scholarly journals Forming three-dimensional closed shapes from two-dimensional soft ribbons by controlled buckling

2018 ◽  
Vol 5 (2) ◽  
pp. 171962 ◽  
Author(s):  
Michio Aoki ◽  
Jia-Yang Juang
Keyword(s):  
Three Dimensional ◽  
Quantitative Agreement ◽  
Two Dimensional ◽  
Element Analysis ◽  
Hollow Structures ◽  
Strategic Design ◽  
Post Buckling ◽  
Manufacturing Techniques ◽  
New Applications ◽  
3D Shapes

Conventional manufacturing techniques—moulding, machining and casting—exist to produce three-dimensional (3D) shapes. However, these industrial processes are typically geared for mass production and are not directly applicable to residential settings, where inexpensive and versatile tools are desirable. Moreover, those techniques are, in general, not adequate to process soft elastic materials. Here, we introduce a new concept of forming 3D closed hollow shapes from two-dimensional (2D) elastic ribbons by controlled buckling. We numerically and experimentally characterize how the profile and thickness of the ribbon determine its buckled shape. We find a 2D master profile with which various elliptical 3D shapes can be formed. More complex natural and artificial hollow shapes, such as strawberry, hourglass and wheel, can also be achieved via strategic design and pattern engraving on the ribbons. The nonlinear response of the post-buckling regime is rationalized through finite-element analysis, which shows good quantitative agreement with experiments. This robust fabrication should complement conventional techniques and provide a rich arena for future studies on the mechanics and new applications of elastic hollow structures.

Three-dimensional deformations in a single-lap joint

1994 ◽  
Vol 29 (2) ◽  
pp. 137-145 ◽  
Author(s):  
M Y Tsai ◽  
J Morton
Keyword(s):  
Three Dimensional ◽  
Two Dimensional ◽  
Stress Distributions ◽  
Lap Joint ◽  
Displacement Fields ◽  
Element Analysis ◽  
Linear Elastic ◽  
Non Linear ◽  
Linear Effects ◽  
Peel Stress

The three-dimensional nature of the state of deformation in a single-lap test specimen is investigated in a linear elastic finite element analysis in which the boundary conditions account for the geometrically non-linear effects. The validity of the model is demonstrated by comparing the resulting displacement fields with those obtained from a moiré inteferometry experiment. The three-dimensional adherend and adhesive stress distributions are calculated and compared with those from a two-dimensional non-linear numerical analysis, Goland and Reissner's solution, and experimental measurements. The nature of the three-dimensional mechanics is described and discussed in detail. It is shown that three-dimensional regions exists in the specimen, where the adherend and adhesive stress distributions in the overlap near (and especially on) the free surface are quite different from those occurring in the interior. It is also shown that the adhesive peel stress is extremely sensitive to this three-dimensional effect, but the adhesive shear is not. It is also observed that the maximum value of the peel stress occurs at the end of the overlap in the central two-dimensional core region, rather than at the corners where the three-dimensional effects are found. The extent of three-dimensional regions is also quantified.

Post-Buckling Behavior of Z-Shaped Columns under Variables of Lengths and Initial Imperfections

2013 ◽  
Vol 437 ◽  
pp. 62-65
Author(s):  
Ji Nao Zhang
Keyword(s):  
Failure Modes ◽  
Control Method ◽  
Three Dimensional ◽  
Initial Imperfection ◽  
Maximum Load ◽  
Element Analysis ◽  
Initial Imperfections ◽  
Solution Methods ◽  
Post Buckling ◽  
Displacement Control Method

This paper conducts three-dimensional, nonlinear finite element analysis to investigate the results of using different solution methods and the influence of initial imperfections and material plasticity on failure modes and maximum load of various Z-shaped column lengths; it also compares the column buckling responses between various lengths, each with different initial imperfections. Further analyses include investigating the element suitability and computational costs. Results showed that both displacement control method and Riks method are fully capable of receiving promising results from this analysis. In terms of the effects of initial imperfection and material plasticity on the maximum load that column could carry, the imperfection is the major contributing factor when the column is long whereas the plasticity is the major contributing factor when the column is short.

