scholarly journals Design and Mechanical Sensitivity Analysis of a MEMS Tuning Fork Gyroscope with an Anchored Leverage Mechanism

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3455 ◽  
Author(s):  
Li ◽  
Gao ◽  
Jin ◽  
Liu ◽  
Guan ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Analytical Solutions ◽  
Tuning Fork ◽  
Fem Simulation ◽  
Micro Electro Mechanical System ◽  
Stiffness Ratio ◽  
Sense Mode ◽  
Mechanical Sensitivity ◽  
Improvement Rate ◽  
Theoretical Results

This paper presents the design and analysis of a new micro-electro-mechanical system (MEMS) tuning fork gyroscope (TFG), which can effectively improve the mechanical sensitivity of the gyroscope sense-mode by the designed leverage mechanism. A micromachined TFG with an anchored leverage mechanism is designed. The dynamics and mechanical sensitivity of the design are theoretically analyzed. The improvement rate of mechanical sensitivity (IRMS) is introduced to represent the optimization effect of the new structure compared with the conventional one. The analytical solutions illustrate that the IRMS monotonically increases with increased stiffness ratio of the power arm (SRPA) but decreases with increased stiffness ratio of the resistance arm (SRRA). Therefore, three types of gyro structures with different stiffness ratios are designed. The mechanical sensitivities increased by 79.10%, 81.33% and 68.06% by theoretical calculation. Additionally, FEM simulation demonstrates that the mechanical sensitivity of the design is in accord with theoretical results. The linearity of design is analyzed, too. Consequently, the proposed new anchored leverage mechanism TFG offers a higher displacement output of sense mode to improve the mechanical sensitivity.

scholarly journals Metamaterials with engineered failure load and stiffness

2019 ◽  
Vol 116 (48) ◽  
pp. 23960-23965 ◽  
Author(s):  
Sai Sharan Injeti ◽  
Chiara Daraio ◽  
Kaushik Bhattacharya
Keyword(s):  
Mechanical Properties ◽  
Sensitivity Analysis ◽  
Critical Load ◽  
Failure Load ◽  
Weight Ratio ◽  
Fracture Load ◽  
Specific Load ◽  
Load To Failure ◽  
Failure Location ◽  
Theoretical Results

Architected materials or metamaterials have proved to be a very effective way of making materials with unusual mechanical properties. For example, by designing the mesoscale geometry of architected materials, it is possible to obtain extremely high stiffness-to-weight ratio or unusual Poisson’s ratio. However, much of this work has focused on designing properties like stiffness and density, and much remains unknown about the critical load to failure. This is the focus of the current work. We show that the addition of local internal prestress in selected regions of architected materials enables the design of materials where the critical load to failure can be optimized independently from the density and/or quasistatic stiffness. We propose a method to optimize the specific load to failure and specific stiffness using sensitivity analysis and derive the maximum bounds on the attainable properties. We demonstrate the method in a 2D triangular lattice and a 3D octahedral truss, showing excellent agreement between experimental and theoretical results. The method can be used to design materials with predetermined fracture load, failure location, and fracture paths.

Seismic reflectivity of hydraulic fractures approximated by thin fluid layers

Geophysics ◽  
2013 ◽  
Vol 78 (4) ◽  
pp. T79-T87 ◽  
Author(s):  
A. Oelke ◽  
D. Alexandrov ◽  
I. Abakumov ◽  
S. Glubokovskikh ◽  
R. Shigapov ◽  
...  
Keyword(s):  
Analytical Solutions ◽  
Fluid Layer ◽  
Synthetic Data ◽  
P Wave ◽  
Hydraulic Fractures ◽  
Reflection Coefficients ◽  
S Wave ◽  
Reservoir Properties ◽  
Thin Fluid ◽  
Theoretical Results

We have analyzed the angle-dependent reflectivity of microseismic wavefields at a hydraulic fracture, which we modeled as an ideal thin fluid layer embedded in an elastic, isotropic solid rock. We derived full analytical solutions for the reflections of an incident P-wave, the P-P and P-S reflection coefficients, as well as for an incident S-wave, and the S-S and S-P reflection coefficients. The rather complex analytical solutions were then approximated and we found that these zero-thickness limit approximations are in good agreement with the linear slip model, representing a fracture at slip contact. We compared the analytical solutions for the P-P reflections with synthetic data that were derived using finite-difference modeling and found that the modeling confirmed our theoretical results. For typical parameters of microseismic monitoring by hydraulic fracturing, e.g., a layer thickness of [Formula: see text] and frequencies of [Formula: see text], the reflection coefficients depend on the Poisson’s ratio. Furthermore, the reflection coefficients of an incident S-wave are remarkably high. Theoretical results suggested that it is feasible to image hydraulic fractures using microseismic events as a source and to solve the inverse problem, that is, to interpret reflection coefficients extracted from microseismic data in terms of reservoir properties.

