scholarly journals 3D FEM Analysis of High-Frequency AlN-Based PMUT Arrays on Cavity SOI

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4450 ◽  
Author(s):  
Wenjuan Liu ◽  
Leming He ◽  
Xubo Wang ◽  
Jia Zhou ◽  
Weijiang Xu ◽  
...  
Keyword(s):  
High Frequency ◽  
Electrical Impedance ◽  
Fem Simulation ◽  
Laser Doppler Vibrometer ◽  
Fem Analysis ◽  
3D Models ◽  
Passive Layer ◽  
Mode Shapes ◽  
3D Fem ◽  
Resonant Frequencies

This paper presents three-dimensional (3D) models of high-frequency piezoelectric micromachined ultrasonic transducers (PMUTs) based on the finite element method (FEM). These models are verified with fabricated aluminum nitride (AlN)-based PMUT arrays. The 3D numerical model consists of a sandwiched piezoelectric structure, a silicon passive layer, and a silicon substrate with a cavity. Two types of parameters are simulated with periodic boundary conditions: (1) the resonant frequencies and mode shapes of PMUT, and (2) the electrical impedance and acoustic field of PMUT loaded with air and water. The resonant frequencies and mode shapes of an electrically connected PMUT array are obtained with a laser Doppler vibrometer (LDV). The first resonant frequency difference between 3D FEM simulation and the measurement for a 16-MHz PMUT is reasonably within 6%, which is just one-third of that between the analytical method and the measurement. The electrical impedance of the PMUT array measured in air and water is consistent with the simulation results. The 3D model is suitable for predicting electrical and acoustic performance and, thus, optimizing the structure of high-frequency PMUTs. It also has good potential to analyze the transmission and reception performances of a PMUT array for future compact ultrasonic systems.

FEM Simulation of an Elliptical-Shaped Corrugated Steel Culvert Pipe for Highway Construction

2011 ◽  
Vol 71-78 ◽  
pp. 1613-1616
Author(s):  
Feng Yue ◽  
Xue Jun Wen
Keyword(s):  
Highway Construction ◽  
Fem Simulation ◽  
Fem Analysis ◽  
High Strength ◽  
Cost Effective ◽  
Steel Plates ◽  
3D Fem ◽  
Environment Friendly ◽  
Rapid Construction ◽  
Backfill Soil

In this paper, we discuss the design and calculation methods of elliptical-shaped corrugated steel culvert pipe (ECSCP) used in highway construction. With many advantages such as lightweight, environment friendly, cost-effective, rapid construction, etc., corrugated steel culvert pipe (CSCP) have been widely used in highway construction acting as the alternative of RC culvert in China in recent years. The ECSCP in this paper is a kind of culvert which is fabricated to an elliptical shape with several pieces of corrugated steel plates which are jointed by high strength bolts. This study is conducted on the basis of the ECSCP used in the construction of Shanghai North Outer Ring Line Highway in China. 3D FEM analysis is performed considering several parameters such as modulus of elasticity of the surrounding backfill soil, length of major and minor axis of elliptical-shaped section, eccentricity of vehicles. Some design methods are proposed in this paper, and they will be useful guidelines for safe design of ECSCP.

FEM Analysis for the Influence of Manufacturing Process Defects on Dynamic Behavior of Thin Chromium Microbeam

2014 ◽  
Vol 548-549 ◽  
pp. 958-962 ◽  
Author(s):  
H. Bourouina ◽  
R. Yahiaoui ◽  
B.Y. Majlis ◽  
A. Hassein-Bey ◽  
M.E.A. Benamar ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Behavior ◽  
Manufacturing Process ◽  
Fem Simulation ◽  
Fem Analysis ◽  
Analytical Models ◽  
3D Fem ◽  
Thin Chromium ◽  
Technological Defects

This paper identifies and investigates the influence of technological defects of manufacturing process on the dynamic behavior of thin chromium microbeam. The analytical models will be analyzed and corrected using finite element method (FEM) to determine their validity under influence of technological defects. A semi-analytical model will be proposed for the extraction of corrective factors from 3D FEM simulation of dynamic behavior of microbeam. Final results indicate that the correction of technological defects is very significant for Cr microbeam 80x2x0.95μm3. In other hand, the corrected value of Young’s modulus is very close to the experimental results and it is about 279.1GPa.

