LOW FREQUENCY VIBRATIONS OF A THIN CYLINDRICAL SHELL JOINED WITH AN ANNULAR THIN PLATE

2003 ◽  
Vol 27 (3) ◽  
pp. 183-192 ◽  
Author(s):  
Sergei B. Filippov ◽  
Eliza M. Haseganu
Keyword(s):  
Finite Element ◽  
Cylindrical Shell ◽  
Thin Plate ◽  
Low Frequency ◽  
Vibration Modes ◽  
Thin Cylindrical Shell ◽  
Asymptotic Results ◽  
Low Frequencies ◽  
Circular Beam ◽  
Good Agreement

The low frequencies and vibration modes of a thin cylindrical shell joined with an annular thin plate are obtained in this paper by means of asymptotic and numerical methods. If the annulus is wide then the low-frequency vibrations are axisymmetric. For this case a new approximate approach is developed for the evaluation of the low frequencies. If the annulus is narrow, the low-frequency vibrations are non-axisymmetric, the narrow annulus is considered as a circular beam. The equations describing the vibrations of the cylindrical shell stiffened by a circular beam are solved with the help of asymptotic techniques. The asymptotic results are in good agreement with the numerical results obtained by sweep and finite element methods.

Simulation research on low frequency sound absorption of monostable metamaterials

2021 ◽  
Vol 263 (6) ◽  
pp. 648-652
Author(s):  
Tuo Xing ◽  
Xianhui Li ◽  
Xiaoling Gai ◽  
Zenong Cai ◽  
Xiwen Guan
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Theoretical Model ◽  
Finite Element Simulation ◽  
Sound Absorption ◽  
Magnetic Force ◽  
Low Frequency ◽  
Low Frequencies ◽  
Element Simulation ◽  
Simulation Results

The monostable acoustic metamaterial is realized by placing a flexible panel with a magnetic proof mass in a symmetric magnetic field. The theoretical model of monostable metamaterials has been proposed. The method of finite element simulation is used to verify the theoretical model. The magnetic force of the symmetrical magnetic field is simplified as the relationship between force and displacement, acting on the mass. The simulation results show that as the external magnetic force increases, the peak sound absorption shifts to low frequencies. The theoretical and finite element simulation results are in good agreement.

Influence of ossicular chain malformation on the performance of round-window stimulation: A finite element approach

2019 ◽  
Vol 233 (5) ◽  
pp. 584-594 ◽  
Author(s):  
Houguang Liu ◽  
Hu Zhang ◽  
Jianhua Yang ◽  
Xinsheng Huang ◽  
Wen Liu ◽  
...  
Keyword(s):  
Finite Element ◽  
Middle Ear ◽  
Basilar Membrane ◽  
Round Window ◽  
Low Frequency ◽  
Element Model ◽  
Ossicular Chain ◽  
Asymmetric Structure ◽  
Low Frequencies ◽  
Stapes Fixation

As a novel application of implantable middle ear hearing device, round-window stimulation is widely used to treat hearing loss with middle ear disease, such as ossicular chain malformation. To evaluate the influence of ossicular chain malformations on the efficiency of the round-window stimulation, a human ear finite element model, which incorporates cochlear asymmetric structure, was constructed. Five groups of comparison with experimental data confirmed the model’s validity. Based on this model, we investigated the influence of three categories of ossicular chain malformations, that is, incudostapedial disconnection, incus and malleus fixation, and fixation of the stapes. These malformations’ effects were evaluated by comparing the equivalent sound pressures derived from the basilar membrane displacement. Results show that the studied ossicular chain malformations mainly affected the round-window simulation’s performance at low frequencies. In contrast to the fixation of the ossicles, which mainly deteriorates round-window simulation’s low-frequency performance, incudostapedial disconnection increases this performance, especially in the absence of incus process and stapes superstructure. Among the studied ossicular chain malformations, the stapes fixation has a much more severe impact on the round-window stimulation’s efficiency. Thus, the influence of the patients’ ossicular chain malformations should be considered in the design of the round-window stimulation’s actuator. The low-frequency output of the round-window simulation’s actuator should be enhanced, especially for treating the patients with stapes fixation.

Displacement Properties of Newly Developed 3-Dimensional Piezoelectric Actuator at Various AC Frequencies

2007 ◽  
Vol 534-536 ◽  
pp. 1441-1444 ◽  
Author(s):  
Man Soon Yoon ◽  
Y.G. Choi ◽  
Soon Chul Ur
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Piezoelectric Actuator ◽  
Element Model ◽  
Vibration Modes ◽  
Maximum Strain ◽  
Electromechanical Properties ◽  
3 Dimensional ◽  
The Finite Element Model ◽  
Good Agreement

The electromechanical properties of a newly proposed 3-dimensional piezoelectric actuator have been investigated. Especially, the effects of 3-dimensional geometry on the maximum tip displacement were carefully investigated. As a result, it was found that the maximum strain of the 3-dimensional piezoelectric device was significantly enhanced up to 4.5 times higher than that of a disk shape device. This data was in good agreement with the finite element model analysis of strains and vibration modes. Moreover, the field -induced displacement stability of dome-shaped 3- dimensional piezoelectric actuator at various ac freguencies was superior to Rainbow actuator.

