Vibrational Characteristics of Micro Beams

2005 ◽  
Author(s):  
Oladipo Onipede ◽  
Ilya Avdeev ◽  
Amir Khalilollahi ◽  
Lisa Buziewicz
Keyword(s):  
Natural Frequency ◽  
Applied Voltage ◽  
Dynamic Properties ◽  
Electrostatic Force ◽  
Elastic Stiffness ◽  
Critical Parameters ◽  
Driving Voltage ◽  
Mems Devices ◽  
Non Linear ◽  
Voltage Frequency

Several high frequency MEMS devices such as resonators and filters can be modeled as electrostatically driven micro-beams. While their static structural response depends solely on the magnitude of the applied voltage and their elastic stiffness, their dynamic response also depends on their mass, damping properties and the applied voltage frequency. In designing these devices, critical parameters must include the maximum voltage, voltage frequency and the natural frequency of the system. Even though the electrostatic force developed by the voltage is non-linear, the system can be modeled as a harmonic system due to the periodic nature of the response. Results from a non-linear structural-electrostatic dynamic model show the importance of the dynamic properties and the non-linear electrostatic force. The results show significantly lower limiting voltages, especially when the driving voltage is close to the natural frequency of the system. The effect of damping is also addressed.

Scale Effect of Vibration Mode of Micro-Beam in MEMS under Electrostatic-Mechanical Coupling

2010 ◽  
Vol 160-162 ◽  
pp. 1420-1424
Author(s):  
Mei Qin Chen ◽  
Ji Long Su
Keyword(s):  
Natural Frequency ◽  
Scale Effect ◽  
Impact Analysis ◽  
Electromechanical Coupling ◽  
Vibration Mode ◽  
Electrostatic Force ◽  
Mems Devices ◽  
Analysis Model ◽  
Mechanical Coupling ◽  
Micro Cantilever

In order to determine and actively design the vibration characteristics of micro-cantilever in the MEMS devices, it is highly necessary to research on the modal analysis of micro-cantilever which is driven by electrostatic force. This paper analyzes the coupling of mechanical and electrical coupling beam based on the direct coupling method, applies ANSYS software into creating the model of the micro-cantilever to simulation of electromechanical coupling, and establishes the quantitative impact analysis model between natural frequency of vibration and the thickness of a micro-beam with Trans126 transducer element, through directly embedding intrinsic characteristic length of micro-cantilever beam to the scale effect of vibration mode. The main conclusion is that when the thickness of micro-beam is close to the characteristics size of the materials, the natural frequency will show a significant scale effect phenomenon.

scholarly journals Influence of Time Delay on Controlling the Non-Linear Oscillations of a Rotating Blade

Symmetry ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 85
Author(s):  
Yasser Salah Hamed ◽  
Ali Kandil
Keyword(s):  
Time Delay ◽  
Natural Frequency ◽  
Multiple Scales ◽  
Control Process ◽  
Control Force ◽  
Specific Level ◽  
Loop Control ◽  
Positive Displacement ◽  
Non Linear ◽  
Linear Vibrations

Time delay is an obstacle in the way of actively controlling non-linear vibrations. In this paper, a rotating blade’s non-linear oscillations are reduced via a time-delayed non-linear saturation controller (NSC). This controller is excited by a positive displacement signal measured from the sensors on the blade, and its output is the suitable control force applied onto the actuators on the blade driving it to the desired minimum vibratory level. Based on the saturation phenomenon, the blade vibrations can be saturated at a specific level while the rest of the energy is transferred to the controller. This can be done by adjusting the controller natural frequency to be one half of the blade natural frequency. The whole behavior is governed by a system of first-order differential equations gained by the method of multiple scales. Different responses are included to show the influences of time delay on the closed-loop control process. Also, a good agreement can be noticed between the analytical curves and the numerically simulated ones.

scholarly journals Evaluation of the energy consumption of container diesel trucks in a container terminal: A case study at Klaipeda port

