Collective Dynamics of Arrays of Micro Cantilevers Interacting Through Fringing Electrostatic Fields

2014 ◽  
Author(s):  
Slava Krylov ◽  
Stella Lulinsky ◽  
Bojan R. Ilic ◽  
Inbar Schneider
Keyword(s):  
Dynamic Properties ◽  
Electrostatic Force ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Silicon On Insulator ◽  
Element Analysis ◽  
Mechanical Coupling ◽  
Electrostatic Fields ◽  
Voltage Dependent ◽  
Electrostatic Coupling

We investigate the collective nonlinear behavior of an array of micro cantilevers interacting by fringing electrostatic fields and fabricated of silicon on insulator (SOI) wafer. The interaction is due to the mechanical coupling originated in the flexibility of the anchor and of the electrostatic coupling through voltage-dependent electrostatic force. In the framework of the reduced order model based on the Galerkin decomposition the array is considered as an assembly of single degree of freedom oscillators. The mechanical coupling matrix is extracted using the full scale finite element analysis of the array while the electrostatic force is approximated by a fit build using the three-dimensional numerical simulation. We show numerically and experimentally that large amplitude collective vibrations of the array can be achieved using parametric excitation while the dynamic properties of the array can be efficiently tuned by the applied voltage.

Nonlinear Finite Element Analysis of Super-Long Pile and Soil Interaction in Soft Soil

2011 ◽  
Vol 201-203 ◽  
pp. 1601-1605 ◽  
Author(s):  
Shang Ping Chen ◽  
Wen Juan Yao ◽  
Sheng Qing Zhu
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Soft Soil ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Element Model ◽  
Element Analysis ◽  
Friction Resistance ◽  
Tip Resistance ◽  
Side Friction

In this paper, a nonlinear three-dimensional finite element model for super-long pile and soil interaction is established. In this model, contact elements are applied to simulate the nonlinear behavior of interaction of super-long pile and soil. A nonlinear elastic constitutive model for concrete is employed to analyze stress-strain relation of pile shaft under the axial load and the Duncan-Chang’s nonlinear constitutive model is used to reflect nonlinear and inelastic properties of soil. The side friction resistance, axial force, pile-tip resistance, and developing trend of soil plastic deformation are obtained and compared with measured results from static load tests. It is demonstrated that a super-long pile has the properties of degradation of side friction resistance and asynchronous action between side and pile-tip resistance, which is different from piles with a short to medium length.

scholarly journals STUDY ON NONLINEAR PAVEMENT RESPONSES OF LOW VOLUME ROADWAYS SUBJECT TO MULTIPLE WHEEL LOADS / NETIESINĖS KELIO DANGOS PRIKLAUSOMYBĖS NUO MAŽO INTENSYVUMO KELIŲ, VEIKIAMŲ DAUGKARTINĖMIS RATŲ APKROVOMIS, TYRIMAS

2011 ◽  
Vol 17 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Minkwan Kim ◽  
Joo Hyoung Lee
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Asphalt Pavement ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Element Model ◽  
Element Analysis ◽  
Nonlinear Stress ◽  
Low Volume ◽  
Stress Dependent

This paper describes numerical analyses on low volume roads (LVRs) using a nonlinear three-dimensional (3D) finite element model (FEM). Various pavement scenarios are analyzed to investigate the effects of pavement layer thicknesses, traffic loads, and material properties on pavement responses, such as surface deflection and subgrade strain. Each scenario incorporates a different combination of wheel/axle configurations and pavement geomaterial properties to analyze the nonlinear behavior of thinly surfaced asphalt pavement. In this numerical study, nonlinear stress-dependent models are employed in the base and subgrade layers to properly characterize pavement geomaterial behavior. Finite element analysis results are then described in terms of the effects of the asphalt pavement thickness, wheel/axle configurations, and geomaterial properties on critical pavement responses. Conclusions are drawn by the comparison of the nonlinear pavement responses in the base and subgrade in association with the effects of multiple wheel/axle load interactions. Santrauka Straipsnyje aprašoma skaitinė mažo intensyvumo kelių analizė, taikant netiesinį—erdvinį baigtinių elementų modelį. Skirtingi dangų paviršiaus variantai analizuojami siekiant ištirti, kokiąįtaką kelio dangos elgsenai, t. y. poslinkiams ir kelio pagrindo deformacijoms, turi dangų sluoksnių storiai, eismo apkrovos ir medžiagų savybės. Kiekvienas kelio dangos variantas turi skirtingas ratų arba ašies ir geometrinių savybių formas, kad būtų galima išanalizuoti netiesinę plonos asfalto dangos paviršiaus elgseną. Šioje skaitinėje analizėje nagrinėjami netiesiniai įtempių modeliai, kurie buvo taikomi pagrindo sluoksniams, siekiant tinkamai apibūdinti geometrinę kelio dangos elgseną. Baigtinių elementų analizės rezultatai toliau nagrinėjami atsižvelgiant į asfalto dangos storį ar ašies formą ir geometrines savybes, priklausomai nuo kritinės kelio dangos būklės. Išvados buvo gautos lyginant netiesines kelių dangos priklausomybes pagrindo sluoksnyje, atsižvelgiant į jų sąveiką su daugkartine ratų apkrova.

