Quality Factor Optimization Techniques for MEMS Gyroscopes of Frame Structures

2012 ◽  
Vol 590 ◽  
pp. 173-178
Author(s):  
Chao Wei Si ◽  
Guo Wei Han ◽  
Jin Ning ◽  
Wei Wei Zhong ◽  
F.H. Yang
Keyword(s):  
Energy Dissipation ◽  
Quality Factor ◽  
Optimization Techniques ◽  
Frame Structure ◽  
Frame Structures ◽  
Mass Ratio ◽  
Quality Factors ◽  
Quadrature Error ◽  
Factor Ratio ◽  
Mems Gyroscopes

MEMS gyroscopes of frame structures are capable of isolating the quadrature error between the drive motion and the sense motion, which is often utilized in current gyroscope design. But quality factors of previous reported gyroscopes of frame structure are hardly over 1000, which are far more less than that of gyroscopes manufactured before with only one mass block for sensing and driving. Although the effectiveness of isolating quadrature errors is proved, the sensitivity is decreased as well as the power consumption is increased for higher drive voltage. Reasons why MEMS gyroscopes of frame structure has low quality factors is pointed out here with a method of anchor loss mechanism, and the energy dissipation is modeled with a 2 degree of vibration system, which tells the relationship between the mass ratio of the inner mass and the outer frame and the spring factor ratio for supporting masses, and the quality factor assess techniques is proposed here. Therefore the admissible parameters of the mass ratio and the spring factor ratio are given, which makes MEMS gyroscopes of frame structures have advantages of quadrature error isolation as well as high sensitivity. In the end, gyroscopes with optimized parameters and reported parameters are manufactured on SOI wafer, and variations of the quality factors as expected proves the rationality of the proposed energy dissipation model in this paper. For Process limitations, quality factors of gyroscopes of frame structures are improved lower than expected, but far more improved than previous reported gyroscopes, and better results should be realized in more mature and stabilized process.

scholarly journals Influence of the Static Pre-Stress in Micro-Viscothermoelastic Resonators Based on Dual-Phase-Lagging Heat Conduction

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Najat A. Alghamdi ◽  
Hamdy M. Youssef
Keyword(s):  
Heat Conduction ◽  
Energy Dissipation ◽  
Thermal Behavior ◽  
Quality Factor ◽  
Analytical Model ◽  
Relaxation Times ◽  
Mechanical Relaxation ◽  
Length Scale ◽  
Dual Phase ◽  
Quality Factors

Thermal and mechanical relaxation times play vital roles in the values of the quality factor of micro/nanoresonators. They can control the energy dissipation across the coupling of mechanical and thermal behavior. In this paper, we introduce an analytical model that considers a pre-stress in a micro-viscothermoelastic resonator to modify the thermal and mechanical relaxation times and thus higher the quality factor. The impacts of length scale and static pre-stress on the quality factor have been discussed. The model expects that significant improvement in terms of quality factors is possible by tuning the pre-stress and the thermal and mechanical relaxation times parameters, and the isothermal value of frequency have significant effects on the thermal quality factor of the resonators.

scholarly journals Seismic Performance Assessments of RC Frame Structures Strengthened by External Precast Wall Panel

2020 ◽  
Vol 10 (5) ◽  
pp. 1749
Author(s):  
Seung-Ho Choi ◽  
Jin-Ha Hwang ◽  
Sun-Jin Han ◽  
Hyo-Eun Joo ◽  
Hyun-Do Yun ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
Precast Concrete ◽  
Frame Structure ◽  
Frame Structures ◽  
Rc Frame ◽  
Analysis Model ◽  
Energy Dissipation Capacity ◽  
Precast Walls ◽  
Rc Frame Structures

In recent years, a variety of strengthening methods have been developed to improve the seismic performance of reinforced concrete (RC) frame structures with non-seismic details. In this regard, this study proposes a new type of seismic strengthening method that compresses prefabricated precast concrete (PC) walls from the outside of a building. In order to verify the proposed method, a RC frame structure strengthened with precast walls was fabricated, and cyclic loading tests were performed. The results showed that specimens strengthened using the proposed method exhibited further improvements in strength, stiffness and energy dissipation capacity, compared to RC frame structures with non-seismic details. In addition, a nonlinear analysis method, capable of considering the flexural compression and shear behaviors of the walls, was suggested to analytically evaluate the structural behavior of the frame structures strengthened by the proposed method. Using this, an analysis model for frame structures strengthened with precast walls was proposed. Through the proposed model, the analysis and test results were compared in relation to stiffness, strength, and energy dissipation capacity. Then, the failure mode of the column was evaluated based on the pushover analysis. In addition, this study proposed a simplified analysis model that considered the placement of longitudinal reinforcements in shear walls.