3D Modal Analysis of a Loaded Tire with Binary Random Noise Excitation

2019 ◽  
Vol 48 (3) ◽  
pp. 207-223
Author(s):  
Ipar Ferhat ◽  
Rodrigo Sarlo ◽  
Pablo A. Tarazaga
Keyword(s):  
Modal Analysis ◽  
High Frequency ◽  
Random Noise ◽  
Real Life ◽  
Laser Doppler Vibrometer ◽  
Static Condition ◽  
Three Dimensions ◽  
Vibration Measurement ◽  
Mode Shapes ◽  
Testing Techniques

ABSTRACT Modal analysis of tires has been a fundamental part of tire research aimed at capturing the dynamic behavior of a tire. An accurate expression of tire dynamics leads to an improved tire model and a more accurate prediction of tire behavior in real-life operations. Therefore, the main goal of this work is to improve the tire-testing techniques and data range to obtain the best experimental data possible using the current technology. With this goal in mind, we propose novel testing techniques such as piezoelectric excitation, high-frequency bandwidth data, and noncontact vibration measurement. High-frequency data enable us to capture the coupling between the wheel and tire as well as the coupling between airborne and structure-borne noise. Piezoelectric excitation eliminates the dynamic coupling of shakers and the inconsistency of force magnitude and direction of impact hammers as well as added mass effect. Noncontact vibration measurements using three-dimensional (3D) scanning laser Doppler vibrometer (SLDV) are superior to accelerometers because of no mass loading, a high number of measurement points in three dimensions, and high sensitivity. In this work, a modal analysis is carried out for a loaded tire in a static condition. Because of the highly damped nature of tires, multiple input excitation with binary random noise signal is used to increase the signal strength. Mode shapes of the tire are obtained and compared using both accelerometers and SLDV measurements.

scholarly journals The Deformation Analysis of a Deep Frame Top-Down Excavation in Downtown Shanghai Based on the 3D FEM

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Ting Bai ◽  
Dong Xie
Keyword(s):  
Environmental Influence ◽  
Soft Clay ◽  
Fem Simulation ◽  
Fem Analysis ◽  
Deformation Analysis ◽  
Deep Excavation ◽  
Top Down ◽  
3D Fem ◽  
Qualitative Comparison ◽  
Construction Methods

The deformation and environmental influence of the pit excavation in downtown is very important. A 3D FEM analysis is conducted to understand the deformation of a 13.9 to 15.2 m deep excavation with an in-plane dimension of about 189 m width and 251 m length constructed by the frame top-down method (FTDM) in the soft clay region in the Shanghai metropolitan area. The field monitoring results indicate that the magnitudes of wall deflections and ground settlements, along with the column’s uplift difference, are relatively small, which are below the specified protection levels, and that the FTDM is feasible as one of the extralarge excavation construction methods. It is reasonable to predict wall deflection by 3D FEM simulation with qualitative comparison between the simulated column uplifts and the measured data, yet the prediction of the settlement distribution is of no satisfaction. This project studied in this paper not only serves as a special case study calibrated and verified by numerical tools but also provides insights into the design and construction of an extralarge deep excavation using the frame top-down method in soft soils and metropolitan environment.

scholarly journals Resonant Frequency Reduction of Piezoelectric Voltage Energy Harvester by Elastic Boundary Condition

2019 ◽  
Vol 35 (6) ◽  
pp. 779-793 ◽  
Author(s):  
Zhi Chao Ong ◽  
Yu-Hsi Huang ◽  
Sheng-Lun Chou
Keyword(s):  
Resonant Frequency ◽  
Natural Frequency ◽  
Energy Harvester ◽  
Real Life ◽  
Laser Doppler Vibrometer ◽  
Energy Output ◽  
Mode Shapes ◽  
Resonant Frequencies ◽  
Fundamental Natural Frequency ◽  
Piezoelectric Voltage