Influence of temperature and strain rate on the longitudinal compressive crashworthiness of 3D braided composite tubes and finite element analysis

2016 ◽  
Vol 26 (7) ◽  
pp. 1003-1027 ◽  
Author(s):  
Xianyan Wu ◽  
Qian Zhang ◽  
Bohong Gu ◽  
Baozhong Sun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Rate ◽  
Coupling Effect ◽  
Three Dimensional ◽  
Composite Tubes ◽  
Element Analysis ◽  
Impact Compression ◽  
Mechanical Coupling ◽  
The Impact

This article reports the longitudinal compressive crashworthiness of three-dimensional four-step circular braided carbon/epoxy composite tubes at temperatures of 23, −50, and −100℃ under strain rate ranging from 340 to 760/s both experimentally and finite element analysis. The experimental results showed that the compression strength, stiffness, and specific energy absorption increased with the decrease in temperature and with the increase in strain rate. It also showed that, the compressive damage morphologies were sensitive to the change in temperature and strain rate. A coupled thermal-mechanical numerical analysis was conducted to find the thermo/mechanical coupling effect on the compressive crashworthiness of the three-dimensional composite tube. The temperature distributions in the braided preform and the resin during the impact compression were also calculated through finite element analysis. From the finite element analysis results, the inelastic heat generation was seen to be more in the preform than the matrix and its distribution and accumulation led to the damage progress along the loading direction.

Parametric Excitation of Flexural Vibrations of Micro Beams by Fringing Electrostatic Fields

2010 ◽  
Author(s):  
Slava Krylov ◽  
Nicola Molinazzi ◽  
Tsvi Shmilovich ◽  
Uri Pomerantz ◽  
Stella Lulinsky
Keyword(s):  
Electric Fields ◽  
Parametric Excitation ◽  
Electrostatic Force ◽  
Nonlinear Differential Equations ◽  
Three Dimensional ◽  
Ambient Air ◽  
Silicon On Insulator ◽  
Suggested Approach ◽  
Base Functions ◽  
Fringing Fields

We report on an approach for efficient excitation of large amplitude flexural out-of-plane vibrations of micro beams and present results of theoretical and experimental feasibility study of the suggested principle. An actuating electrode is located symmetrically at the two sides of the beam and is fabricated from the same layer of the wafer. The electrostatic force is engendered by the asymmetry of the fringing fields in the deformed state and acts in the direction opposite to the deflection therefore increasing the effective stiffness of the system. The time-varying voltage applied to the electrode results in the modulation of this electrostatic stiffness and consequently in the parametric excitation of the structure. The device may exhibit large vibrational amplitudes not limited by the pull-in instability common in close-gap actuators. In contrast to previously reported devices excited by the fringing fields, the force considered here is of distributed character. The reduced order model was built using the Galerkin decomposition with linear modes as base functions and the resulting system of nonlinear differential equations was solved numerically. The electrostatic forces were approximated by means of fitting the results of three-dimensional numerical solution for the electric fields. The devices fabricated from a silicon on insulator (SOI) substrate using deep reactive ion etching (DRIE) based process were operated in ambient air conditions and the responses were registered by means of Laser Doppler Vibrometry. The experimental resonant curves were consistent with those predicted by the model. Theoretical and preliminary experimental results illustrated the feasibility of the suggested approach.

