The Study on the Effect of the Lateral Braces on the out-of-Plane Stability of Web Openings Circular Steel Arches

2014 ◽  
Vol 501-504 ◽  
pp. 624-627
Author(s):  
Li Yun Jiang ◽  
Ming Li ◽  
Sen Hao Yang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Large Deformation ◽  
Buckling Load ◽  
Elastic Buckling ◽  
Radial Load ◽  
Buckling Mode ◽  
Web Openings ◽  
Research Results ◽  
Out Of Plane

The paper adopts large deformation elastic buckling finite element method, researches the out-of-plane stability of lateral braced web openings circular steel arches under the distributed radial load and considers the effects of rise-span ratio, arch foot condition, brace rigidity and brace quantity. Research results demonstrate that the out-of-plane buckling load of web openings circular arches increases with the rise of rise-span ratio and increases with the improvement of arch foot constraint. Buckling half waves increase gradually with the increase of lateral brace stiffness. When brace stiffness reaches the brace critical stiffness, the out-of-plane buckling load of steel arches increases will no longer increase with the rise of the brace stiffness, and the buckling mode of steel arches will transit from out-of-plane instability to in-plane instability. The improvement degree of lateral brace to the bucking load of web openings circular steel arches depends on the lateral brace quantity and the size of the brace intervals.

Studies on In-Plane Stability Behavior of Arches with Web Openings

2012 ◽  
Vol 193-194 ◽  
pp. 1296-1299
Author(s):  
Li Yun Jiang ◽  
Man Xiang Liu ◽  
Li Qiang Kang
Keyword(s):  
Finite Element ◽  
Structural Member ◽  
Buckling Load ◽  
Buckling Mode ◽  
Web Openings ◽  
Stability Behavior ◽  
Structural Efficiency ◽  
Finite Element Software ◽  
New Type

As a new type structural member, the steel arch with web openings combines the features of both arches and members with web openings and its applications has been found. Studies on in-plane stability behavior of two-hinged arches with web hexagonal openings are made using Eigen buckling model of the finite element software ANSYS. The buckling load and buckling mode are obtained and the in-plane buckling mode is antisymmetrical. It is shown that buckling load decreases gradually as the circumcircle radius of openings increases and it increases as the gap between openings increases through analysis of buckling load with different parameters such as r/h, g/h, f/l. It can be found that the structural efficiency is the highest when the radius of openings is 0.3h with the aid of optimized function.

A numerical approach based on finite element method for the wrinkling analysis of dielectric elastomer membranes

2021 ◽  
pp. 1-37
Author(s):  
Guoyong Mao ◽  
Wei Hong ◽  
Martin Kaltenbrunner ◽  
Shaoxing Qu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thickness Distribution ◽  
Numerical Approach ◽  
Dielectric Elastomer ◽  
Equivalent Model ◽  
Maxwell Stress ◽  
Buckling Mode ◽  
Post Buckling ◽  
Element Method

Abstract Dielectric elastomer (DE) actuators are deformable capacitors capable of a muscle-like actuation when charged. When subjected to voltage, DE membranes coated with compliant electrodes may form wrinkles due to the Maxwell stress. Here, we develop a numerical approach based on the finite element method (FEM) to predict the morphology of wrinkled DE membranes mounted on a rigid frame. The approach includes two steps, I) pre-buckling and II) post-buckling. In step I, the first buckling mode of the DE membrane is investigated by substituting the Maxwell stress with thermal stress in the built-in function of the FEM platform SIMULIA Abaqus. In step II, we use this first buckling mode as an artificial geometric imperfection to conduct the post-buckling analysis. For this purpose, we develop an equivalent model to simulate the mechanical behavior of DEs. Based on our approach, the thickness distribution and the thinnest site of the wrinkled DE membranes subjected to voltage are investigated. The simulations reveal that the crests/troughs of the wrinkles are the thinnest sites around the center of the membrane and corroborate these findings experimentally. Finally, we successfully predict the wrinkles of DE membranes mounted on an isosceles right triangle frame with various sizes of wrinkles generated simultaneously. These results shed light on the fundamental understanding of wrinkled dielectric elastomers but may also trigger new applications such as programmable wrinkles for optical devices or their prevention in DE actuators.

Steel Sheet Shear Walls with Burring Holes for Low- to Mid-Rise Housings

2019 ◽  
Author(s):  
Yoshimichi Kawai ◽  
Shigeaki Tohnai ◽  
Shinichiro Hashimoto ◽  
Atsushi Sato ◽  
Tetsuro Ono
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Large Deformation ◽  
Deformation Behavior ◽  
Steel Sheet ◽  
Shear Walls ◽  
Shear Load ◽  
Finite Element Analyses ◽  
Plane Shear ◽  
Out Of Plane

