scholarly journals Designing of self-deploying origami structures using geometrically misaligned crease patterns

2016 ◽  
Vol 472 (2185) ◽  
pp. 20150235 ◽  
Author(s):  
Kazuya Saito ◽  
Akira Tsukahara ◽  
Yoji Okabe
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Simulations ◽  
Elastic Energy ◽  
Degrees Of Freedom ◽  
New Method ◽  
The Finite Element Method ◽  
Quadrilateral Mesh ◽  
Arbitrary Size ◽  
Folding Simulation

Usually, origami-based morphing structures are designed on the premise of ‘rigid folding’, i.e. the facets and fold lines of origami can be replaced with rigid panels and ideal hinges, respectively. From a structural mechanics viewpoint, some rigid-foldable origami models are overconstrained and have negative degrees of freedom (d.f.). In these cases, the singularity in crease patterns guarantees their rigid foldability. This study presents a new method for designing self-deploying origami using the geometrically misaligned creases. In this method, some facets are replaced by ‘holes’ such that the systems become a 1-d.f. mechanism. These perforated origami models can be folded and unfolded similar to rigid-foldable (without misalignment) models because of their d.f. focusing on the removed facets, the holes will deform according to the motion of the frame of the remaining parts. In the proposed method, these holes are filled with elastic parts and store elastic energy for self-deployment. First, a new extended rigid-folding simulation technique is proposed to estimate the deformation of the holes. Next, the proposed method is applied on arbitrary-size quadrilateral mesh origami. Finally, by using the finite-element method, the authors conduct numerical simulations and confirm the deployment capabilities of the models.

Designing of Self-Deploying Origami Models Using Geometrically Misaligned Crease Patterns

2014 ◽  
Author(s):  
Kazuya Saito ◽  
Akira Tsukahara ◽  
Yoji Okabe
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Simulations ◽  
Elastic Energy ◽  
Degrees Of Freedom ◽  
New Method ◽  
The Finite Element Method ◽  
Quadrilateral Mesh ◽  
Arbitrary Size ◽  
Folding Simulation

Traditionally, origami-based structures are designed on the premise of “rigid folding,” i.e., the facets and fold lines of origami can be replaced with rigid panels and ideal hinges, respectively. Miura-ori and double corrugation surface are representative rigid-foldable origami models. However, from a structural mechanics viewpoint, these systems are usually overconstrained and have negative degrees of freedom (DOF), i.e., the number of constraints exceeds the number of variables. In these cases, the singularity in crease patterns guarantees their rigid foldability. Further, if misalignments are included in the systems’ crease patterns, they become no longer rigid-foldable. This study presents a new method for designing self-deploying origami using the geometrically misaligned creases. In this method, some facets are replaced by “holes” such that the systems become a 1-DOF mechanism. These perforated origami models can be folded and unfolded similar to rigid-foldable (without misalignment) models because of their DOF. Focusing on the removed facets, the holes will deform according to the motion of the frame of the remaining parts. In the proposed method, these holes are filled with elastic parts and store elastic energy for self-deployment. First, a new extended rigid-folding simulation technique is proposed to estimate the deformation of the holes. Next by using the above technique, the proposed method is applied on arbitrary-size quadrilateral mesh origami. Finally, by using the finite-element method, the authors conduct numerical simulations and confirm the deployment capabilities of the models.

scholarly journals Imaging Mueller matrix ellipsometry setup for optical nanoform metrology

2020 ◽  
Vol 238 ◽  
pp. 06006
Author(s):  
Tim Käseberg ◽  
Jana Grundmann ◽  
Johannes Dickmann ◽  
Stefanie Kroker ◽  
Bernd Bodermann
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Simulations ◽  
Mueller Matrix ◽  
The Finite Element Method ◽  
Mueller Matrices ◽  
Microscope Images ◽  
Element Method

We designed, realized, and characterised an imaging Mueller matrix ellipsometry setup for the pixelwise measurement of the Mueller matrices in microscope images. Our setup is capable of performing measurements in reflection as well as in transmission in a broad range of angles of incidence for wavelengths between 400 nm and 700 nm. We compared measurements of specially designed nanostructured samples with AFM and SEM measurements as well as with numerical simulations using the finite element method.