Dynamic Analysis of Tapered Plates Based on Higher Order Beam Theory

2014 ◽  
Vol 919-921 ◽  
pp. 79-82
Author(s):  
S.M. Ibrahim ◽  
Y.A. Al-Salloum ◽  
H. Abbas
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Beam Theory ◽  
Longitudinal Axis ◽  
Vibration Modes ◽  
Bending Vibration ◽  
3D Finite Element ◽  
Different Types ◽  
Tapered Plates ◽  
Good Agreement

Modal solutions of plates with uniformly varying cross section using unified beam theory are presented. The results are given in the form of Euler-Bernoulli, Timoshenko and quasi 3D solutions. Numerical results for cantilever and CFCF supported rectangular planform plates are presented. Different types of modes, i.e. axial, bending and torsional modes are observed. The frequency values are in good agreement with 3D finite element results as well as published literature. Due to uniform taper in plate cross section, bending vibration modes become asymmetric along the longitudinal axis of the structure. Further, it can also be noticed that the vibration behavior of thick tapered plates is characterized by the appearance of significant number of axial and torsional modes at lower frequency values.

scholarly journals Finite Element Analysis on Acoustic and Mechanical Performance of Flexible Perforated Honeycomb-Corrugation Hybrid Sandwich Panel

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Jiaming Hu ◽  
Junyi Wang ◽  
Yu Xie ◽  
Chenzhi Shi ◽  
Yun Chen
Keyword(s):  
Finite Element ◽  
Sandwich Panel ◽  
Mechanical Performance ◽  
Mechanical Energy ◽  
Low Frequency ◽  
Rigid Wall ◽  
Acoustic Metamaterials ◽  
Mechanical Stiffness ◽  
Element Analysis ◽  
Low Frequencies

Since proposed, the perforated honeycomb-corrugation sandwich panel has attracted a lot of attention due to its superior broadband sound absorption at low frequencies and excellent mechanical stiffness/strength. However, most existing studies have assumed a structure made of high-strength materials and studied its performance based on the ideal rigid-wall model with little consideration for acoustic-structure interaction, thereby neglecting the structural vibrations caused by the material’s elasticity. In this paper, we developed a more realistic model considering the solid structural dynamics using the finite element method (FEM) and by applying aluminum and rubber as the structural material. The enhancement of the low-frequency performance and inhibition of broadband absorption coexisted in low-strength rubbers, implying a compromise in the selection of Young's modulus to balance these two influences. Further analysis on thermal-viscous dissipation, mechanical energy, and average structural stress indicated that the structure should work right below the resonant frequency for optimization. Based on these findings, we designed a novel aluminum-rubber composite structure possessing enhanced low-frequency absorption, high resistance to shear load, normal compression, and thermal expansion. Our research is expected to shed some light on noise control and the design of multifunctional acoustic metamaterials.

Benchmark Investigation of Welding-Induced Buckling and Its Critical Condition During Thin Plate Butt Welding

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Jiangchao Wang ◽  
Bin Yi
Keyword(s):  
Finite Element ◽  
Thin Plate ◽  
Measurement Data ◽  
Characteristic Parameter ◽  
Welding Distortion ◽  
Butt Welding ◽  
Buckling Behavior ◽  
Out Of Plane ◽  
Inherent Deformation ◽  
Good Agreement

Welding-induced buckling is a special type of welding distortion occurring during thin plate butt welding and was investigated using both experimental and computational approaches for this benchmark investigation. In addition, the characteristic parameter and its magnitude for the occurrence of welding-induced buckling were also presented. Fundamental theories of the inherent deformation, finite strains, and eigenvalues of the structure stiffness matrix were considered to investigate welding-induced buckling. A series of experiments on thin plate butt welding with different heat inputs were conducted, and buckling behavior was observed from the deformed shape and the distribution of out-of-plane welding distortion. Transient nonlinear thermal elastic–plastic finite element (TEP FE) and elastic finite element (FE) analyses were conducted to predict welding-induced buckling, and the results were in good agreement with the measurement data. Criteria for the occurrence of welding-induced buckling were proposed and discussed. Inherent deformation was considered as a characteristic parameter of buckling behavior during welding, and its critical magnitude was calculated using a loading incremental method and eigenvalue analysis with good agreement.

Finite Element Analysis on Vibration Characteristics of a Reciprocating Sliding System

2005 ◽  
Author(s):  
G. X. Chen ◽  
Z. R. Zhou
Keyword(s):  
Finite Element ◽  
Vibration Characteristics ◽  
Vibration Modes ◽  
Vibration Frequencies ◽  
Element Analysis ◽  
Reciprocating Sliding ◽  
Feature Characteristic ◽  
Vibration Coupling ◽  
Friction Induced Vibration ◽  
Good Agreement

In this paper, a finite element method is applied to study the friction-induced vibration characteristics of a reciprocating sliding system. Finite element results are compared with vibration frequencies from an experimental test and are found to have a good agreement. Numerical results show that vibration modes corresponding to test squeals have the feature characteristic of vibration coupling in the normal and friction directions.

Finite Element Analysis of Slab Steel in the Process of Induction Heating

2008 ◽  
Vol 575-578 ◽  
pp. 282-287 ◽  
Author(s):  
R.B. Mei ◽  
Chang Sheng Li ◽  
B. Han ◽  
Xiang Hua Liu
Keyword(s):  
Finite Element ◽  
Induction Heating ◽  
Low Frequency ◽  
Heating Time ◽  
Initial Time ◽  
Heating Process ◽  
Steel Mill ◽  
Element Analysis ◽  
Steel Temperature ◽  
Good Agreement

The induction heating process of slab steel had been discussed by finite element method. The results obtained were in good agreement to the measured value. In addition, the low-frequency induction heating process of slab steel was investigated and analyzed in detail according to the practice requirements of a steel mill. During the heating process of slab steel by low-frequency induction, the temperature increasing speed of surface is faster than that of center in initial time. With the increment of heating time, the temperature increasing speed of surface becomes lower because of the heat loss of boundary. A 90 percent of the slab steel temperature had risen from 1100°C to 1400°C with 110Hz and 6.2×106A/m2 after 30min, which could be satisfied with heating requirements.

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