<p>Steel sheet shear walls with cold formed edge stiffened burring holes are applied to low- to mid-rise housings in seismically active and typhoon- or hurricane-prone regions. A configuration with burrs on the inside and smooth on the outside enables the construction of omitting the machining of holes for equipments and thinner walls with simplified attachments of finishings. In-plane shear experiments and finite element analyses revealed that the walls allowed shear stress to concentrate in intervals between the burring holes. The walls maintained stable shear load and large deformation behavior, and the deformation areas were limited in the intervals and a large out-of-plane waveform in a sheet was effectively prevented owing to edge stiffened burring ribs. The design methods are developed for evaluating the shear load of the walls at story angle from zero to 1/100, using the idea of decreasing the band width of the inclined tension fields on the intervals with the effects of the thickness.</p>

FEM Simulation of the Effects of Residual Stress on Deformation of Gyroscope Frame

2010 ◽  
Vol 439-440 ◽  
pp. 838-841
Author(s):  
Jun Zhan ◽  
Gui Min Chen ◽  
Xiao Fang Liu ◽  
Qing Jie Liu ◽  
Qian Zhang
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Tensile Stress ◽  
Large Deformation ◽  
Deformation Process ◽  
Fem Simulation ◽  
Machining Process ◽  
The Core

Gyroscope is the core of an inertia system and made by machining process. Machining process imports large residual stress. The residual stress will be released and induces large deformation of gyroscope frame. In this paper, the effects of residual stress on deformation of gyroscope frame were simulated by finite element method. Different stress distribution leads different deformation. Compressive stress can make sample long and tensile stress make sample short. The stress released in deformation process which reduced about 90%.

Influence of Defects on Elastic Buckling Properties of Single-Layered Graphene Sheets

2014 ◽  
Vol 636 ◽  
pp. 11-14 ◽  
Author(s):  
Bao Long Li ◽  
Li Jun Zhou ◽  
Jian Gao Guo
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Vacancy Defect ◽  
Elastic Buckling ◽  
Graphene Sheets ◽  
Effect Factors ◽  
Vacancy Defects ◽  
Size Dependent ◽  
Buckling Stress ◽  
Geometrical Dimensions

Molecular structural mechanics based finite element method has been applied to study the effects of two types of Stone-Wales (SW) defects and vacancy defect on elastic buckling properties of single-layered graphene sheets (SLGSs). The defect effect factors of critical buckling stresses are calculated for the defective SLGSs with different chirality and geometrical dimensions. It is proved that defect effect factors are size-dependent and chirality-dependent. The results show that the vacancy defects will always weaken the SLGSs’ stability, and two types of SW defects have different effects on zigzag and armchair SLGSs. What’s more, the positions of defects also have remarkable influence on the critical buckling stress of SLGSs.

Nonlinear Random Responses of Shell Structures With Spatial Uncertainties

2002 ◽  
Author(s):  
C. W. S. To
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Large Deformation ◽  
Mass Matrix ◽  
Spatial Uncertainty ◽  
Shell Structures ◽  
Time Step ◽  
Central Difference ◽  
Approximation Techniques ◽  
Element Method

A novel procedure for large deformation nonstationary random response computation of shell structures with spatial uncertainty is presented. The procedure is free from the limitations associated with those employing perturbation approximation techniques, such as the so-called stochastic finite element method and probabilistic finite element method, for systems with spatial uncertainties. In addition, the procedure has several important and excellent features. Chief among these are: (a) ability to deal with large deformation problems of finite strain and finite rotation; (b) application of explicit linear and nonlinear element stiffness matrices, mass matrix, and load vectors reduces computation time drastically; (c) application of the averaged deterministic central difference scheme for the updating of co-ordinates and element matrices at every time step makes it extremely efficient compared with those employing the Monte Carlo simulation and the conventional central difference algorithm; and (d) application of the time co-ordinate transformation enables one to study highly stiff structural systems.

scholarly journals Towards 3D Confocal Imaging with Laser-Machined Micro-Scanner

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 1067
Author(s):  
Hilmi Artun Oyman ◽  
Baris Can Efe ◽  
Mustafa Akin Icel ◽  
Yigit Daghan Gokdel ◽  
Onur Ferhanoglu ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stainless Steel ◽  
Laser Cutting ◽  
Laser Doppler Vibrometer ◽  
Confocal Imaging ◽  
Field Of View ◽  
Large Depth ◽  
Out Of Plane ◽  
Plane Mode

A micro-scanner made of stainless-steel is fabricated via laser cutting technology for 3D Lissajous confocal imaging. The multi-gimbaled structure of the device provides two orthogonal torsional modes and three different out-of-plane modes. Torsional modes can be used to achieve 2D scan and all of the out-of-plane modes can be used in changing the focus of the micro-scanner to achieve a 3D scanning pattern. One of the out-of-plane modes along with two orthogonal torsional modes can be employed for scanning a large depth-stack in sparse fashion while another out-of-plane mode can satisfy a much higher scan fill-rate with less field of view (FOV). Simulations of the micro-scanner are obtained using finite element method (FEM) software and compared with the characterization data gathered from Laser Doppler Vibrometer (LDV). Using various out-of-plane modes, the constructed fill patterns are simulated on MATLAB and fill rates compared.

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