The Analysis of Piezoelectric Tube Stack for Radial Vibration Frequency

2014 ◽  
Vol 41 (1-3) ◽  
pp. 20-27
Author(s):  
Zhong Chao ◽  
Wang Likun ◽  
Qin Lei ◽  
Zhou Jingjing ◽  
Chen Cuiying ◽  
...  
Keyword(s):  
Vibration Frequency ◽  
Radial Vibration

Determination of fundamental coupled torsional—radial frequency of single-walled carbon nanotubes

2020 ◽  
pp. 107754632098134
Author(s):  
Sneha Singh
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Shear Modulus ◽  
Vibration Frequency ◽  
Single Walled Carbon Nanotubes ◽  
Radial Vibration ◽  
Single Walled Carbon Nanotube ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes

Research indicates that single-walled carbon nanotubes have a unique coupled torsional–radial vibration as one of their fundamental modes. Determination of their vibration frequency is required for efficient use of single-walled carbon nanotube in nano-electromechanical systems. However, there is no mathematical expression for these frequencies and their dependence on single-walled carbon nanotube geometry is unknown. This article examines the effect of diameter, length, and chirality on the fundamental coupled torsional–radial vibration frequency of single-walled carbon nanotube using molecular–structural–mechanics–approach, finite element analysis, and regression analyses. Consequently, a first-ever mathematical form of this frequency is derived. The form quickly and accurately predicts these frequencies at 1.5% in-sample, and 7.2% out-sample mean absolute percentage error. single-walled carbon nanotubes’ fundamental coupled torsional–radial vibration frequency is found independent of diameter and inversely proportional to length where the proportionality constant depends on chirality. The coupling of modes and the similarity of the frequency form with cylindrical shell suggest that single-walled carbon nanotube behave like thin shells in these vibrations. A form for effective circumferential shear modulus of single-walled carbon nanotube is also derived. This modulus is found to depend only on the chirality where achiral single-walled carbon nanotubes have higher values than chiral single-walled carbon nanotubes. Proposed mathematical forms can be used for characterization of single-walled carbon nanotubes, determination of single-walled carbon nanotubes’ effective shear modulus, and tuning operational frequency of single-walled carbon nanotube-based nano-electromechanical systems.

Influence of Tunnel Blasting on the Close-Spaced Tunnel

2011 ◽  
Vol 243-249 ◽  
pp. 3628-3631
Author(s):  
Yan Ming Ding ◽  
Shu Cui Cong ◽  
Ren Tao Wang ◽  
Hao Wei Li ◽  
Hai Liang Wang
Keyword(s):  
Vibration Frequency ◽  
Vertical Direction ◽  
Tangential Direction ◽  
Vibration Velocity ◽  
Radial Vibration ◽  
Maximum Value ◽  
Tunnel Blasting

According to the blasting monitoring of the main tunnel at hidden digging section of Tuandao Second Road exiting ramp in Kiaochow Bay Cross-harbor Tunnel, the paper shows the influence of vibration on the close-spaced main tunnel. Based on the monitoring results of vibration velocity and vibration frequency in the vertical, horizontal radial and tangential direction, we find that the maximum value of vibration velocity in the main tunnel appears in the range of 5-20m in the rear of the ramp corresponding work face. The magnifying effect of the vibration velocity in the rear of the work face is more obvious than the front in the horizontal radial and tangential direction, and the attenuate effect appears in the front in the vertical direction. The attenuate effect of horizontal radial vibration frequency in the main tunnel appears in the rear of ramp work face. The attenuate effect of vertical frequency in the excavated section is more obvious than the unexcavated.

An estimation algorithm for tire wear using intelligent tire concept

2021 ◽  
pp. 095440702199948
Author(s):  
Bo Li ◽  
Zhenqiang Quan ◽  
Shaoyi Bei ◽  
Lanchun Zhang ◽  
Haijian Mao
Keyword(s):  
Finite Element ◽  
Vibration Frequency ◽  
Hot Spot ◽  
Estimation Algorithm ◽  
Average Error ◽  
Radial Vibration ◽  
Inflation Pressure ◽  
Speed Increase ◽  
Pressure Load ◽  
Tire Wear

Real-time monitoring of tire wear is a hot spot in the research of automobile tires, and it has a great significance to ensure the safety of automobile driving. A tire wear estimation algorithm was proposed based on the relevant knowledge of finite element modal analysis theory and the concept of intelligent tires in this paper. First, the finite element model of the 205/55/R16 radial tire was established through the ABAQUS software, then the finite element method was used to simulate and analyze the influence of tire inflation pressure, load, tire wear, and speed on the tire radial vibration frequency. The simulation results show that inflation pressure and tire wear shows an upward trend with the increase of the vibration frequency of each order in the tire radial direction, and load and speed increase with what increases of tire radial increase frequency. Based on simulation analysis data, combined with the relationship between tire inflation pressure, load, tire wear, speed, and radial vibration frequency, a neural network-based tire wear estimation algorithm is proposed. The estimate results show that the predicted wear curve and the actual wear curve have a higher degree of overlap, the average error is 0.0874 mm, and the average error percentage is 2.78%, Thus, a feasible tire wear estimation algorithm is proposed.

Conceptual design and numerical studies of active flow control aerofoil based on shape-memory alloy and macro fibre composites

2021 ◽  
Vol 125 (1287) ◽  
pp. 830-846
Author(s):  
W. Zhang ◽  
X.T. Nie ◽  
X.Y. Gao ◽  
W.H. Chen
Keyword(s):  
Shape Memory Alloy ◽  
Flow Control ◽  
Shape Memory ◽  
Vibration Frequency ◽  
Active Flow Control ◽  
Flow Characteristics ◽  
Hybrid Design ◽  
Numerical Studies ◽  
Fibre Composites ◽  
Active Flow

ABSTRACTActive flow control for aerofoils has been proven to be an effective way to improve the aerodynamic performance of aircraft. A conceptual hybrid design with surfaces embedded with Shape-Memory Alloy (SMA) and trailing Macro Fibre Composites (MFC) is proposed to implement active flow control for aerofoils. A Computational Fluid Dynamics (CFD) model has been built to explore the feasibility and potential performance of the proposed conceptual hybrid design. Accordingly, numerical analysis is carried out to investigate the unsteady flow characteristics by dynamic morphing rather than using classical static simulations and complicated coupling. The results show that camber growth by SMA action could cause an evident rise of Cl and Cd in the take-off/landing phases when the Angle-of-Attack (AoA) is less than 10°. The transient tail vibration behaviour in the cruise period when using MFC actuators is studied over wide ranges of frequency, AoA and vibration amplitude. The buffet frequency is locked in by the vibration frequency, and a decrease of 1.66–2.32% in Cd can be achieved by using a proper vibration frequency and amplitude.

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