Vibration Localization in Plates With Misplaced Intermediate Supports in Two Orthogonal Directions

2003 ◽  
Author(s):  
Wei-Chau Xie ◽  
Zhihua Chen
Keyword(s):  
Forced Vibration ◽  
Natural Frequencies ◽  
Current Approach ◽  
Vibration Response ◽  
Vibration Modes ◽  
The Finite Element Method ◽  
Concentrated Load ◽  
Vibration Localization ◽  
Vibration Responses ◽  
Simple Supports

This paper investigates the effect of small misplacements on both the free vibration modes and forced vibration responses of a four-panel simply supported plate with two intermediate simple supports in two orthogonal directions. Kantorovich’s method is employed to obtain the natural frequencies and the corresponding vibration modes. Galerkin’s method is applied to determine the forced vibration response of the four-panel plate subjected to a harmonic concentrated load at the center of one of its four panels. Comparisons between numerical results obtained using the current approach and those using the exact solution and the finite element method are made to demonstrate the accuracy of the current approach. It is found that the small misplacements of the intermediate supports have dramatic effects on the vibration response of the plate. The larger the misplacement of the intermediate supports, the larger the degree of vibration localization. By judiciously introducing misplacements in the intermediate simple supports, the vibration of some of the four panels may be controlled.

scholarly journals Influence of the flexibility of beams and slabs in static response and dynamic properties

2016 ◽  
Vol 9 (6) ◽  
pp. 842-855 ◽  
Author(s):  
J. R. BUENO ◽  
◽  
D. D. LORIGGIO ◽  
Keyword(s):  
Finite Element Method ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Vibration Modes ◽  
Linear Regime ◽  
Static Response ◽  
The Finite Element Method ◽  
Standard Code ◽  
The Relationship ◽  
Brazilian Standard

Abstract This article examines numerically the flexibility influence of support beams in static response and dynamic properties of a symmetric plate formed by massive slabs of reinforced concrete in elastic linear regime, using the Finite Element Method. In the static response the variation of bending mo-ments and displacements are evaluated, which depend on the relationship between the flexibility of the slab and the beam. The evaluation of dynamic properties is held in undamped free vibration, through which the vibration modes and the values of the natural frequencies is obtained, which are compared with the limits of the Brazilian standard code for design of concrete structures. Results show that the response may show great variation due to the change in the relationship between bending stiffness of the slabs and the beams.

Analysis of the Leakage-Flow-Induced Vibration of a Slip Joint in a Jet Pump of a Boiling Water Reactor

2019 ◽  
Vol 390 ◽  
pp. 23-31 ◽  
Author(s):  
J. Cruz Castro ◽  
E. Hernández Palafox ◽  
I.A. Alarcón Sánchez ◽  
Luis H. Hernández-Gómez ◽  
Pablo Ruiz-López ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Natural Frequencies ◽  
Excitation Frequency ◽  
Vibration Modes ◽  
The Finite Element Method ◽  
Jet Pump ◽  
Flow Induced Vibration ◽  
Ansys Fluent ◽  
Pump Assembly ◽  
Fourth Mode

The purpose of this analysis is to evaluate the structural integrity of the jet pump assembly of a BWR during the performance of its operational and safety functions. The natural frequencies and vibration modes of the jet pump assembly immersed in water were determined. It was observed that the fourth mode shape was torsional, and its associated resonance frequency was 41.82 Hz. Also, the vibration induced by the flow in the leakage of the slip joint was analyzed with an axisymmetric model. The gap of the slip joint was varied from 0.2 mm until 0.65bmm. A gap between 0.6 and 0.64, would cause flow-induced vibration because this excitation frequency matches with the fourth natural frequency of the jet pump assembly. The above was carried out using computational fluid dynamics, as well as the finite element method, with ANSYS Structural and ANSYS Fluent codes.

