scholarly journals Geometric conditions for injectivity of 3D Bézier volumes

2021 ◽  
Vol 6 (11) ◽  
pp. 11974-11988
Author(s):  
Xuanyi Zhao ◽  
◽  
Jinggai Li ◽  
Shiqi He ◽  
Chungang Zhu ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Point Of View ◽  
Control Points ◽  
Positive Weight ◽  
Geometric Conditions ◽  
Geometric Point ◽  
Wide Range ◽  
The One ◽  
Deformation Models ◽  
Aided Design

<abstract><p>The one-to-one property of injectivity is a crucial concept in computer-aided design, geometry, and graphics. The injectivity of curves (or surfaces or volumes) means that there is no self-intersection in the curves (or surfaces or volumes) and their images or deformation models. Bézier volumes are a special class of Bézier polytope in which the lattice polytope equals $ \Box_{m, n, l}, (m, n, l\in Z) $. Piecewise 3D Bézier volumes have a wide range of applications in deformation models, such as for face mesh deformation. The injectivity of 3D Bézier volumes means that there is no self-intersection. In this paper, we consider the injectivity conditions of 3D Bézier volumes from a geometric point of view. We prove that a 3D Bézier volume is injective for any positive weight if and only if its control points set is compatible. An algorithm for checking the injectivity of 3D Bézier volumes is proposed, and several explicit examples are presented.</p></abstract>

scholarly journals Edge Models with the CAD Software: Creating a New Context for Mathematics in Elementary School

2021 ◽  
Author(s):  
Felicitas Pielsticker ◽  
Ingo Witzke ◽  
Amelie Vogler
Keyword(s):  
Elementary Schools ◽  
Digital Media ◽  
Computer Aided Design ◽  
Subjective Experience ◽  
Fourth Graders ◽  
Point Of View ◽  
Toulmin Model ◽  
Geometric Objects ◽  
Design Software ◽  
Aided Design

AbstractDigital media have become increasingly important in recent years and can offer new possibilities for mathematics education in elementary schools. From our point of view, geometry and geometric objects seem to be suitable for the use of computer-aided design software in mathematics classes. Based on the example of Tinkercad, the use of CAD software — a new and challenging context in elementary schools — is discussed within the approach of domains of subjective experience and the Toulmin model. An empirical study examined the influence of Tinkercad on fourth-graders’ development of a model of a geometric solid and related reasoning processes in mathematics classes.

scholarly journals Characterisation of the Filler Fraction in CAD/CAM Resin-Based Composites

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1986
Author(s):  
Andreas Koenig ◽  
Julius Schmidtke ◽  
Leonie Schmohl ◽  
Sibylle Schneider-Feyrer ◽  
Martin Rosentritt ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Point Of View ◽  
Specific Information ◽  
Dental Resin ◽  
X Ray ◽  
Computer Aided ◽  
Cad Cam ◽  
Filler Fraction ◽  
The Individual ◽  
Aided Design

The performance of dental resin-based composites (RBCs) heavily depends on the characteristic properties of the individual filler fraction. As specific information regarding the properties of the filler fraction is often missing, the current study aims to characterize the filler fractions of several contemporary computer-aided design/computer-aided manufacturing (CAD/CAM) RBCs from a material science point of view. The filler fractions of seven commercially available CAD/CAM RBCs featuring different translucency variants were analysed using Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS), Micro-X-ray Computed Tomography (µXCT), Thermogravimetric Analysis (TG) and X-ray Diffractometry (XRD). All CAD/CAM RBCs investigated included midifill hybrid type filler fractions, and the size of the individual particles was clearly larger than the individual specifications of the manufacturer. The fillers in Shofu Block HC featured a sphericity of ≈0.8, while it was <0.7 in all other RBCs. All RBCs featured only X-ray amorphous phases. However, in Lava Ultimate, zircon crystals with low crystallinity were detected. In some CAD/CAM RBCs, inhomogeneities (X-ray opaque fillers or pores) with a size <80 µm were identified, but the effects were minor in relation to the total volume (<0.01 vol.%). The characteristic parameters of the filler fraction in RBCs are essential for the interpretation of the individual material’s mechanical and optical properties.

