scholarly journals BRB system stability considering frame out-of-plane loading and deformation zone

2021 ◽  
Vol 54 (1) ◽  
pp. 31-39
Author(s):  
Gregory MacRae ◽  
Chin-Long Lee ◽  
Saul Vazquez-Colunga ◽  
Jian Cui ◽  
Saeid Alizadeh ◽  
...  
Keyword(s):  
Deformation Zone ◽  
Steel Frame ◽  
System Stability ◽  
Economical Design ◽  
Force Ratio ◽  
Out Of Plane ◽  
Seismic Displacements ◽  
The Stability ◽  
Brb System ◽  
Plane Deformations

A simple and economical design approach is described for a BRB system, consisting of a BRB within a steel frame, subject to in-plane and out-of-plane seismic displacements. The approach avoids out-of-plane system or brace instability while allowing large frame out-of-plane deformations and desirable BRB axial performance. It also limits the compressive/tension force ratio. It is based on the simple concept that a brace will be stable with two moment-releases (hinges) but that an out-of-plane buckling mechanism may occur with more than two. The hinges are detailed as specified deformation zones (SDZs) at the brace ends. The hinges use a plate which can yield about its weak axis during out-of-plane movement. Simple methods to assess the stability of the brace itself (between hinges) are developed, an example is provided illustrating how the monotonic deformation demand of the simple plate hinge can be assessed, and detailing recommendations are made to restrict the deformation of the boundary elements at the brace ends.

Stability Coefficient of Interlocking Compressed Earth Block Masonry under Axial Compression

2020 ◽  
Author(s):  
Tianya Wang ◽  
Yihong Wang ◽  
Guiyuan Zeng ◽  
Jianxiong Zhang ◽  
Dan Shi
Keyword(s):  
Compressive Strength ◽  
Axial Compression ◽  
Design Guidelines ◽  
Stability Coefficient ◽  
Strength Failure ◽  
Compressed Earth Block ◽  
Out Of Plane ◽  
The Stability ◽  
Earth Block ◽  
Plane Deformations

To investigate the effects of the height-thickness ratio (β) on the mechanical properties and stability coefficients (φs) of interlocking compressed earth block (ICEB) masonry members under axial compression, four groups of specimens with different β of 3.75, 6.75, 11.25, and 14.25 were tested, thereby assessing their stress process, failure mode, compressive strength, and in- and out-of-plane deformations. All the specimens underwent brittle failure under axial compression: the compressive strength was found to decrease in a range from 5.6% to 43% with increasing β, whereas the initial stacking defects and the in- and out-of-plane deformations increased. The specimens became less stable, and we noticed that the overall damage was caused by strength failure and not instability failures. Because the stability coefficient of ICEB-based masonry components cannot be calculated as those of more conventional brickwork, we combined our results with well-established masonry design guidelines and derived an interlocking improvement coefficient.

Atomistic study of the mechanical stability of multi-layered graphene nanobridges

2011 ◽  
Vol 1297 ◽  
Author(s):  
T. Nakajima ◽  
K. Shintani
Keyword(s):  
Mechanical Stability ◽  
Graphene Nanoribbons ◽  
Electronic Devices ◽  
Dynamics Simulation ◽  
Surface Areas ◽  
Out Of Plane ◽  
The Stability ◽  
Atomistic Study ◽  
The Relationship ◽  
Plane Deformations

ABSTRACTThe stability of elongated single- and multi-layered graphene nanoribbons (GNRs) are investigated by molecular-dynamics simulation. In order that GNRs are to be modeled as nanobridges connecting two terminals of electronic devices, the short edges of the GNRs are constrained. The distances between the two constrained edges are gradually increased, and the GNRs are uniaxially strained. The energies and out-of-plane deformations of such uniaxially strained GNRs are examined. The energies of multi-layered GNRs will be lower than those of isolated GNRs because the surface areas of multi-layered GNRs are smaller than the total area of the isolated GNRs. Understanding the relationship between the out-of-plane deformations and strain will lead to the control of the ripple structures of GNRs.

scholarly journals In-Process Measurement of Three-Dimensional Deformations Based on Speckle Photography