2021 ◽  
Vol 104 (3) ◽  
pp. 003685042110355
Author(s):  
Tomas Eglynas ◽  
Sergej Jakovlev ◽  
Valdas Jankunas ◽  
Rimantas Didziokas ◽  
Jolanta Januteniene ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Dynamic Properties ◽  
Container Terminal ◽  
Superposition Principle ◽  
Critical Parameters ◽  
Container Transportation ◽  
Industrial Emissions ◽  
Transportation Process ◽  
Diesel Trucks

Introduction: In the paper, we examine the energy consumption efficiency of specialized container diesel trucks engaged in container transportation at a seaport terminal. Objectives: Using the container terminal at Klaipėda in Lithuania as the background for the research, we produced an improved energy consumption model for measuring the theoretical energy consumption and regeneration of diesel trucks at the terminal and provide a comparative analysis. Methods: We created a mathematical model which describes the instantaneous energy consumption of the diesel trucks, taking into account their dynamic properties and the overall geometry of their routes—“Ship-Truck-Stack-Ship”—using the superposition principle. We investigated other critical parameters relevant to the model and provide a statistical evaluation of the transportation process using data from a case study of Klaipėda port, where we collected measurements of container transportation parameters using georeferenced movement detection and logs from wireless equipment positioned on the diesel-powered container trucks. Results: The modeling results showed that an instantaneous evaluation of energy consumption can reveal areas in the container transportation process which have the highest energy loss and require the introduction of new management and process control initiatives to address the regulations which are designed to decrease harmful industrial emissions and encourage novel technologies and thereby increase the eco-friendliness of existing systems. Conclusion: Based on the research results, the article can provide a reference for the estimation of diesel truck efficiency in seaport terminal operations.

Reduced Order Model of MEMS Sensors Near Natural Frequency

2011 ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Jose C. Solis Silva
Keyword(s):  
Natural Frequency ◽  
Nonlinear Response ◽  
Casimir Effect ◽  
Electrostatic Force ◽  
Reduced Order Model ◽  
Mass Detection ◽  
Order Model ◽  
Reduced Order ◽  
First Order ◽  
Electrostatically Actuated

The nonlinear response of an electrostatically actuated cantilever beam microresonator sensor for mass detection is investigated. The excitation is near the natural frequency. A first order fringe correction of the electrostatic force, viscous damping, and Casimir effect are included in the model. The dynamics of the resonator is investigated using the Reduced Order Model (ROM) method, based on Galerkin procedure. Steady-state motions are found. Numerical results for uniform microresonators with mass deposition and without are reported.

Elastic Stiffness of Volcanic Sand through Resonant Column Tests

2015 ◽  
Vol 775 ◽  
pp. 292-297
Author(s):  
Kostas Senetakis ◽  
Anastasios Anastasiadis
Keyword(s):  
Dynamic Properties ◽  
Experimental Testing ◽  
Elastic Stiffness ◽  
Laboratory Method ◽  
Granular Soils ◽  
Resonant Column ◽  
Torsional Mode ◽  
Resonant Column Test ◽  
Basic Features ◽  
Low Amplitude

The resonant column method is established as a standard laboratory method for the study of the elastic properties of soils. The study presents low-amplitude resonant column test results on volcanic sands with intra-particle voids. The experiments were performed on dry samples prepared at variable relative densities and tested in torsional mode of vibration. In the first part of the article, the important factors that control the elastic stiffness of uncemented sands are described shortly and recent findings on granular soils dynamic properties are presented briefly. The second part describes the basic features of the resonant column used in the investigation and the materials of the study and in the third part representative results of an extensive experimental testing program on volcanic granular soils are presented and discussed with a focus on comparisons between the elastic stiffness of volcanic and quartz granular soils. The importance of the effect of the presence of intra-particle voids within the particle mass of the volcanic soils is emphasized, which in turn affects markedly the global void ratio of the samples.