Quality Factors of Crystalline Semiconductor Nanocomposite Resonators

2011 ◽  
Author(s):  
Puroorava Chakravarthy ◽  
Gang Li
Keyword(s):  
Molecular Dynamics ◽  
Energy Dissipation ◽  
Quality Factor ◽  
Material Properties ◽  
Quality Factors ◽  
Key Factors ◽  
Nano Scale ◽  
Crystalline Semiconductor ◽  
Bulk Matrix ◽  
Semiconductor Nanocomposite

A nanocomposite can generally be regarded as a solid combining a bulk matrix and nano-scale phases. The phases can be nanoparticles, nanowires, nanoplatelets and etc. The addition of nanosized phases into the bulk matrix can lead to significantly different material properties compared to their macrocomposite counterparts. In this work, we investigate the characteristics of energy dissipation in nanocomposite resonators. By using classical molecular dynamics (MD), we calculate the quality factors of layered and fibrous crystalline semiconductor nanocomposite resonators. Key factors that determine the quality factor of the nanocomposite resonators are identified and analyzed.

Nonlinear Dynamic Analysis of the Damping Frame Structure System

2012 ◽  
Vol 594-597 ◽  
pp. 886-890 ◽  
Author(s):  
Gan Hong ◽  
Mei Li ◽  
Yi Zhen Yang
Keyword(s):  
Energy Dissipation ◽  
Seismic Response ◽  
Nonlinear Dynamic ◽  
Time History ◽  
Time History Analysis ◽  
Frame Structure ◽  
Force Model ◽  
Operating Characteristics ◽  
Restoring Force ◽  
History Analysis

Abstract. In the paper, take full account of energy dissipation operating characteristics. Interlayer shear-frame structure for the analysis of the Wilson-Θmethod ELASTOPLASTIC schedule, the design of a nonlinear dynamic time history analysis procedure. On this basis, taking into account the restoring force characteristics of the energy dissipation system, the inflection point in the restoring force model treatment, to avoid a result of the calculation results of distortion due to the iterative error. A frame structure seismic response time history analysis results show that: the framework of the energy dissipation significantly lower than the seismic response of the common framework, and its role in the earthquake when more significant.

Application of bandlimited anelastic models to wave propagation in highly attenuative media

1995 ◽  
Vol 85 (5) ◽  
pp. 1359-1372
Author(s):  
Hsi-Ping Liu
Keyword(s):  
Wave Propagation ◽  
Quality Factor ◽  
Lower Limit ◽  
Relaxation Function ◽  
Function Approach ◽  
Creep Function ◽  
Frequency Range ◽  
Quality Factors ◽  
Low Frequencies ◽  
Near Surface