2021 ◽  
Vol 11 (11) ◽  
pp. 4981
Author(s):  
Andreas Tausendfreund ◽  
Dirk Stöbener ◽  
Andreas Fischer
Keyword(s):  
Evaluation Method ◽  
Process Analysis ◽  
Plane Deformation ◽  
Three Dimensional ◽  
Machining Process ◽  
Image Correlation ◽  
Speckle Photography ◽  
Process Measurement ◽  
Out Of Plane ◽  
Plane Deformations

In the concept of the process signature, the relationship between a material load and the modification remaining in the workpiece is used to better understand and optimize manufacturing processes. The basic prerequisite for this is to be able to measure the loads occurring during the machining process in the form of mechanical deformations. Speckle photography is suitable for this in-process measurement task and is already used in a variety of ways for in-plane deformation measurements. The shortcoming of this fast and robust measurement technique based on image correlation techniques is that out-of-plane deformations in the direction of the measurement system cannot be detected and increases the measurement error of in-plane deformations. In this paper, we investigate a method that infers local out-of-plane motions of the workpiece surface from the decorrelation of speckle patterns and is thus able to reconstruct three-dimensional deformation fields. The implementation of the evaluation method enables a fast reconstruction of 3D deformation fields, so that the in-process capability remains given. First measurements in a deep rolling process show that dynamic deformations underneath the die can be captured and demonstrate the suitability of the speckle method for manufacturing process analysis.

Stability of Ring-Type MEMS Gyroscopes Subjected to Stochastic Angular Speed Fluctuation

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Samuel F. Asokanthan ◽  
Soroush Arghavan ◽  
Mohamed Bognash
Keyword(s):  
Angular Velocity ◽  
Degrees Of Freedom ◽  
Microelectromechanical Systems ◽  
Damping Ratio ◽  
Operating Conditions ◽  
System Stability ◽  
System Response ◽  
Ring Type ◽  
Mems Gyroscopes ◽  
The Stability

Effect of stochastic fluctuations in angular velocity on the stability of two degrees-of-freedom ring-type microelectromechanical systems (MEMS) gyroscopes is investigated. The governing stochastic differential equations (SDEs) are discretized using the higher-order Milstein scheme in order to numerically predict the system response assuming the fluctuations to be white noise. Simulations via Euler scheme as well as a measure of largest Lyapunov exponents (LLEs) are employed for validation purposes due to lack of similar analytical or experimental data. The response of the gyroscope under different noise fluctuation magnitudes has been computed to ascertain the stability behavior of the system. External noise that affect the gyroscope dynamic behavior typically results from environment factors and the nature of the system operation can be exerted on the system at any frequency range depending on the source. Hence, a parametric study is performed to assess the noise intensity stability threshold for a number of damping ratio values. The stability investigation predicts the form of threshold fluctuation intensity dependence on damping ratio. Under typical gyroscope operating conditions, nominal input angular velocity magnitude and mass mismatch appear to have minimal influence on system stability.

scholarly journals Out-of-plane local mechanism analysis with finite element method

2021 ◽  
Vol 8 (1) ◽  
pp. 130-136
Author(s):  
Roberto Spagnuolo
Keyword(s):  
Finite Element ◽  
Masonry Walls ◽  
Finite Element Models ◽  
Mechanism Analysis ◽  
Fem Method ◽  
Local Mechanism ◽  
Out Of Plane ◽  
Smeared Crack ◽  
The Stability ◽  
No Tension Material

Abstract The stability check of masonry structures is a debated problem in Italy that poses serious problems for its extensive use. Indeed, the danger of out of plane collapse of masonry walls, which is one of the more challenging to evaluate, is traditionally addressed not using finite element models (FEM). The power of FEM is not properly used and some simplified method are preferred. In this paper the use of the thrust surface is suggested. This concept allows to to evaluate the eccentricity of the membrane stresses using the FEM method. For this purpose a sophisticated, layered, finite element with a no-tension material is used. To model a no-tension material we used the smeared crack method as it is not mesh-dependent and it is well known since the early ’80 in an ASCE Report [1]. The described element has been implemented by the author in the program Nòlian by Softing.

