The Rigid Origami Patterns for Flat Surface

2013 ◽  
Author(s):  
Sicong Liu ◽  
Yan Chen ◽  
Guoxing Lu
Keyword(s):  
Flat Surface ◽  
Kinematic Model ◽  
Simulation Models ◽  
Compatibility Conditions ◽  
Engineering Applications ◽  
Internal Mobility ◽  
Mobile Processes ◽  
Geometric Compatibility

Because of the internal mobility, rigid origami structures have great potential in engineering applications. In this research, a kinematic model of the rigid origami pattern is proposed based on the assembly of spherical 4R linkages. To ensure the rigid origami pattern with mobility one, the kinematic and geometric compatibility conditions of the kinematic model are derived. Four types of flat rigid origami patterns are obtained, including three existing types as well as a novel one called the supplementary type. To testify and display the mobile processes of the patterns, their simulation models are built accordingly.

Deployable Prismatic Structures With Origami Patterns

2014 ◽  
Author(s):  
Sicong Liu ◽  
Weilin Lv ◽  
Yan Chen ◽  
Guoxing Lu
Keyword(s):  
Design Method ◽  
Kinematic Model ◽  
The Other ◽  
Dihedral Angles ◽  
Geometric Condition ◽  
Compatibility Conditions ◽  
Deployable Structures ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Geometric Compatibility

In order to find the general condition of the rigid origami pattern for the deployable prismatic structures, the kinematic model is proposed based on the mobile assemblies of spherical 4R linkages. The kinematic and geometric compatibility conditions of the mobile assemblies are derived. Two groups of 2n-side deployable prismatic structures are obtained. When n=2, one of them is with kite-shape intersection, while the other is with parallelgram. The variations of the unit are discussed. The straight and curvy multilayer prisms are built by changing the dihedral angles between the intersecting planes. The general design method for the 2n-side multilayer deployable prismatic structures is proposed with the geometric condition of the origami patterns. All the deployable structures constructed with this method can be deployed and folded along the central axis of the prisms with single degree of freedom, which makes the structures have wide engineering applications.

The Role of Smart Technologies to Improve the Utilization of Wood Uses in Engineering Applications: A Review

2021 ◽  
Vol 43 ◽  
pp. 123-136
Author(s):  
Salah Hamed Ramadan Ali ◽  
Gehan A. Ebrahim
Keyword(s):  
Simulation Models ◽  
Engineering Applications ◽  
Vehicle Simulation ◽  
Measurement Systems ◽  
Current Path ◽  
Smart Technologies ◽  
Strength And Durability ◽  
Scientific Treatment

Nowadays, smart technology plays an important role in engineering applications to improve the quality of life. Thus, the development of natural materials and the use of nanotechnology, will give wood new properties to maximize its benefit. It is clear that there is a great challenge to prove the strength and durability of wood acquiring new features to reach innovative use that can influence the current path in many engineering applications. Therefore, this paper summarizes a review of the possibility of using nano- and smart-technologies to make the most of the natural and acquired potential for adding new features and physical properties of wood to improve its efficiency in architectural and mechanical applications. Moreover, experiments have shown that the use of certain types of wood in many applications such as the manufacture of 3D vehicle simulation models to study dynamic behaviors as well as in the manufacture of mechanical measurement systems to improve accuracy. In conclusion, new directions under development in this field are proposed to provide solutions to important issues in the future of measurement and quality control systems that need scientific treatment.--

Deployable Prismatic Structures With Rigid Origami Patterns

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Sicong Liu ◽  
Weilin Lv ◽  
Yan Chen ◽  
Guoxing Lu
Keyword(s):  
Closed Loop ◽  
Design Method ◽  
Kinematic Model ◽  
Deployable Structures ◽  
Engineering Applications ◽  
Single Degree Of Freedom ◽  
General Design ◽  
Plane Symmetric ◽  
Single Degree ◽  
Spherical Linkages

Rigid origami inspires new design technology in deployable structures with large deployable ratio due to the property of flat foldability. In this paper, we present a general kinematic model of rigid origami pattern and obtain a family of deployable prismatic structures. Basically, a four-crease vertex rigid origami pattern can be presented as a spherical 4R linkage, and the multivertex patterns are the assemblies of spherical linkages. Thus, this prismatic origami structure is modeled as a closed loop of spherical 4R linkages, which includes all the possible prismatic deployable structures consisting of quadrilateral facets and four-crease vertices. By solving the compatibility of the kinematic model, a new group of 2n-sided deployable prismatic structures with plane symmetric intersections is derived with multilayer, straight and curvy variations. The general design method for the 2n-sided multilayer deployable prismatic structures is proposed. All the deployable structures constructed with this method have single degree-of-freedom (DOF), can be deployed and folded without stretching or twisting the facets, and have the compactly flat-folded configuration, which makes it to have great potential in engineering applications.