Abstract Because of its simple form, a bandlimited, four-parameter anelastic model that yields nearly constant midband Q for low-loss materials is often used for calculating synthetic seismograms. The four parameters used in the literature to characterize anelastic behavior are τ1, τ2, Qm, and MR in the relaxation-function approach (s1 = 1/τ1 and s2 = 1/τ2 are angular frequencies defining the bandwidth, MR is the relaxed modulus, and Qm is approximately the midband quality factor when Qm ≫ 1); or τ1, τ2, Qm, and MR in the creep-function approach (s1 = 1/τ1 and s2 = 1/τ2 are angular frequencies defining the bandwidth, and Qm is approximately the midband quality factor when Qm ≫ 1). In practice, it is often the case that, for a particular medium, the quality factor Q(ω0) and phase velocity c(ω0) at an angular frequency ω0 (s1 < ω0 < s2; s1 < ω0 < s2) are known from field measurements. If values are assigned to τ1 and τ2 (τ2 < τ1), or to τ1 and τ2 (τ2 < τ1), then the two remaining parameters, Qm and MR, or Qm and MR, can be obtained from Q(ω0). However, for highly attenuative media, e.g., Q(ω0) ≦ 5, Q(ω) can become highly skewed and negative at low frequencies (for the relaxation-function approach) or at high frequencies (for the creep-function approach) if this procedure is followed. A negative Q(ω) is unacceptable because it implies an increase in energy for waves propagating in a homogeneous and attenuative medium. This article shows that given (τ1, τ2, ω0) or (τ1, τ2, ω0), a lower limit of Q(ω0) exists for a bandlimited, four-parameter anelastic model. In the relaxation-function approach, the minimum permissible Q(ω0) is given by ln [(1 + ω20τ21)/(1 + ω20τ22)]/{2 arctan [ω0(τ1 − τ2)/(1 + ω20τ1τ2)]}. In the creep-function approach, the minimum permissible Q(ω0) is given by {2 ln (τ1/τ2) − ln [(1 + ω20τ21)/(1 + ω20τ22)]}/{2 arctan [ω0(τ1 − τ2)/(1 + ω20τ1τ2)]}. The more general statement that, for a given set of relaxation mechanisms, a lower limit exists for Q(ω0) is also shown to hold. Because a nearly constant midband Q cannot be achieved for highly attenuative media using a four-parameter anelastic model, a bandlimited, six-parameter anelastic model that yields a nearly constant midband Q for such media is devised; an expression for the minimum permissible Q(ω0) is given. Six-parameter anelastic models with quality factors Q ∼ 5 and Q ∼ 16, constant to 6% over the frequency range 0.5 to 200 Hz, illustrate this result. In conformity with field observations that Q(ω) for near-surface earth materials is approximately constant over a wide frequency range, the bandlimited, six-parameter anelastic models are suitable for modeling wave propagation in highly attenuative media for bandlimited time functions in engineering and exploration seismology.

RESEARCH OF METHODS FOR DECREASE OF THE CAPACITANCE RATIO IN THE STW-RESONATORS

2021 ◽  
pp. 43-56
Author(s):  
S. A. Dobershtein ◽  
N. M. Zhilin ◽  
I. V. Veremeev
Keyword(s):  
Experimental Data ◽  
Quality Factor ◽  
Quality Factors ◽  
Topology Change ◽  
Series Connection ◽  
Capacitance Ratio ◽  
And Topology

This paper presents the research of methods for decrease of the capacitance ratio in the STW-resonators without significant degradation of the quality factor by use of the external inductors and topology change: IDT division on parts and their series connection. The calculated and experimental data are presented for 416 MHz and 766 MHz STW-resonators with quality factors Q = 7000–7978. The capacitance ratio has been reduced from 1200 to 301.

scholarly journals Experimental Study of a New Precast Prestressed Concrete Joint

2018 ◽  
Vol 8 (10) ◽  
pp. 1871 ◽  
Author(s):  
Xueyuan Yan ◽  
Suguo Wang ◽  
Canling Huang ◽  
Ai Qi ◽  
Chao Hong
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
Prestressed Concrete ◽  
Precast Concrete ◽  
Concrete Strength ◽  
Frame Structure ◽  
Loading Test ◽  
Concrete Frame ◽  
Concrete Joints ◽  
Precast Prestressed Concrete

Precast monolithic structures are increasingly applied in construction. Such a structure has a performance somewhere between that of a pure precast structure and that of a cast-in-place structure. A precast concrete frame structure is one of the most common prefabricated structural systems. The post-pouring joint is important for controlling the seismic performance of the entire precast monolithic frame structure. This paper investigated the joints of a precast prestressed concrete frame structure. A reversed cyclic loading test was carried out on two precast prestressed concrete beam–column joints that were fabricated with two different concrete strengths in the keyway area. This testing was also performed on a cast-in-place reinforced concrete joint for comparison. The phenomena such as joint crack development, yielding, and ultimate damage were observed, and the seismic performance of the proposed precast prestressed concrete joint was determined. The results showed that the precast prestressed concrete joint and the cast-in-place joint had a similar failure mode. The stiffness, bearing capacity, ductility, and energy dissipation were comparable. The hysteresis curves were full and showed that the joints had good energy dissipation. The presence of prestressing tendons limited the development of cracks in the precast beams. The concrete strength of the keyway area had little effect on the seismic performance of the precast prestressed concrete joints. The precast prestressed concrete joints had a seismic performance that was comparable to the equivalent monolithic system.