Design of Electrostatic Precipitator Power System Based on Auto Disturbance Rejection Controller

2013 ◽  
Vol 846-847 ◽  
pp. 190-194
Author(s):  
Shu Jun Yin ◽  
Xue Ren Li ◽  
Ji Geng Luo
Keyword(s):  
Power Supply ◽  
Disturbance Rejection ◽  
Power Supply System ◽  
Electrostatic Precipitator ◽  
Supply System ◽  
System Stability ◽  
Engineering Practice ◽  
Single Chip ◽  
High Voltage Power Supply ◽  
The Stability

The paper designs a three-phase high voltage power supply system based on active disturbance rejection controller which make single-chip microcomputer ATmega128 as the main control chip and the system improve the stability and control precision of dust removing power. Engineering practice shows that, the DC power supply system has the advantages of convenient operation, high work efficiency, system stability.

scholarly journals Parametric Instability of a Traveling Plate Partially Supported by a Laterally Moving Elastic Foundation

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
V. Kartik ◽  
J. A. Wickert
Keyword(s):  
Data Storage ◽  
Parametric Instability ◽  
Primary Resonance ◽  
Free Edge ◽  
Moving Plate ◽  
Torsional Mode ◽  
Plane Vibration ◽  
Out Of Plane ◽  
Axially Moving ◽  
The Stability

The parametric excitation of an axially moving plate is examined in an application where a partial foundation moves in the plane of the plate and in a direction orthogonal to the plate’s transport. The stability of the plate’s out-of-plane vibration is of interest in a magnetic tape data storage application where the read/write head is substantially narrower than the tape’s width and is repositioned during track-following maneuvers. In this case, the model’s equation of motion has time-dependent coefficients, and vibration is excited both parametrically and by direct forcing. The parametric instability of out-of-plane vibration is analyzed by using the Floquet theory for finite values of the foundation’s range of motion. For a relatively soft foundation, vibration is excited preferentially at the primary resonance of the plate’s fundamental torsional mode. As the foundation’s stiffness increases, multiple primary and combination resonances occur, and they dominate the plate’s stability; small islands, however, do exist within unstable zones of the frequency-amplitude parameter space for which vibration is marginally stable. The plate’s and foundation’s geometry, the foundation’s stiffness, and the excitation’s amplitude and frequency can be selected in order to reduce undesirable vibration that occurs along the plate’s free edge.

On the competition between in-plane and out-of-plane deformations in laser thermal adjustment

2013 ◽  
Vol 45 ◽  
pp. 689-696 ◽  
Author(s):  
Jing Zhou ◽  
Hong Shen ◽  
Xiang Yu ◽  
Jun Hu ◽  
Zhenqiang Yao
Keyword(s):  
Out Of Plane ◽  
Plane Deformations

Retuning the actuator proportional–integral–derivative controller of spinning missiles

2016 ◽  
Vol 231 (14) ◽  
pp. 2594-2602 ◽  
Author(s):  
Wei Zhou ◽  
Shuxing Yang ◽  
Liangyu Zhao
Keyword(s):  
Angular Motion ◽  
Proportional Integral Derivative ◽  
Proportional Integral Derivative Controller ◽  
Proportional Integral ◽  
Out Of Plane ◽  
Integral Element ◽  
The Stability ◽  
Proportional Derivative Controller

The hinge moment acting on the actuator will cause an out-of-plane moment, which is a destabilizing factor to the angular motion of spinning missiles. A new tuning criterion for the actuator controller is proposed to decrease the out-of-plane moment. It is noted that the integral element does not decrease the out-of-plane moment. A carefully designed proportional–derivative controller with some compromises can ensure the stability of the missile and provide good performance for the actuator.

scholarly journals Enhanced asymmetric valley scattering by scalar fields in nonuniform out-of-plane deformations in graphene

2018 ◽  
Vol 98 (16) ◽  
Author(s):  
Ramon Carrillo-Bastos ◽  
Marysol Ochoa ◽  
Saúl A. Zavala ◽  
Francisco Mireles
Keyword(s):  
Scalar Fields ◽  
Out Of Plane ◽  
Plane Deformations
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