Coupling of Turbomachine Blade Vibrations Through the Rotor

1967 ◽  
Vol 89 (4) ◽  
pp. 502-512 ◽  
Author(s):  
J. T. Wagner
Keyword(s):  
Forced Vibration ◽  
Natural Frequencies ◽  
Vibration Response ◽  
Analytical Models ◽  
Finite Mass ◽  
Blade Vibration ◽  
Resonant Frequencies ◽  
Vibration Tests ◽  
Flexible Disk ◽  
Turbomachine Blade

The forced vibration response of subsystems with different natural frequencies and damping, attached to a foundation with finite stiffness or mass, is calculated. Analytical models include simulations of turbomachine blading on a flexible disk or on a rotor with finite mass. Coupling through the disk or rotor explains variations in resonant frequencies and amplitudes that have been observed in blade-vibration tests. Effects on damping measurements are also determined.

scholarly journals Nonlinear forced vibration response of smart two-phase nano-composite beams to external harmonic excitations

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Soraya Mareishi ◽  
Hamed Kalhori ◽  
Mohammad Rafiee ◽  
Seyedeh Marzieh Hosseini
Keyword(s):  
Carbon Nanotubes ◽  
Frequency Response ◽  
Distribution Pattern ◽  
Temperature Change ◽  
Elastic Foundation ◽  
Forced Vibration ◽  
Natural Frequencies ◽  
Composite Beams ◽  
Vibration Response ◽  
Nano Composite

AbstractThis paper presents an analytical solution for nonlinear free and forced vibration response of smart laminated nano-composite beams resting on nonlinear elastic foundation and under external harmonic excitation. The structure is under a temperature change and an electric excitation through the piezoelectric layers. Different distribution patterns of the single walled aligned and straight carbon nanotubes (SWCNTs) through the thickness of the beam are considered. The beam complies with Euler-Bernoulli beam theory and von Kármán geometric nonlinearity. The nonlinearity is due to the mid-plane stretching of the beam and the nonlinear stiffness of the elastic foundation. The Multiple Time Scales perturbation scheme is used to perform the nonlinear dynamical analysis of functionally graded carbon nanotube-reinforced beams. Analytical expressions of the nonlinear natural frequencies, nonlinear dynamic response and frequency response of the system in the case of primary resonance have been presented. The effects of different parameters including applied voltage, temperature change, beam geometry, the volume fraction and distribution pattern of the carbon nanotubes on the nonlinear natural frequencies and frequency-response curves are presented. It is found that the volume fractions of SWCNTs as well as their distribution pattern significantly change the behavior of the system.

scholarly journals Free and Forced Vibration Modes of the Human Fingertip

2021 ◽  
Vol 11 (12) ◽  
pp. 5709
Author(s):  
Gokhan Serhat ◽  
Katherine J. Kuchenbecker
Keyword(s):  
Forced Vibration ◽  
Three Dimensional ◽  
Element Model ◽  
Vibration Modes ◽  
Form And Function ◽  
Dimensional Finite Element ◽  
Deformable Bodies ◽  
Vibration Responses ◽  
Three Dimensional Finite Element ◽  
And Function

Computational analysis of free and forced vibration responses provides crucial information on the dynamic characteristics of deformable bodies. Although such numerical techniques are prevalently used in many disciplines, they have been underutilized in the quest to understand the form and function of human fingers. We addressed this opportunity by building DigiTip, a detailed three-dimensional finite element model of a representative human fingertip that is based on prior anatomical and biomechanical studies. Using the developed model, we first performed modal analyses to determine the free vibration modes with associated frequencies up to about 250 Hz, the frequency at which humans are most sensitive to vibratory stimuli on the fingertip. The modal analysis results reveal that this typical human fingertip exhibits seven characteristic vibration patterns in the considered frequency range. Subsequently, we applied distributed harmonic forces at the fingerprint centroid in three principal directions to predict forced vibration responses through frequency-response analyses; these simulations demonstrate that certain vibration modes are excited significantly more efficiently than the others under the investigated conditions. The results illuminate the dynamic behavior of the human fingertip in haptic interactions involving oscillating stimuli, such as textures and vibratory alerts, and they show how the modal information can predict the forced vibration responses of the soft tissue.

scholarly journals Component Mode Synthesis Method Applied to Acoustic Resonators in Ducts for Structural Vibration Analysis