Dynamic Property Evaluation of a Long-Span Cable-Stayed Bridge (Sutong Bridge) by a Bayesian Method

2018 ◽  
Vol 19 (01) ◽  
pp. 1940010 ◽  
Author(s):  
Yan-Chun Ni ◽  
Qi-Wei Zhang ◽  
Jian-Feng Liu
Keyword(s):  
Natural Frequency ◽  
Dynamic Characteristics ◽  
Structural Damage ◽  
Dynamic Properties ◽  
Modal Identification ◽  
Modal Parameters ◽  
Modal Parameter ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Sutong Bridge

Modal identification aims at identifying the dynamic properties including natural frequency, damping ratio, and mode shape, which is an important step in further structural damage detection, finite element model updating, and condition assessment. This paper presents the work on the investigation of the dynamic characteristics of a long-span cable-stayed bridge-Sutong Bridge by a Bayesian modal identification method. Sutong Bridge is the second longest cable-stayed bridge in the world, situated on the Yangtze River in Jiangsu Province, China, with a total length of 2 088[Formula: see text]m. A short-term nondestructive on-site vibration test was conducted to collect the structural response and determine the actual dynamic characteristics of the bridge before it was opened to traffic. Due to the limited number of sensors, multiple setups were designed to complete the whole measurement. Based on the data collected in the field tests, modal parameters were identified by a fast Bayesian FFT method. The first three modes in both vertical and transverse directions were identified and studied. In order to obtain modal parameter variation with temperature and vibration levels, long-term tests have also been performed in different seasons. The variation of natural frequency and damping ratios with temperature and vibration level were investigated. The future distribution of the modal parameters was also predicted using these data.

Leveraging Flow Regeneration in Individual Energy-Efficient Hydraulic Drives

2021 ◽  
Author(s):  
Damiano Padovani
Keyword(s):  
Natural Frequency ◽  
Dynamic Properties ◽  
Poor Performance ◽  
Control Techniques ◽  
Lower Natural Frequency ◽  
Operating Region ◽  
Depth Analysis ◽  
Study Case ◽  
Boom Crane ◽  
Circuit Configuration

Abstract The current demand for energy efficiency in hydraulics directs towards the replacement of centralized, valve-controlled actuators with individual, throttleless drives. The resulting solutions often require an undesirable sizing of the key components to expand the system’s operating region. Using flow regeneration (i.e., shortcutting the actuator’s chambers) mitigates this issue. Such an option, already stated for individual drives, lacks an in-depth analysis from the control perspective since the dynamic properties are changed (e.g., the natural frequency is decreased to about 60% of the original value). Therefore, this research paper studies a representative single-pump architecture arranged in a closed-circuit configuration. Linear control techniques are used to understand the system dynamics and design a PI-control algorithm that also adds active damping. The outcomes are validated via high-fidelity simulations referring to a single-boom crane as the study case. The results encompassing diverse scenarios indicate that flow regeneration is only interesting in those applications where the dynamic response is not demanding. In fact, the lower natural frequency reduces the system’s bandwidth to about 69% of the original value and affects the closed-loop position tracking drastically. This poor performance becomes evident when medium-to-high actuation velocity is commanded with respect to the maximum value.

Design of Electrostatic Micro Mirrors for Improved Stability Though Surface Contact

1998 ◽  
Author(s):  
Timothy Moulton ◽  
G. K. Ananthasuresh
Keyword(s):  
Design Method ◽  
Electrostatic Force ◽  
Electrostatic Actuation ◽  
Mems Devices ◽  
Complex Dynamic ◽  
Micro Electro Mechanical Systems ◽  
Electrostatically Actuated ◽  
Surface Contact ◽  
Improved Stability ◽  
Mems Process

Abstract There exists a need to stabilize the electrostatic actuation commonly used in Micro-Electro-Mechanical Systems (MEMS). Most electrostatically actuated MEMS devices act as variable capacitors with varying gap between the charged conductors. Electrostatic force in these devices is a nonlinear attractive force between the conductors resulting in a complex dynamic system. These systems are stable for only a small portion of the initial gap. In this paper a design method is presented for electrostatic micro-mirrors with improved stability. Controllable, stable electrostatic actuation can be achieved through surface contact between the two conductors. Once in contact with the surface, the compliance of the structure is used to stabilize the electrostatic actuation over a long range of motion. Beam based variable angle mirrors were designed and fabricated using the Multi-User MEMS Process at MCNC technology center. The design methods for stable electrostatic actuation were tested on these mirrors. Some characteristics are noted and their implementation into future designs is discussed.

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