Ground Excitation and Resonance in Liquid-Filled Tanks

2006 ◽  
Author(s):  
N. Yang ◽  
G. M. Warner ◽  
H. Nayeb-Hashemi ◽  
M. Olia
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Frequency Analysis ◽  
Natural Frequencies ◽  
Water Levels ◽  
Resonance Phenomenon ◽  
Earthquake Excitation ◽  
Element Analysis ◽  
Cylindrical Tanks ◽  
Natural Frequency Analysis

Recent research has demonstrated that natural frequencies associated with some circumferential modes inn fluid filled tanks may be close to the frequency of earthquake excitation. This can lead to a resonance phenomenon, and consequently failure of the tanks. In this paper, we perform natural frequency analysis of fluid-filled tanks, using finite element analysis. The problem is solved for different geometries and water levels of tanks. Results are provided for circular, cylindrical tanks and cylindrical tanks with coaxial walls and a fluid annulus. Combinations of parameters most likely to cause resonance are presented.

Natural Frequency Analysis of Liquid-Filled Tanks

2005 ◽  
Author(s):  
Rouzbeh Amini ◽  
Grant Warner ◽  
Hamid Nayeb-Hashemi
Keyword(s):  
Natural Frequency ◽  
Frequency Analysis ◽  
Natural Frequencies ◽  
Water Levels ◽  
Resonance Phenomenon ◽  
Modal Shape ◽  
Earthquake Excitation ◽  
Element Analysis ◽  
The Difference ◽  
Natural Frequency Analysis

Traditionally, the cantilever modal shape of liquid-filled tanks has been considered as the most critical mode. However, recent research has demonstrated that natural frequencies associated with some circumferential modes might be close to the frequency of earthquake excitation. This can lead to a resonance phenomenon, and consequently failure of the tanks. In this paper, we perform Natural Frequency Analysis of fluid-filled tanks, using finite element analysis. Modeling and solution employ ADINA potential-based flow elements, which require the assumption of inviscid, irrotational and incompressible flow. The problem is solved for different geometries and water levels of tanks; the results are compared with the current results in the literature and the difference is demonstrated.

Bionic design of the tower for wind turbine

2021 ◽  
pp. 095440622110046
Author(s):  
Yuqiao Zheng ◽  
Fugang Dong ◽  
Huquan Guo ◽  
Bingxi Lu ◽  
Zhengwen He
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Maximum Stress ◽  
Natural Frequencies ◽  
Bionic Design ◽  
Analytic Hierarchy ◽  
Element Analysis ◽  
Maximum Deformation ◽  
Overall Stability ◽  
Biological Selection

The study obtains a methodology for the bionic design of the tower for wind turbines. To verify the rationality of the biological selection, the Analytic Hierarchy Procedure (AHP) is applied to calculate the similarity between the bamboo and the tower. Creatively, a bionic bamboo tower (BBT) is presented, which is equipped with four reinforcement ribs and five flanges. Further, finite element analysis is employed to comparatively investigate the performance of the BBT and the original tower (OT) in the static and dynamic. Through the investigation, it is suggested that the maximum deformation and maximum stress can be reduced by 5.93 and 13.75% of the BBT. Moreover, this approach results in 3% and 1.1% increase respectively in the First two natural frequencies and overall stability.

Natural frequency analysis of a functionally graded rotor-bearing system with a slant crack subjected to thermal gradients

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Arnab Bose ◽  
Prabhakar Sathujoda ◽  
Giacomo Canale
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Power Law ◽  
Beam Theory ◽  
Functionally Graded ◽  
Thermal Gradients ◽  
Element Analysis ◽  
Rotor Bearing ◽  
Natural Frequency Analysis ◽  
Bearing System