scholarly journals Thermo-mechanical coupling–based finite element analysis of the load distribution of planetary roller screw mechanism

2018 ◽  
Vol 10 (6) ◽  
pp. 168781401877525 ◽  
Author(s):  
Shangjun Ma ◽  
Chenhui Zhang ◽  
Tao Zhang ◽  
Geng Liu ◽  
Shumin Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Load Distribution ◽  
Three Dimensional ◽  
Theoretical Models ◽  
Element Model ◽  
Element Analysis ◽  
Mechanical Coupling ◽  
Roller Screw ◽  
Screw Mechanism

In this article, 3D or three-dimensional finite element analysis is used to simulate and evaluate the load distribution characteristics of a planetary roller screw mechanism under thermo-mechanical coupling. The finite element model takes into account the installation modes of the planetary roller screw mechanism, which is verified by comparison with theoretical models for a certain load magnitude in four installation modes. In addition, the effects of the installation mode, load magnitude, and temperature condition on the load distribution are also systematically analyzed. The numerical results reveal a phenomenon of threads separating from the meshing, which indicates that the influence of thermo-mechanical coupling on the load distribution cannot be ignored. Furthermore, the influence of the installation mode on the screw–roller interface is larger than that on the nut–roller interface. Compared with the screw–roller interface, the temperature difference is one of the main conditions affecting the load distribution of the planetary roller screw mechanism and has a significant effect on the nut–roller interface. In addition, the influences of the screw rotational speed and the load magnitude on the load distribution on the screw–roller interface are larger than those on the nut–roller interface for the four installation modes.

Analysis on Aseismic Performance of the Beijing Yintai Center

2010 ◽  
Vol 163-167 ◽  
pp. 3872-3877
Author(s):  
Zhi Qiang Zhang ◽  
Ai Qun Li ◽  
Yong Sun ◽  
Meng Ya Huang
Keyword(s):  
Seismic Behavior ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Response Analysis ◽  
Analysis Method ◽  
Element Analysis ◽  
Plastic Analysis ◽  
Earthquake Action ◽  
Rare Earthquake ◽  
Three Dimensional Finite Element

In this study, the seismic behavior of the main tower building of Beijing Yintai Center is presented with regard to the dynamic characteristics analysis and seismic response analysis. Firstly, by means of three-dimensional finite element analysis software, the dynamic properties and seismic responses under frequent earthquake action of the structure are obtained, respectively. It can be seen that the structure has a rational arrangement for structural elements and has a good seismic behavior. Then, the seismic behavior of the structure is studied through the dynamic elasto-plastic analysis method and static elasto-plastic analysis method under rare earthquake. Analysis results of both analysis methods show that the behavior of the structure accords with the earthquake performance objectives and the structure would not collapse under the rare earthquake action.

Finite Element Analysis of Behavior of Bolted Flange Connections under Bending Loading

2010 ◽  
Vol 26-28 ◽  
pp. 1168-1171
Author(s):  
Bin Wu ◽  
Tao Wang ◽  
Chao Xu ◽  
Bing Xu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Initial Step ◽  
Nonlinear Phenomena ◽  
Sharp Change ◽  
Element Analysis ◽  
Bolted Flange ◽  
Bending Loading

Only a limited number of experimental and analysis reports exist concerning bolted flange connections under bending loading. In order to investigate the complex nonlinear phenomena, three dimensional elasto-plastic finite element analyses are performed. In those analyses, frictional contact model with small sliding option is applied between contacting pair surfaces of all connecting elements. Bolt pretension force is introduced in the initial step of analysis. From this study, the following results are obtainted:1) proposed finite element analysis method can be applicable to estimate complex nonlinear behavior of bolted flange type connections; 2) There is a sharp change in bending stiffness during loading, and lateral slip between two jointed flanges cause the bolt to carry shear load. The design of bolted joints should consider the interaction among cylinders, flanges and bolts.