scholarly journals Kane’s Formalism Used to the Vibration Analysis of a Wind Water Pump

Symmetry ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1030
Author(s):  
Gabriel Leonard Mitu ◽  
Eliza Chircan ◽  
Maria Luminita Scutaru ◽  
Sorin Vlase
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Element ◽  
Vibration Analysis ◽  
Degrees Of Freedom ◽  
Transmission Mechanism ◽  
Water Pump ◽  
The Finite Element Method ◽  
Lagrange’S Equation ◽  
Elastic Elements

The paper uses Kane’s formalism to study two degrees of freedom (DOF) mechanisms with elastic elements = employed in a wind water pump. This formalism represents an alternative, in our opinion, that is simpler and more economical to Lagrange’s equation, used mainly by researchers in this type of application. In the problems where the finite element method (FEM) is applied, Kane’s equations were not used at all. The automated computation causes it to be reconsidered in the case of mechanical systems with a high DOF. Analyzing the planar transmission mechanism, these equations were applied for the study of an elastic element. An analysis was then made of the results obtained for this type of water pump. The matrices coefficients of the obtained equations were symmetric or skew-symmetric.

New Deployable Structures Based on an Elastic Origami Model

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Kazuya Saito ◽  
Akira Tsukahara ◽  
Yoji Okabe
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Simple Model ◽  
Elastic Deformation ◽  
Initial Strain ◽  
New Method ◽  
The Finite Element Method ◽  
Deployable Structures ◽  
Elastic Deformations ◽  
Plate Models

Traditionally, origami-based structures are designed on the premise of “rigid folding,” However, every act of folding and unfolding is accompanied by elastic deformations in real structures. This study focuses on these elastic deformations in order to expand origami into a new method of designing morphing structures. The authors start by proposing a simple model for evaluating elastic deformation in nonrigid origami structures. Next, these methods are applied to deployable plate models. Initial strain is introduced into the elastic parts as actuators for deployment. Finally, by using the finite element method (FEM), it is confirmed that the proposed system can accomplish the complete deployment in 3 × 3 Miura-or model.

Simulation on Driving Performance of the Vehicle Based on Modeling Tire

2011 ◽  
Vol 66-68 ◽  
pp. 373-377
Author(s):  
Yue Ying Zhu ◽  
Gui Fan Zhao ◽  
You Shan Wang ◽  
Li Liang Yin
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Simulation ◽  
Driving Performance ◽  
New Method ◽  
The Finite Element Method ◽  
Performance Simulation ◽  
Radial Tire ◽  
Simulation Results ◽  
Dynamics Models

The finite element method was used to establish model of radial tire and analysis the characteristics of tire in driving state to improve the accuracy of simulation on driving performance of off-road vehicle. The dynamics models of the vehicle and its subsystem are designed to provide an off-line dynamic simulation for vehicle driving performance. Simulation and analysis for the vehicle selected previously are made, and the simulation results are compared and analyzed in detail to prove the effectiveness of the new method.

scholarly journals Analysis of Vertical Displacements of the Esperanto Footbridge in Bydgoszcz

2018 ◽  
Vol 28 (2) ◽  
pp. 5-17 ◽  
Author(s):  
Adam Bujarkiewicz ◽  
Jarosław Gajewski ◽  
Tomasz Janiak ◽  
Justyna Sobczak-Piąstka ◽  
Jacek Sztubecki ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Simulations ◽  
The Finite Element Method ◽  
Test Load ◽  
Vertical Displacements ◽  
The Subject ◽  
Theoretical Results ◽  
Element Method

Abstract The subject of the research is a footbridge across the river Brda in Bydgoszcz. The measurements of the footbridge displacements with the test load were undertaken. The paper presents the results of the measurements and compares them with the theoretical results obtained using the finite element method (FEM). On this basis, discrepancy between actual work of the structure and numerical simulations was found. Attempt to explain the reasons for the observed differences and direction of further research were included in the conclusions.