Abstract The present work aims to analyze the natural and whirl frequencies of a slant-cracked functionally graded rotor-bearing system using finite element analysis for the flexural vibrations. The functionally graded shaft is modelled using two nodded beam elements formulated using the Timoshenko beam theory. The flexibility matrix of a slant-cracked functionally graded shaft element has been derived using fracture mechanics concepts, which is further used to develop the stiffness matrix of a cracked element. Material properties are temperature and position-dependent and graded in a radial direction following power-law gradation. A Python code has been developed to carry out the complete finite element analysis to determine the Eigenvalues and Eigenvectors of a slant-cracked rotor subjected to different thermal gradients. The analysis investigates and further reveals significant effect of the power-law index and thermal gradients on the local flexibility coefficients of slant-cracked element and whirl natural frequencies of the cracked functionally graded rotor system.

Design and Analysis of a Miniaturization Nanoindentation and Scratch Device

2011 ◽  
Vol 314-316 ◽  
pp. 1792-1795
Author(s):  
Hu Huang ◽  
Hong Wei Zhao ◽  
Jie Yang ◽  
Shun Guang Wan ◽  
Jie Mi ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Amorphous Alloy ◽  
Natural Frequencies ◽  
Geometric Parameters ◽  
Flexure Hinge ◽  
Element Analysis ◽  
Modal Characteristics

In this paper, a miniaturization nanoindentation and scratch device was developed. Finite element analysis was carried out to study static and modal characteristics of x/y flexure hinge and z axis driving hinge as well as effect of geometric parameters on output performances of z axis driving hinge. Results indicated that x/y flexure hinge and z axis driving hinge had enough strength and high natural frequencies. Geometric parameters of z axis driving hinge affected output performances significantly. The model of developed device was established. Indentation experiments of Si and amorphous alloy showed that the developed miniaturization nanoindentation and scratch device worked well and can carry out indentation experiments with certain accuracy.

Finite Element Analysis for the Crankshaft of the Piston Compressor

2010 ◽  
Vol 102-104 ◽  
pp. 17-21
Author(s):  
Bin Zhao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Natural Frequencies ◽  
Piston Compressor ◽  
Element Model ◽  
Ansys Software ◽  
Element Analysis ◽  
Rotating Speed ◽  
Dynamical Characteristics ◽  
The Finite Element Model

In order to study the static and dynamical characteristics of the crankshaft, ANSYS software was used to carry out the corresponding calculations. The entity model of the crankshaft was established by UG software firstly, and then was imported into ANSYS software for meshing, and then the finite element model of the crankshaft was constructed. The crankshaft satisfied the requirement of stiffness and strength through static analysis. The top six natural frequencies and corresponding shapes were acquired through modal analysis, and the every order critical rotating speed of the crankshaft was calculated. The fatigue life of the crank was calculated by fatigue module of ANSYS software finally. These results offered the theoretical guidance for designing, manufacturing and repairing the crankshaft.

Investigation of stiffness of small wind turbine blade based on vibration analysis technique

2019 ◽  
Vol 44 (1) ◽  
pp. 49-59
Author(s):  
Nilesh Chandgude ◽  
Nitin Gadhave ◽  
Ganesh Taware ◽  
Nitin Patil
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Wind Turbine ◽  
Natural Frequency ◽  
Vibration Analysis ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Element Analysis ◽  
Finite Element Software ◽  
Small Wind Turbine

In this article, three small wind turbine blades of different materials were manufactured. Finite element analysis was carried out using finite element software ANSYS 14.5 on modeled blades of National Advisory Committee for Aeronautics 4412 airfoil profile. From finite element analysis, first, two flap-wise natural frequencies and mode shapes of three different blades are obtained. Experimental vibration analysis of manufactured blades was carried out using fast Fourier transform analyzer to find the first two flap-wise natural frequencies. Finally, the results obtained from the finite element analysis and experimental test of three blades are compared. Based on vibration analysis, we found that the natural frequency of glass fiber reinforced plastic blade reinforced with aluminum sheet metal (small) strips increases compared with the remaining blades. An increase in the natural frequency indicates an increase in the stiffness of blade.