Environmentally-Assisted Fatigue Analysis Using a Strain-Based Approach

2016 ◽  
Author(s):  
Timothy Gilman ◽  
Francis Ku
Keyword(s):  
High Stress ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Strain Range ◽  
Peak Stress ◽  
Uniaxial Stress ◽  
Pressure Vessels ◽  
Linear Superposition ◽  
Element Analysis ◽  
Plastic Analysis

Traditional design fatigue analyses of pressure vessels and piping equipment have typically used linear-elastic stress analyses, where the stresses caused by various loads, such as thermal, pressure, bending moments, etc. are combined using the principle of linear superposition. Based on high stress locations, geometric and material discontinuities, and other engineering judgements, stress classification lines (SCLs) were defined for where fatigue usage factors would be calculated. It was then necessary to apply simplified elastic-plastic penalty factors, based on the through-wall linearized stresses, to the peak stress amplitudes, in order to account for the nonlinear behavior of materials. Nonlinear finite element analysis that directly calculates strains were not typically used, because of computing and material modeling limitations. However, such analyses, even for complex three-dimensional structures, have become much more practical today with advancements in computing speed and storage capacity. ASME Section III Subarticle NB-3200 includes a provision for performing nonlinear (or “plastic”) analysis (NB-3228.4(c)), but little to no guidance is provided for how to perform the analysis itself. In addition, the procedure for computing the strain range, as currently written in the Code, has been identified as being limited to a uniaxial stress condition and is fundamentally inconsistent with the traditional elastic methodology. This paper provides a proposal for an improved approach for computing fatigue usage and strain rates using nonlinear plastic analysis. Additional guidance for performing these analyses is provided, as they are expected to be used more frequently into the future.

Three Dimensional Finite Element Simulation of Sheet Metal Blanking Process

2014 ◽  
Vol 474 ◽  
pp. 430-435 ◽  
Author(s):  
Łukasz Bohdal ◽  
Leon Kukielka ◽  
Krzysztof Kukielka ◽  
Agnieszka Kułakowska ◽  
Leszek Malag ◽  
...  
Keyword(s):  
Finite Element ◽  
Computational Cost ◽  
Three Dimensional ◽  
Contact Friction ◽  
Main Process ◽  
3D Analysis ◽  
Element Analysis ◽  
Mechanical Coupling ◽  
Blanking Process

The shearing process such as the blanking of sheet metals has been used often to prepare workpieces for subsequent forming operations. The use of FEM simulation is increasing for investigation and optimizing the blanking process. In the current literature a blanking FEM simulations for the limited capability and large computational cost of the three dimensional (3D) analysis has been largely limited to two dimensional (2D) plane axis-symmetry problems. However, a significant progress in modelling which takes into account the influence of real material (e.g. microstructure of the material), physical and technological conditions can be obtained by using 3D numerical analysis methods in this area. The objective of this paper is to present 3D finite element analysis of the ductile fracture, strain distribution and stress in blanking process with the assumption geometrical and physical nonlinearities. The physical, mathematical and computer model of the process are elaborated. Dynamic effects, mechanical coupling, constitutive damage law and contact friction are taken into account. The application in ANSYS/LS-DYNA program is elaborated. The effect of the main process parameter a blanking clearance on the deformation of 1018 steel and quality of the blanks sheared edge is analyzed. The results of computer simulations can be used to forecasting quality of the final parts optimization.

Statistical Analysis of Dynamic Properties of Solid Carbide End Mill

2014 ◽  
Vol 551 ◽  
pp. 37-41
Author(s):  
Yi Kai Yi ◽  
Tie Qiang Gang ◽  
Zhi Qiang Zhang
Keyword(s):  
Statistical Analysis ◽  
High Speed ◽  
Metal Cutting ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Milling Force ◽  
Element Analysis ◽  
Solid Carbide ◽  
Milling Forces ◽  
Force Data

By three-dimensional milling simulations of Aviation Aluminum 7050-T7451 with metal cutting finite element analysis software AdvantEdge FEM, milling force data was obtained and amplitude-frequency characteristics was achieved through Fourier transformation of milling forces. According to mathematical statistical analysis of milling force data, we illustrates that the high-speed milling is a multi-blade interrupted cutting process and the tool vibration is a random vibration. Correlation functions and power spectral density functions of milling force and displacement were calculated in terms of signal processing discipline.

Sign in / Sign up

Export Citation Format

Share Document