Study on Application of CAD Used in Visual Advertising Design

2014 ◽  
Vol 571-572 ◽  
pp. 768-771
Author(s):  
Jun Liu
Keyword(s):  
Computer Aided Design ◽  
Television Advertising ◽  
Paper Study ◽  
Application Technology ◽  
Visual Effects ◽  
3D Technology ◽  
Wide Range ◽  
Computer Aided ◽  
Visual Impact ◽  
Aided Design

The 3D technology currently has in various engineering fields have a wide range of applications, all the 3D visual effects technology can bring us visual impact, the use of 3D technology produced by the television advertising more easily accepted by the audience, this paper study on the 3D computer-aided design advertising design application technology.

scholarly journals Simulation Study of a Composite Landig Gear of Ultralight and Very Light Aircraft

2021 ◽  
Author(s):  
Paulina Zenowicz
Keyword(s):  
Simulation Study ◽  
Computer Aided Design ◽  
Landing Gear ◽  
Design Tool ◽  
Drop Test ◽  
Environment Design ◽  
Element Analysis ◽  
Computer Methods ◽  
The One ◽  
Aided Design

There is a need to design new, lighter aircraft structures, which has a direct impact on the safety and costs of aircraft maintenance. One of basic parts of an aircraft is ites landing gear, whose main functions are to enable taxiing, safe landing, take-off, and to assist the remainder of ground operations. Landing gear failures are usually related to metallurgy, processing, environment, design, and causes of overload. These are conditions that can be prevented using modern methods to calculate the strength of such a landing gear in various conditions. The paper presents stages of a simulation study of the fixed three-wheeled spring landing gear for an ultralight aircraft. Analysis of forces acting on the landing gear during drop test and their implementation by numerical computer methods allowed for the creation of a model in the CAD (Computer-Aided Design) tool and its FEA (Finite Element Analysis). These results were compared between a modeled classic spring landing gear and the one made of composite materials. The further goal of the research will be to build a drop test stand for a small landing gear used in airplanes and drones. This method has a significant impact on simplifying the design of the landing gear, its modeling, and optimization.

Design and Mobility Analysis of Large Deployable Mechanisms Based on Plane-Symmetric Bricard Linkage

2016 ◽  
Author(s):  
Xiaozhi Qi ◽  
Bing Li ◽  
Zhihuai Miao ◽  
Hailin Huang
Keyword(s):  
Computer Aided Design ◽  
Closed Loop ◽  
Degree Of Freedom ◽  
Mobility Analysis ◽  
Plane Symmetric ◽  
Analysis And Design ◽  
Geometric Conditions ◽  
Deployable Mechanism ◽  
Vertical Bars ◽  
Aided Design

In this paper, a class of large deployable mechanisms constructed by plane-symmetric Bricard linkage is presented. The plane-symmetric Bricard linkage is a closed-loop over-constrained spatial mechanism composed of six hinge-jointed bars, which has one plane of symmetry during its deployment process. The kinematic analysis of the linkage is presented from the perspectives of geometric conditions, closure equations and degree of freedom. The results illustrates that the linkage has one degree of freedom, and it can be deployed from the folded configuration to one rectangle plane. Therefore, the plane-symmetric Bricard linkage can be used to construct lager deployable mechanism as basic deployable unit. Four plane-symmetric Bricard linkages can be assembled to a quadrangular module by sharing the vertical bars of adjacent units. The module is a multi-loop deployable mechanism and has one degree of freedom by the mobility analysis. Large deployable mast, deployable plane truss and deployable ring are built by a plurality of plane-symmetric Bricard linkages. The computer-aided design models for typical examples are built to illustrate their feasibility and validate the analysis and design methods.