MEMS Microresonators Based on Nanocrystalline Silicon

2004 ◽  
Vol 808 ◽  
Author(s):  
J. Gaspar ◽  
T. Adrega ◽  
V. Chu ◽  
J. P. Conde
Keyword(s):  
Energy Dissipation ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Quality Factors ◽  
Electrostatically Actuated ◽  
Glass Substrates ◽  
Boron Doped ◽  
Resonance Frequencies ◽  
Geometrical Dimensions

ABSTRACTThis paper describes the fabrication and characterization of thin-film nanocrystalline silicon microresonators processed at temperatures below 110°C on glass substrates. The microelectromechanical structures consist of surface micromachined bridges of boron-doped hydrogenated nanocrystalline silicon (p+-nc-Si:H) deposited at 100°C by hot-wire chemical vapor deposition (HWCVD). The microbridges, which are suspended over an Al gate electrode, are electrostatically actuated and the mechanical resonance is detected in vacuum using an optical setup. The resonance frequency and energy dissipation in p+-nc-Si:H based resonators are studied as a function of the geometrical dimensions of the microstructures. Resonance frequencies between 700 kHz and 36 MHz and quality factors as high as 2000 are observed. A Young's modulus of 160 GPa for the structural bridge film is extracted from the experimental data using an electromechanical model and the main intrinsic energy dissipation mechanisms in nc-Si:H microresonators are discussed.

scholarly journals Analysis Of Usability In FIFA 15 and Pro Evolution Soccer (PES) 15 Using Mc Call’s Quality Factors

2016 ◽  
Vol 5 (2) ◽  
pp. 1
Author(s):  
Yudistira Yudistira ◽  
Ahmad Subhan Yazid ◽  
Agung Fatwanto
Keyword(s):  
Quality Factor ◽  
Software Quality ◽  
Usability Testing ◽  
Quality Factors ◽  
User Interest ◽  
And Training ◽  
Better Than

FIFA 15 and Pro Evolution Soccer (PES) 15 are soccer games that are popular in Indonesia. Usability testing needs to be done to assess user interest and satisfaction with both and provide an overview of the comparison of them. The framework used for testing is McCall’S. The test combines operability matrix and training matrix to determine software quality. McCall’S was chosen because it has a reliable and comprehensive quality factor indicators. The results of the tests carried out were data on the operability level of PES15 games of 76.81% ± 15.76% and FIFA15 games of 70.65% ± 20.73%. Testing of training matrices produced 15.96 ± 21.74 seconds for PES15 and 78.29 ± 25.73 seconds for FIFA15 game training matrix. The data shows that reusability of PES15 is better than FIFA15.

Nonlinear Analysis of a RC Frame Structure with Semi-Interlayers Damaged during Wenchuan Earthquake

2010 ◽  
Vol 156-157 ◽  
pp. 467-472
Author(s):  
Peng Tao Yu ◽  
Jing Jiang Sun
Keyword(s):  
Nonlinear Analysis ◽  
Wenchuan Earthquake ◽  
Time History ◽  
Large Earthquake ◽  
Frame Structure ◽  
Nonlinear Time History Analysis ◽  
Frame Structures ◽  
Rc Frame ◽  
Rc Frame Structures ◽  
Nonlinear Time History

Under the excitation of large earthquake, structures enter into high nonlinear stage. Currently, Opensees, Perform-3d and Canny are used as the most popular nonlinear analysis procedures. The fiber model will be introduced firstly and the nonlinear analysis models in Canny are explained in detail. Then Canny2007 is used to conduct nonlinear time history analysis on a heavily damaged frame structure with interlayer in Dujiangyan during Wenchuan Earthquake. Analysis shows that the maximum inter-story drift appears between the interlayer and its upper layer, and the heavy damage agrees well with the results of damage investigation. By comparing the damage extent of frame structures with or without interlayer, it reveals that the seismic performance of RC frame structures without interlayer is obviously better than that of ones with interlayer.

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