scholarly journals Sensitivity Analysis of the Matrix Equation from Interpolation Problems

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Jing Li ◽  
Yuhai Zhang
Keyword(s):  
Sensitivity Analysis ◽  
Approximate Solution ◽  
Matrix Equation ◽  
Nonlinear Matrix Equation ◽  
Backward Error ◽  
Perturbation Bound ◽  
Interpolation Problems ◽  
The Matrix ◽  
Nonlinear Matrix ◽  
Theoretical Results

This paper studies the sensitivity analysis of a nonlinear matrix equation connected to interpolation problems. The backward error estimates of an approximate solution to the equation are derived. A residual bound of an approximate solution to the equation is obtained. A perturbation bound for the unique solution to the equation is evaluated. This perturbation bound is independent of the exact solution of this equation. The theoretical results are illustrated by numerical examples.

A Multiple-Beam Tuning-Fork Gyroscope With High Quality Factors

2009 ◽  
Author(s):  
Ren Wang ◽  
Shiva Krishna Durgam ◽  
Zhili Hao ◽  
Linda Vahala
Keyword(s):  
Tuning Fork ◽  
Rate Sensitivity ◽  
Sense Mode ◽  
Quality Factors ◽  
Drive Mode ◽  
High Quality ◽  
Multiple Beam ◽  
Frequency Split ◽  
Operation Frequency ◽  
Mask Fabrication

This paper reports on the design, fabrication, and testing of a multiple-beam tuning-fork gyroscope featuring high Quality factors (Q). A multiple-beam tuning-fork structure is designed to achieve high Qs in its drive mode and sense mode. The gyroscope is fabricated on a 30μm-thick SOI wafer using a one-mask fabrication process. The measured Qs of the fabricated gyroscope are 162,060 in the drive-mode and 85,168 in the sense mode at an operation frequency of 16.8kHz. Under a frequency split of 6Hz, the prototype device demonstrates a rate sensitivity of 0.02mV/°/sec.

Design and Fabrication of Quartz Micro-Electro-Mechanical System-Based Double-Ended Tuning Fork with Variable Sections

2011 ◽  
Vol 50 (6) ◽  
pp. 06GM06
Author(s):  
Jinxing Liang ◽  
Xuefeng Li ◽  
Hongsheng Li ◽  
Yunfang Ni ◽  
Kunyu Li ◽  
...  
Keyword(s):  
Mechanical System ◽  
Tuning Fork ◽  
Micro Electro Mechanical System

scholarly journals On Bandwidth Characteristics of Tuning Fork Micro-Gyroscope with Mechanically Coupled Sense Mode

Sensors ◽  
2014 ◽  
Vol 14 (7) ◽  
pp. 13024-13045 ◽  
Author(s):  
Yunfang Ni ◽  
Hongsheng Li ◽  
Libin Huang ◽  
Xukai Ding ◽  
Haipeng Wang
Keyword(s):  
Tuning Fork ◽  
Sense Mode

A Theory of Lubrication by Microirregularities

1966 ◽  
Vol 88 (1) ◽  
pp. 177-185 ◽  
Author(s):  
D. B. Hamilton ◽  
J. A. Walowit ◽  
C. M. Allen
Keyword(s):  
Closed Form ◽  
Analytical Solutions ◽  
Load Capacity ◽  
Face Seal ◽  
Lubrication Mechanism ◽  
Surface Asperity ◽  
Parallel Surfaces ◽  
Theoretical Results

This paper describes a theory of liquid lubrication applicable to parallel surfaces, such as the surfaces of a rotary-shaft face seal. The lubrication mechanism presented is based on surface microirregularities and associated film cavities. Closed-form analytical solutions are obtained giving load capacity as a function of speed, viscosity, and surface-asperity dimensions. The theoretical results agree qualitatively with load capacity determined experimentally for three asperity distributions.

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