also presented to attest the usefulness of this volume decomposition method.

Author(s):  
Bih-Yaw Shih ◽  
Hiroshi Sakurai

Abstract A method has been developed to generate regular hexahedral meshes automatically from arbitrary solid models by volume decomposition. This method first decomposes a solid model having a complex shape into volumes having simple shapes. Then, shape-specific meshing methods like mapping are applied to generate regular hexahedral meshes from these volumes. Finally, all regular hexahedral meshes of these volumes are combined into a regular hexahedral mesh of the original solid model. Thus the method generates regular hexahedral meshes automatically in a way similar to the way a human does interactively. This is in contrast to the previous methods of automatic hexahedral mesh generation, which try to generate hexahedral meshes from solid models directly.


Author(s):  
Yan Shen ◽  
Jami J. Shah

Abstract A volume decomposition method called minimum convex decomposition by half space partitioning has been developed to recognize machining features from the boundary representation of the solid model. First, the total volume to be removed by machining is obtained by subtracting the part from the stock. This volume is decomposed into minimum convex cells by half space partitioning at every concave edge. A method called maximum convex cell composition is developed to generate all alternative volume decompositions. The composing sub volumes are classified based on degree of freedom analysis. This paper focuses on the first part of our system, i.e., the volume decomposition. The other part of the work will be submitted for publication at a leter date.


Author(s):  
S Chahardoli ◽  
Mohammad Sheikh Ahmadi ◽  
TN Tran ◽  
Afrasyab Khan

This study examined the effect of the upper surface slope and the number of cells in the side beams on the collapse properties using experimental and numerical tests. The numerical studies were conducted with LS-DYNA software, and the accuracy of numerical results was investigated by experimental tests. Using MATLAB software, the second-degree polynomial functions were obtained for the collapse properties of the specimens. Also, after the optimization by the decomposition method, the best mode was introduced for the specimens. The studies on collapse properties showed that increasing the number of cells leads to a decrease in all collapse properties, and increasing the upper surface slope leads to an increase in the collapse properties. Moreover, the optimization results by decomposition method showed that this method could suggest the most optimal model for multi-cell and sloping beams.


Author(s):  
Parag Dave ◽  
Hiroshi Sakurai

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.


Author(s):  
Carol Hubbard ◽  
Yong Se Kim

Abstract As the extensive use of solid models becomes widespread, it is important to have a mechanism by which existing engineering drawings can be converted into solid models. Therefore, a geometric assistant which can aid in the construction of solid models is beneficial. In this paper, we present key operations for a system called the Assistant for the Rapid Construction of Solids (ARCS), that provides this assistance given a set of two orthographic views. ARCS is based on the Visual Reasoning Tutor (VRT), a system we developed that provides users with the geometric framework to build polyhedral solids from their orthographic views. However, the geometric domain of ARCS encompasses non-polyhedral solids with cylindrical and spherical surfaces, such as those found in typical mechanical parts. We have devised the Cylindrical and Spherical Warping operations to create cylindrical and spherical surfaces, which use interactive computer graphics that guide a human user to build non-polyhedral faces of a solid. These operations are then illustrated with an example using ARCS to create the solid model of a typical mechanical part from its orthographic projections.


Author(s):  
Zahed Siddique ◽  
Jiju A. Ninan

Designing family of products require analysis and evaluation of performance for the entire product family. In the past, products were mainly mass-produced hence the use of CAD/CAE was restricted to developing and analyzing individual products. Since the products offered using a platform approach include a variety of products built upon a common platform, CAD/CAE tools need to be explored further to assist in customization of products according to the customer needs. In this paper we investigate the development of a Product Family FEA (PFFEA) module that can support FEA analysis of user customized product families members. Customer specifications for family members are gathered using the internet, users are allowed to scale and change configurations of products. These specifications are then used to automatically generate 3D solid models of the product and then perform FEA to determine feasibility of the customer specified product. In this paper, development of the PFFEA module is illustrated using a family of lawn trimmer and edger. The PFFEA module uses Pro/E to generate the solid model and ANSYS as the base FEA software.


Author(s):  
Di Wu ◽  
Swati Bhargava ◽  
Radha Sarma

Abstract This paper proposes an algorithm for streaming manifold solid models and NURBS geometry. A neutral streaming representation consisting of a nodes graph is encoded by a one-dimensional dynamic stack. The encoded model is transmitted over the Internet, where a two-dimensional dynamic stack decodes and reconstructs the solid model. The time and storage complexity of the algorithm are investigated. An example of streaming a solid model, resulting from a proof-of-concept implementation, is demonstrated.


2019 ◽  
Vol 17 (1) ◽  
pp. 232-241 ◽  
Author(s):  
Aktham E. Shoukry ◽  
Ahmed H. El-Banbi ◽  
Helmy Sayyouh

Abstract Cubic equation-of-state solid models are one of the most widely used models to predict asphaltene precipitation behavior. Thermodynamic parameters are needed to model precipitation under different pressures and temperatures and are usually obtained through tuning with multi asphaltene onset experiments. For the purpose of enhancing the cubic Peng–Robinson solid model and reducing its dependency on asphaltene experiments, this paper tests the use of aromatics and waxes correlations to obtain these thermodynamic parameters. In addition, weighted averages between both correlations are introduced. The averaging is based on reported saturates, aromatics, resins, asphaltene (SARA) fractions, and wax content. All the methods are tested on four oil samples, with previously published data, covering precipitation and onset experiments. The proposed wax-asphaltene average showed the best match with experimental data, followed by a SARA-weighted average. This new addition enhances the model predictability and agrees with the general molecular structure of asphaltene molecules.


Author(s):  
William W. Charlesworth ◽  
David C. Anderson

Abstract It is widely recognized that a solid model based on a non-manifold boundary representation can have a more complicated surface topology than one based on a manifold boundary representation, but non-manifold topology has other capabilities that may be more valuable to the application developer. Non-manifold topology can be put to use in existing application areas in ways that differ significantly from the techniques developed for manifold modeling and it can be put to use in new applications that have not been satisfactorily solved by manifold topology. Several applications of non-manifold topology that would be difficult or impossible to implement using a purely manifold geometric modeler are illustrated: automatic formulation of finite element analyses from solid models, automatic generation of machining tool paths for 2½-dimensional pockets, and construction of geometric models using topological constraints. These applications demonstrate how a non-manifold model partitions the entire space in which an object is embedded, preserves elements of the model that would be discarded by conventional schemes, and permits the implementation of a common merge operation. All three applications have been implemented using a two dimensional non-manifold (non-1-manifold) geometric modeler.


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