THREE DIMENSIONAL FINITE ELEMENT SIMULATION OF THE FRETTING WEAR PROBLEMS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3890-3895 ◽  
Author(s):  
CHOON YEOL LEE ◽  
JOON WOO BAE ◽  
BYUNG SUN CHOI ◽  
YOUNG SUCK CHAI
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Fretting Wear ◽  
Symmetric Model ◽  
Two Dimensional ◽  
Element Analysis ◽  
Inconel 690 ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The structural integrity of steam generators in nuclear power plants is very much dependent upon the fretting wear characteristics of Inconel 690 U-tubes. In this study, a finite element analysis was used to investigate fretting wear on the secondary side of the steam generator, which arises from flow-induced vibrations (FIV) between the U-tubes and supports or foreign objects. Two-dimensional and three-dimensional finite element analyses were adopted to investigate the fretting wear problems. The purpose of the two-dimensional analysis, which simulated the contact between a punch and a plate, was to demonstrate the validity of using finite element analysis to analyze fretting wear problems. This was achieved by controlling the value of the wear constant and the number of cycles. The two-dimensional solutions obtained from this study were in good agreement with previous results reported by Strömberg. In the three-dimensional finite element analysis, a quarterly symmetric model was used to simulate tubes contacting at right angles. The results of the analyses showed donut-shaped wear along the contacting boundary, which is a typical feature of fretting wear.

Finite-element analysis of axi-symmetric rotors

1969 ◽  
Vol 4 (3) ◽  
pp. 163-168
Author(s):  
H Stordahl ◽  
H Christensen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Engineering Problems ◽  
Symmetric Rotor ◽  
Practical Engineering ◽  
Element Method

The finite-element method (1) (2)∗ is increasingly used in the stress analysis of mechanical-engineering problems. It is the purpose of this paper to described how the finite-element method can be used as an effective tool in the design of rotors. Up to the present time this method has mainly been used in the analysis of two-dimensional problems. However, a special class of three-dimensional problems, namely axi-symmetric rotors, can be treated as a nearly two-dimensional problem. This paper summarizes the development of the finite-element method as applied to the analysis of the axi-symmetric rotor. A computer programme is then briefly described, and the application of the method to the solution of three examples taken from practical engineering experience are presented.

Three-dimensional visibility graph analysis and its application

2017 ◽  
Vol 46 (5) ◽  
pp. 948-962 ◽  
Author(s):  
Yi Lu ◽  
Zhonghua Gou ◽  
Yu Ye ◽  
Qiang Sheng
Keyword(s):  
Three Dimensional ◽  
Urban Environments ◽  
Visibility Graph ◽  
Graph Analysis ◽  
Two Dimensional ◽  
Spatial System ◽  
Floor Plans ◽  
Graph System ◽  
New Applications ◽  
Visibility Graph Analysis

Graph-based visibility analysis, developed from space syntax and social network theory, embraces mutual visibility between locations in a spatial system. It helps designers and researchers to decode spatial cognition and behavior, but methodological constraints limit its application to two-dimensional floor plans. In this study, we propose a new visibility graph analysis that can be used in three-dimensional built environments, such as multilevel atrium buildings or urban environments with canopies or overpass bridges. Furthermore, we draw a distinction between a generic visibility graph and a targeted visibility graph. In the former, an occupiable location is considered as both the origin and target of visibility lines. In the latter, we further take into account the visible space or specific targets in a system. Visible locations are spaces people can see but cannot necessarily physically occupy. With this differentiation, the visibility graph system is more amenable to new applications in three-dimensional architectural and urban design while retaining a mapping back to the original two-dimensional visibility graph method through the generic visibility graph. Four examples illustrate the application of the proposed visibility graph analysis in complex three-dimensional building and urban environments.

scholarly journals Design and electromagnetic analysis of switched reluctance linear generator in electric vehicle

2021 ◽  
Vol 2108 (1) ◽  
pp. 012016
Author(s):  
Jieyu Liu ◽  
Ye Tang ◽  
Wenyu Cheng ◽  
Changpeng Li
Keyword(s):  
Finite Element ◽  
3D Model ◽  
Structural Characteristics ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Element Analysis ◽  
Switched Reluctance ◽  
Linear Generator ◽  
Simulation Results

Abstract The structural characteristics and basic design requirements of design of switched reluctance linear generator are introduced. According to the general principles and design experience of electromechanical design, the dimension of design of switched reluctance linear generator is determined, and the two-dimensional and three-dimensional static finite element models of design of switched reluctance linear generator are established in Flux 2D and Flux 3D respectively. By comparing the simulation results of the two-dimensional model and the three-dimensional model, it is found that the difference between the real simulation results of the 2D model and the 3D model is small, and the calculation time cost of the 2D finite element simulation is much lower than that of the 3D model. Therefore, the subsequent work of this paper adopts the 2D finite element model. Finally, the static electromagnetic field and electromagnetic characteristics of the design of switched reluctance linear generator are analyzed by finite element analysis.