Free Vibration Analysis of PZT Glide Heads

1999 ◽  
Vol 121 (4) ◽  
pp. 984-988 ◽  
Author(s):  
Alex Y. Tsay ◽  
Jin-Hui Ouyang ◽  
C.-P. Roger Ku ◽  
I. Y. Shen ◽  
David Kuo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Natural Frequencies ◽  
Laser Doppler Vibrometer ◽  
Free Vibration Analysis ◽  
Mode Shapes ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Bonding Length ◽  
Measured Displacement

This paper studies natural frequencies and mode shapes of a glide head with a piezoelectric transducer (PZT) through calibrated experiments and a finite element analysis. In the experiments, the PZT transducer served as an actuator exciting the glide head from 100 kHz to 1.3 MHz, and a laser Doppler vibrometer (LDV) measured displacement of the glide head at the inner or outer rail. The natural frequencies were measured through PZT impedance and frequency response functions from PZT to LDV. In the finite element analysis, the glide head was meshed by brick elements. The finite element results show that there are two types of vibration modes: slider modes and PZT modes. Only the slider modes are important to glide head applications. Moreover, natural frequencies predicted from the finite element analysis agree well with the experimental results within 5% of error. Finally, the finite element analysis identifies four critical slider dimensions whose tolerance will significantly vary the natural frequencies: PZT bonding length, wing thickness, slider thickness, and air bearing recess depth.

Effect of Osteoporosis on Natural Frequencies in Mouse Femur: Vibration Test and Micro-CT Based Finite Element Analysis

2006 ◽  
Vol 326-328 ◽  
pp. 851-854 ◽  
Author(s):  
Yoon Hyuk Kim ◽  
Chang Hwan Byun ◽  
Taek Yul Oh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mesh Generation ◽  
Natural Frequencies ◽  
Treated Group ◽  
Vibration Test ◽  
Micro Ct ◽  
Element Analysis ◽  
Generation Algorithm ◽  
The Finite Element Analysis

In this study, the change of the natural frequencies in mouse femurs with osteoporosis was investigated based on a vibration test and a finite element. Three groups of the femurs include the osteoporotic group, the treated group and the normal group. In the vibration test, the natural frequencies were measured by the mobility test. For the finite element analysis, the micro finite element model of the femur was reconstructed using the Micro-CT images and the Voxel mesh generation algorithm. From the results, the averaged natural frequencies in the osteoporotic group were the highest, followed by those in the treated group. The finite element models were validated within 15% errors by comparing the natural frequencies in the finite element analysis with those in the vibration test. The developed Micro-CT system, the Voxel mesh generation algorithm, the presented finite element analysis, and vibration test could be useful for the investigation of the structural change of the bone tissue, and the diagnosis and the treatment in the osteoporosis.

Forced Vibration Behavior of Adhesively Bonded Single-Lap Joint

2011 ◽  
Vol 110-116 ◽  
pp. 3611-3616 ◽  
Author(s):  
Xiao Cong He
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Forced Vibration ◽  
Natural Frequencies ◽  
Dynamic Test ◽  
Lap Joint ◽  
Adhesively Bonded ◽  
Element Analysis ◽  
Single Lap Joint ◽  
Vibration Behavior

This paper deals with forced vibration behavior of adhesively bonded single-lap joint theoretically and experimentally. The finite element analysis (FEA) software was used to predict the natural frequencies and frequency response functions (FRFs) of the joint. The dynamic test software and the data acquisition hardware were used in experimental measurement of the dynamic response of the joint. It is shown that the natural frequencies of the joint from experiment are lower than those predicted using finite element analysis. It is also found that the measued FRFs are close to the predicted FRFs for the first two modes of vibration of the joint. Above the second mode of vibration, there is considerable discrepancy between the measured and predicted FRFs.

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