ABSTRACTMost vibration-based energy harvesters, including piezoelectric harvester system, perform efficiently at only its resonant frequency as linear resonators, usually at very high frequency which are out of the range of frequency of interest. In real life applications, these linear resonators are impractical since real ambient vibrations are simply having varying lower frequencies. Hence, design a tuneable vibration energy harvester at a lower and useful frequency range of interest are essential in allowing promising energy output to meet intended power input at a more practical approach. In this paper, the piezoelectric voltage energy harvester (PVEH) was designed with a flexible fixture with the aim to reduce its first fundamental natural frequency. Two thickness of elastic fixtures were applied to generate power on PVEH. Three experimental techniques were used to measure the vibration characteristics of PVEH. First, the full-field optical technique, amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) measured simultaneously the resonant frequencies and mode shapes. This is followed by the pointwise measurement system, laser Doppler vibrometer (LDV) in which the resonant frequencies were measured by dynamic signal swept-sine analysis. The resonant frequencies and anti-resonant frequencies were also obtained by impedance analysis. The results obtained from experimental measurements were compared with finite element numerical calculation. It is found that the boundary conditions under the elastic fixtures can effectively reduce the resonant frequency of the PVEH with a reasonable voltage output. The fundamental natural frequency of PVEH with the thickness of 0.58-mm elastic fixture is reduced to 37 Hz maintaining at 7.1 volts (1.2 mW), in comparison with the natural frequency on cantilevered PVEH at 78 Hz that produces 7.7 volts (6.5 mW).

Design, 3D FEM Simulation and Prototyping of a Permanent Magnet Spherical Motor

Actuators ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 305
Author(s):  
Umut Yusuf Gündoğar ◽  
Sibel Zorlu Zorlu Partal
Keyword(s):  
Magnetic Flux ◽  
Permanent Magnet ◽  
Tilt Angle ◽  
Degrees Of Freedom ◽  
Experimental Studies ◽  
Fem Simulation ◽  
Fem Analysis ◽  
Magnetic Flux Density ◽  
3D Fem ◽  
Spherical Motor

In recent years, large tilt angles, uniform magnetic flux distributions, strong forces, and large torques for motors have increasingly become important for robotics, biomedical, and automotive applications that have multi-degrees of freedom (MDOFs) motion. Generally, one-degree of-freedom motors are applied in MDOF motion. These situations cause the systems to have very complex and large structures. In order to address these issues, a 2-DOF surface permanent magnet spherical motor with a new mechanical design for the movement of the rotor with a large tilt angle of ±45° was designed, simulated, produced and tested in this paper. The motor consisted of a 4-pole permanent magnet rotor and a 3-block stator with 18 coils. In this study, the mechanical structure of the proposed spherical permanent magnet motor surrounded the rotor with two moving parts to move at a large tilt angle of ±45° without using any mechanical components such as spherical bearings, joint bearings, and bearing covers. Thus, the tilt angle, force, and torque values of the proposed motor have been improved according to MDOF motion motors using spherical bearings, bearing covers, or joint bearings in their mechanical structures in the literature. Ansys Maxwell software was used for the design and simulation of the motor. Three-dimensional (3D) finite element method (FEM) analysis and experimental studies were carried out on the force, torque, and magnetic flux density distribution of the motor. Then, simulation results and experimental results were compared to validate the 3D FEM simulations results.

scholarly journals Experimental Investigations on Dynamic Characteristics of a Multilayer Piezoelectric Stack Actuator

2002 ◽  
Vol 18 (2) ◽  
pp. 95-102 ◽  
Author(s):  
Hsien-Yang Lin ◽  
Chien-Ching Ma
Keyword(s):  
Vibration Mode ◽  
Laser Doppler Vibrometer ◽  
Single Layer ◽  
Mode Shapes ◽  
Electronic Speckle Pattern Interferometry ◽  
Experimental Investigations ◽  
Resonant Frequencies ◽  
Fringe Patterns ◽  
Piezoelectric Disc ◽  
Piezoelectric Stack Actuator