scholarly journals A two-dimensional depth-averaged -rheology for dense granular avalanches

2015 ◽  
Vol 787 ◽  
pp. 367-395 ◽  
Author(s):  
J. L. Baker ◽  
T. Barker ◽  
J. M. N. T. Gray
Keyword(s):  
Velocity Profile ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Theoretical Models ◽  
Quantitative Agreement ◽  
Surface Velocity ◽  
Momentum Balance ◽  
Test Case ◽  
Two Dimensional ◽  
Uniform Solution

Steady uniform granular chute flows are common in industry and provide an important test case for new theoretical models. This paper introduces depth-integrated viscous terms into the momentum-balance equations by extending the recent depth-averaged ${\it\mu}(I)$-rheology for dense granular flows to two spatial dimensions, using the principle of material frame indifference or objectivity. Scaling the cross-slope coordinate on the width of the channel and the velocity on the one-dimensional steady uniform solution, we show that the steady two-dimensional downslope velocity profile is independent of scale. The only controlling parameters are the channel aspect ratio, the slope inclination angle and the frictional properties of the chute and the sidewalls. Solutions are constructed for both no-slip conditions and for a constant Coulomb friction at the walls. For narrow chutes, a pronounced parabolic-like depth-averaged downstream velocity profile develops. However, for very wide channels, the flow is almost uniform with narrow boundary layers close to the sidewalls. Both of these cases are in direct contrast to conventional inviscid avalanche models, which do not develop a cross-slope profile. Steady-state numerical solutions to the full three-dimensional ${\it\mu}(I)$-rheology are computed using the finite element method. It is shown that these solutions are also independent of scale. For sufficiently shallow channels, the depth-averaged velocity profile computed from the full solution is in excellent agreement with the results of the depth-averaged theory. The full downstream velocity can be reconstructed from the depth-averaged theory by assuming a Bagnold-like velocity profile with depth. For wide chutes, this is very close to the results of the full three-dimensional calculation. For experimental validation, a laser profilometer and balance are used to determine the relationship between the total mass flux in the chute and the flow thickness for a range of slope angles and channel widths, and particle image velocimetry (PIV) is used to record the corresponding surface velocity profiles. The measured values are in good quantitative agreement with reconstructed solutions to the new depth-averaged theory.

Study on Acoustic System Designing of Two Dimensional Ultrasonic Polishing without Abrasives

2010 ◽  
Vol 455 ◽  
pp. 283-287
Author(s):  
Chuan Shao Liu ◽  
Jian Xin Zheng ◽  
Y.F. Liu
Keyword(s):  
Modal Analysis ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Response Analysis ◽  
Two Dimensional ◽  
Acoustic System ◽  
Analysis Method ◽  
Element Analysis ◽  
Harmonic Response Analysis ◽  
Aided Design

Acoustic system is the core component of power ultrasonic, which is designed by traditional analytic method and modal analysis with finite element analysis method. And component of the step-like horn with rectangular sections and tool head used in two dimension ultrasonic polishing without abrasives are studied, and the calculating results and modal analysis results are consistent on the whole. The harmonic response analysis for the component of horn and tool head is carried out and the three dimensional coordinates of the vibrating node on the tool head with maximal displacement are obtained. The fitting result shows that the moving trajectory of such node is ellipses, which meets the experimental requirement well. So a new way for designing acoustic system of two dimensional ultrasonic vibration through combining theoretical calculation with computer aided design may be applied.

Investigation into the Effect of the Nut Thread Run-Out on the Stress Distribution in a Bolt Using the Finite Element Method

2003 ◽  
Vol 125 (3) ◽  
pp. 527-532 ◽  
Author(s):  
J. W. Hobbs ◽  
R. L. Burguete ◽  
E. A. Patterson
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Element Model ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Dimensional Models ◽  
Three Dimensional Models

By means of comparing results from finite element analysis and photoelasticity, the salient characteristics of a finite element model of a nut and bolt have been established. A number of two-dimensional and three-dimensional models were created with varying levels of complexity, and the results were compared with photoelastic results. It was found that both two-dimensional and three-dimensional models could produce accurate results provided the nut thread run-out and friction were modeled accurately. When using two-dimensional models, a number of models representing different positions around the helix of the thread were created to obtain more data for the stress distribution. This approach was found to work well and to be economical.

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