A New Method to Quickly Optimize the Thickness of Multi-Holes Plate

2014 ◽  
Vol 915-916 ◽  
pp. 205-208
Author(s):  
Sheng Bin Wu ◽  
Xiao Bao Liu
Keyword(s):  
Mathematical Model ◽  
Finite Element Method ◽  
Finite Element ◽  
Design Method ◽  
New Method ◽  
The Finite Element Method ◽  
Design Error ◽  
Theory Of Plates ◽  
Plates And Shells ◽  
Element Method

The theory of plates and shells is not adapted to design thickness for the multi-holes plates in engineering. A new method to quickly optimize the thickness based on the finite element method theory was put forward. The method combined the theory of plate with the finite element method to establish a mathematical model and analyzed the influences of load, constraint and complexity on design error. The practices demonstrated that the proposed design method is effective and feasible.

Interference Fit Stress Concentrations with Full Chamfered Hub

2013 ◽  
Vol 572 ◽  
pp. 209-212 ◽  
Author(s):  
Juan Carlos Pérez-Cerdán ◽  
Miguel Lorenzo ◽  
Carmen Blanco
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress State ◽  
Quantitative Determination ◽  
Numerical Simulations ◽  
Not Given ◽  
The Finite Element Method ◽  
Stress Concentrations ◽  
Interference Fit

Quantitative determination of stress concentrations factors (SCF) in interference fits joints is highly relevant since they are not given by the theory of pressure cylinders commonly used for designing them. We study the capability of using a full chamfered hub as a geometrical design for reducing SCF. Stresses distributions and stresses concentrations factors are analyzed as a function of parameters that define the hub geometry with the aim of optimizing the design of proposed modified hubs. To achieve this goal, diverse numerical simulations by means of the finite element method (FEM) were carried out in order to quantitatively estimate the stress state existing at hub-shaft interface.

Unloading of an Elastic-Plastic Loaded Spherical Contact

2004 ◽  
Author(s):  
Yuri Kligerman ◽  
Izhak Etsion ◽  
Yuri Kadin
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Simulations ◽  
The Finite Element Method ◽  
Linear Hardening ◽  
Elastic Plastic ◽  
Contact Loads ◽  
Wide Range ◽  
Residual Curvature ◽  
Loading And Unloading

The process of unloading an elastic-plastic loaded sphere in contact with a rigid flat is studied by the Finite Element Method. The sphere material is assumed isotropic with elastic-linear hardening. The numerical simulations cover a wide range of loading interference deformation of various values of Young’s modulus and Poisson ratios of the sphere material. The contact loads, stresses, and deformations in the sphere during both loading and unloading, are calculated for the range of interferences. Empirical dimensionless expressions are presented for the unloading load-deformation relation, the residual axial displacement and the residual curvature of the sphere after complete unloading.

Experimental-Numerical Approach for Characterization of Mechanical Properties of Thin Electrochemically Deposited Chromium and Copper Films

2010 ◽  
Vol 159 ◽  
pp. 157-162
Author(s):  
Sabina Cherneva ◽  
Milko Yordanov ◽  
Dimitar Stoychev ◽  
Rumen Iankov
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
Numerical Simulations ◽  
Numerical Approach ◽  
Copper Films ◽  
The Finite Element Method ◽  
Electrochemically Deposited ◽  
Nanoindentation Experiment ◽  
Load Displacement

A hybrid experimental-numerical approach, which combines microindentation experiments (where we measure the diagonal of the residual imprint after unloading) and numerical simulations by means of the finite-element method has been developed. The investigated materials in the present work are electrochemically deposited on brass substrates chromium and copper films with known thickness and unknown mechanical properties. Mechanical properties of the brass (CuZn36) substrate are known. Vickers’ microindentation experiments were carried out on the films and as a result the experimental load-displacement curves were obtained. After that the process of microindentation was modelled numerically by means of the finite-element method. Numerically obtained load-displacement curves were compared with the experimental curves. The results show good coincidence between numerical and experimental curves. Additionally it was realized nanoindentation experiment of thin copper film and these two methods (nanoindentation experiment and hybrid experimental-numerical method which combines experiment of microindentation and numerical simulations) for determination of mechanival properties of thin copper films were compared. Results obtained by means of the afore-mentioned two methods almost coincide but the second method is cheaper and gives more information about material properties of the film than the first method. It is shown that the second method is preferable to determine the mechanical properties of thin metal films.

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