The Wrinkled Axisymmetric Air Bags Made of Inextensible Membrane

1974 ◽  
Vol 41 (4) ◽  
pp. 963-968 ◽  
Author(s):  
Chien H. Wu
Keyword(s):  
Principal Stress ◽  
Governing Equation ◽  
Elliptic Integral ◽  
Compatibility Conditions ◽  
Air Bags ◽  
Stress Resultant ◽  
Air Bag ◽  
Geometric Compatibility

The wrinkling phenomenon is a consequence of the presence of a negative principal stress resultant. This condition, together with certain geometric compatibility conditions, is used to determine the locations and geometry of wrinkled zones. The governing equation is nonlinear but can be reduced to a quadrature. The shape of the air bag without azimuthal stress resultant is determined in terms of an elliptic integral.

Scanned tip measurement of deep vertical facets on a flat surface: Measuring roughness on gaas laser waveguide mirrors

1993 ◽  
Vol 51 ◽  
pp. 532-533
Author(s):  
Chang Shen ◽  
Phil Fraundorf ◽  
Robert W. Harrick
Keyword(s):  
Integrated Circuits ◽  
Flat Surface ◽  
Scanning Force Microscopy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Optoelectronic Integrated Circuits ◽  
Laser Waveguide ◽  
Scanning Force ◽  
Gaas Laser

Monolithic integration of optoelectronic integrated circuits (OEIC) requires high quantity etched laser facets which prevent the developing of more-highly-integrated OEIC's. The causes of facet roughness are not well understood, and improvement of facet quality is hampered by the difficulty in measuring the surface roughness. There are several approaches to examining facet roughness qualitatively, such as scanning force microscopy (SFM), scanning tunneling microscopy (STM) and scanning electron microscopy (SEM). The challenge here is to allow more straightforward monitoring of deep vertical etched facets, without the need to cleave out test samples. In this presentation, we show air based STM and SFM images of vertical dry-etched laser facets, and discuss the image acquisition and roughness measurement processes. Our technique does not require precision cleaving. We use a traditional tip instead of the T shape tip used elsewhere to preventing “shower curtain” profiling of the sidewall. We tilt the sample about 30 to 50 degrees to avoid the curtain effect.

Calculation of many-beam dynamic electron diffraction without high-energy approximation

1996 ◽  
Vol 54 ◽  
pp. 128-129
Author(s):  
B. R. Ahn ◽  
N. J. Kim
Keyword(s):  
Electron Diffraction ◽  
Flat Surface ◽  
Dynamic Theory ◽  
High Energy ◽  
Perfect Crystal ◽  
Zone Axis ◽  
Beam Dynamic ◽  
Diffraction Angle ◽  
Energy Approximation ◽  
The Many

High energy approximation in dynamic theory of electron diffraction involves some intrinsic problems. First, the loss of theoretical strictness makes it difficult to comprehend the phenomena of electron diffraction. Secondly, it is difficult to believe that the approximation is reasonable especially in the following cases: 1) when accelerating voltage is not sufficiently high, 2) when the specimen is thick, 3) when the angle between the surface normal of the specimen and zone axis is large, and 4) when diffracted beam with large diffraction angle is included in the calculation. However, until now the method to calculate the many beam dynamic electron diffraction without the high energy approximation has not been proposed. For this reason, the authors propose a method to eliminate the high energy approximation in the calculation of many beam dynamic electron diffraction. In this method, a perfect crystal with flat surface was assumed. The method was applied to the calculation of [111] zone axis CBED patterns of Si.

Correlation of Pore Structure and Permeability by SEM-Image Analysis

1990 ◽  
Vol 48 (1) ◽  
pp. 428-429
Author(s):  
C. A. Callender ◽  
Wm. C. Dawson ◽  
J. J. Funk
Keyword(s):  
Image Analysis ◽  
Pore Structure ◽  
Imaging System ◽  
Pore Space ◽  
Simulation Models ◽  
Image Analyzer ◽  
Imaging Data ◽  
Sem Images ◽  
Thin Sections ◽  
Rock Types

The geometric structure of pore space in some carbonate rocks can be correlated with petrophysical measurements by quantitatively analyzing binaries generated from SEM images. Reservoirs with similar porosities can have markedly different permeabilities. Image analysis identifies which characteristics of a rock are responsible for the permeability differences. Imaging data can explain unusual fluid flow patterns which, in turn, can improve production simulation models.Analytical SchemeOur sample suite consists of 30 Middle East carbonates having porosities ranging from 21 to 28% and permeabilities from 92 to 2153 md. Engineering tests reveal the lack of a consistent (predictable) relationship between porosity and permeability (Fig. 1). Finely polished thin sections were studied petrographically to determine rock texture. The studied thin sections represent four petrographically distinct carbonate rock types ranging from compacted, poorly-sorted, dolomitized, intraclastic grainstones to well-sorted, foraminiferal,ooid, peloidal grainstones. The samples were analyzed for pore structure by a Tracor Northern 5500 IPP 5B/80 image analyzer and a 80386 microprocessor-based imaging system. Between 30 and 50 SEM-generated backscattered electron images (frames) were collected per thin section. Binaries were created from the gray level that represents the pore space. Calculated values were averaged and the data analyzed to determine which geological pore structure characteristics actually affect permeability.

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