AbstractMultilayer piezoelectric stack actuators are widely used in many industrial applications and the investigation on the dynamic behavior of this element is needed. In this study, two optical interferometric techniques called amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) and laser Doppler vibrometer (LDV) are used to experimentally investigate the vibration characteristics of a single-layer piezoelectric disc and a multilayer piezoelectric stack actuator. These two techniques are full-field measurement for AF-ESPI and point-wise displacement measurement for LDV. Because the clear fringe patterns obtained by the AF-ESPI method will be shown only at resonant frequencies, both the resonant frequencies and corresponding vibration mode shapes of the piezoelectric disc and the multilayer piezoelectric stack actuator are obtained simultaneously by the AF-ESPI method. Interferometric fringe patterns for both the in-plane and out-of-plane vibration mode shapes are demonstrated. In addition to the proposed two optical techniques, numerical computations based on a commercially available finite element package are presented for comparison with the experimental results. Good agreement between the measured data by experimental methods and the numerical results predicted by FEM is found in resonant frequencies and mode shapes for the single-layer piezoelectric disc. However, some discrepancies are observed for the results obtained by AF-ESPI and impedance analysis for the multilayer piezoelectric stack actuator. A detailed discussion is made to address important issues of this problem.

Study on Stiffness and Resonant Frequency of a Parylene Suspended Structure

2004 ◽  
Author(s):  
Seiji Aoyagi ◽  
Dai-ichiro Yoshikawa ◽  
Kenji Makihira ◽  
Yu-Chong Tai
Keyword(s):  
Tensile Stress ◽  
Resonant Frequency ◽  
Mechanical Characteristics ◽  
Fem Simulation ◽  
Laser Doppler Vibrometer ◽  
Thermal Coefficient ◽  
Beam Length ◽  
Resonant Frequencies ◽  
Suspended Structure ◽  
Deposited Film

Parylene has intrinsic tensile stress on account of mismatch of thermal coefficient of expansion (TCE) between the substrate and the deposited film. Therefore, the stiffness k of the Parylene suspended structure under tensile stress is much higher than that under no stress, which also leads to its higher resonant frequency fr. These mechanical characteristics are investigated in this study. First, FEM simulation is employed, and it is proved that k is decreased in proportional to the first power of the beam length l, while it is decreased in proportional to the third power of l under no stress according to the theory of strength of materials. Considering this, a structure with spiral shaped beams is proposed for lowering k. Second, practical Parylene suspended structures are fabricated. The vibrations of them are observed by LDV (Laser Doppler Vibrometer) and their experimental resonant frequencies obtained. They coincide well with simulated ones.

Applications of Holography to Dynamics: High-Frequency Vibrations of Beams

1970 ◽  
Vol 37 (2) ◽  
pp. 287-291 ◽  
Author(s):  
R. Aprahamian ◽  
D. A. Evensen
Keyword(s):  
Cantilever Beam ◽  
Timoshenko Beam ◽  
Holographic Interferometry ◽  
High Frequency ◽  
Beam Theory ◽  
Mode Shapes ◽  
Resonant Frequencies ◽  
Transverse Vibrations ◽  
High Frequency Vibrations ◽  
Time Average

The relatively new experimental technique of holographic interferometry is described, and time-average holography is discussed. Time-average holography has been applied to study high-frequency transverse vibrations of a uniform cantilever beam. Modes from the 5th through the 34th were identified and recorded on holograms, the corresponding resonant frequencies ranged from 500–25,665 cps. In addition, the 77th mode was recorded at 99,395 cps, which demonstrates that the technique is workable at frequencies on the order of 100 kc. The experimental mode shapes and frequencies show good correlation with the Timoshenko beam theory. Other applications of holography to dynamics are briefly discussed.

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