Effects of Immersion on Virtual Reality Prototype Design Reviews of Mechanical Assemblies

2018 ◽  
Author(s):  
Luis de Casenave ◽  
José E. Lugo
Keyword(s):  
Computer Aided Design ◽  
Virtual Prototype ◽  
Point Of View ◽  
Human Computer Interface ◽  
Design Decisions ◽  
Mechanical Assemblies ◽  
Accurate Design ◽  
Virtual Prototypes ◽  
Aided Design ◽  
Prototype Design

The proficiency of Computer Aided Design (CAD) to save, communicate and render realistic virtual prototypes allows for easier communication and review of proposed design decisions via design reviews. However, the use of virtual prototypes is limited by the realism of the human computer interface. This paper builds on previous research investigating if increasing the realism of input and output interactions between subjects and virtual prototypes will affect user’s ability to analyze an assembly for errors. For this end, two experiments were conducted which asked participants to perform design reviews on assembly models and identify errors in the assembly. The first experiment tested virtual prototype output display factors through subject point of view movement and virtual prototype rotation. The second experiment tested human input factors using different controller setups. It is expected the more realistic virtual prototype rendering and controller input experience will result in more accurate design reviews.

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.

Towards Computer Aided Design and Analysis of Spatial Flexure Mechanisms

2016 ◽  
Author(s):  
Omer Anil Turkkan ◽  
Hai-Jun Su
Keyword(s):  
Computer Aided Design ◽  
Screw Theory ◽  
Design Tool ◽  
Future Design ◽  
Linear Elastic ◽  
Wide Range ◽  
Speed Up ◽  
System Equations ◽  
Compliance Matrices ◽  
Aided Design

Flexure mechanisms are the central part of numerous precision instruments and devices that are used in a wide range of science and engineering applications and currently, design of flexure mechanisms often heavily relies on designers’ previous hands-on experience. Therefore, a design tool that will speed up the design process is needed and this paper will introduce a systematic approach for building the necessary equations that are based on screw theory and linear elastic theory to analyze flexure mechanisms. A digital library of commonly used flexure elements must be available for a design tool and therefore, we first present the compliance matrices of commonly used flexure components. Motion twists and force wrenches of the screw theory can be related with these compliance matrices. Then, we introduce an algorithm that constructs the required linear system equations from individual compliance equations. This algorithm is applicable to flexure mechanisms with serial, parallel or hybrid chains. Finally, the algorithm is tested with a flexure mechanisms and it is shown that this approach can be the core of a future design tool.

Technology Education in the Middle Level School: Its Role and Purpose

1999 ◽  
Vol 83 (608) ◽  
pp. 34-44 ◽  
Author(s):  
Mark E. Sanders
Keyword(s):  
Technology Education ◽  
Computer Aided Design ◽  
World Wide ◽  
Magnetic Levitation ◽  
Education Technology ◽  
Middle Level ◽  
Digital Electronics ◽  
Flight Simulators ◽  
Wide Range ◽  
Aided Design

The curriculum and method of technology education remain one of the best-kept secrets in all education. Technology education engages students in a wide range of the very latest technologies: digital imaging, lasers, robotics, solar energy, World Wide Web development, magnetic levitation vehicles, analog and digital electronics, flight simulators, computer-aided design, and so forth.

Vertical tail FEA with a CAD/CAE based multidisciplinary process

2018 ◽  
Vol 90 (4) ◽  
pp. 652-658
Author(s):  
Péter Deák
Keyword(s):  
Finite Element ◽  
Computer Aided Design ◽  
Tail Length ◽  
Element Model ◽  
Point Of View ◽  
Content Type ◽  
Nodal Displacements ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Aided Design

Purpose The purpose of this paper is to make an analytical comparison of two vertical tail models from a structural point of view. Design/methodology/approach The original vertical tail design of PZL-106BT aircraft was used for Computer aided design (CAD) modeling and for creating the finite element model. Findings The nodal displacements, Von-Mises stresses and Buckling factors for two vertical tail models have been found using the finite element method. The idea of a possible Multidisciplinary concept assessment and design (MDCAD) concept was presented. Practical implications The used software analogy introduces an idea of having an automated calculation procedure within the framework of MDCAD. Originality/value The aircraft used for calculation had undergone a modification in its vertical tail length, as there was an urgent need to calculate for the plane’s manufacturer, PZL Warszawa – Okecie.

Sign in / Sign up

Export Citation Format

Share Document