2020 ◽  
Vol 25 (4) ◽  
pp. 498-503
Author(s):  
Jose Manuel Bautista Ordóñez ◽  
Maria Alzira de Araújo Nunes
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Component Mode Synthesis ◽  
Structural Vibration ◽  
Structural Systems ◽  
Vibration Modes ◽  
The Finite Element Method ◽  
Element Method

Tubular structural systems appear in many industrial applications, such as heating, ventilation, and air conditioning systems, which are responsible for making any enclosed environment remain within a temperature, humidity, and cleanliness range. This kind of system has its applications in the internal environmental comfort of industrial spaces, buildings, and vehicles. Several of these spaces have industrial processes that generate high sound frequencies and mechanical vibrations that need to be adequately controlled to meet both environmental and health norms. With the intention to analyze the structural vibration of tubular systems, the modal analysis technique is a classical methodology for the extraction of natural frequencies and vibration modes. Among the various techniques of modal analysis, numerical methodologies such as the finite element method, and also analytical methodologies such as the Component Mode Synthesis (CMS) can be found. CMS is one of the leading modeling tools for complex systems that are applied to large systems. The method uses a modal superset and consists of separately modeling individual components of a structure and coupling them into a single system. The objective of this work is to demonstrate the application of the CMS technique through the estimation of natural frequencies and vibration modes in a simplified tubular structural system formed by two substructures, using MATLAB and ANSYS. The validation of the results was done through numerical modeling using the finite element method using and ANSYS software. The results obtained were satisfactory, thus demonstrating the feasibility of applying the CMS technique to an analysis of structural vibration in tubular structural systems.

scholarly journals Active Vibration-Based Condition Monitoring of a Transmission Line

Actuators ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 309
Author(s):  
Liuhuo Wang ◽  
Chengfeng Liu ◽  
Xiaowei Zhu ◽  
Zhixian Xu ◽  
Wenwei Zhu ◽  
...  
Keyword(s):  
Natural Frequencies ◽  
Engineering Application ◽  
Vibration Response ◽  
Modal Identification ◽  
Wireless Sensor ◽  
Transmission Tower ◽  
Transmission Towers ◽  
Vibration Responses ◽  
Active Vibration ◽  
Settlement Experiment

In the power system, the transmission tower is located in a variety of terrains. Sometimes there will be displacement, inclination, settlement and other phenomena, which eventually lead to the collapse of the tower. In this paper, a method for monitoring the settlement of a transmission tower based on active vibration response is proposed, which is based on the principle of modal identification. Firstly, a device was designed, which includes three parts: a monitoring host, wireless sensor and excitation device. It can tap the transmission tower independently and regularly, and collect the vibration response of the transmission tower. Then, vibration analysis experiments were used to validate the horizontal vibration responses of transmission towers which can be obtained by striking the transmission towers from either the X direction or Y direction. It can be seen from the frequency response function that the natural frequencies obtained from these two directions are identical. Finally, the transmission tower settlement experiment was carried out. The experimental results show that the third to fifth natural frequencies decreased most obviously, even up to 2.83 Hz. Further, it was found that under different conditions, as long as the tower legs adjacent to the excitation position settle, the natural frequency will decrease more significantly, which is very helpful for engineering application.

scholarly journals Structural Modeling and Modal Analysis of Hot-line Work Across the Line Construction

2018 ◽  
Vol 232 ◽  
pp. 02011
Author(s):  
Li Xu ◽  
Yanyi Fu ◽  
Hui Li ◽  
Lihua Xiao ◽  
Hao Guo ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Natural Frequencies ◽  
Vibration Modes ◽  
Nonlinear Structures ◽  
The Finite Element Method ◽  
Transient Dynamic Analysis ◽  
Initial Shape ◽  
Line Construction ◽  
Line Work

For the nonlinear structures such as traverse and mesh spanning structure, it is very difficult to analyze the traditional calculation method. The initial shape of the structure is determined by the finite element method and the accuracy of the model is verified. Based on this model, the natural frequencies and vibration modes of the structure are analyzed and determined, which can provide reference for transient dynamic analysis.

scholarly journals VIBRATION STUDY OF MAGNETORHEOLOGICAL FLUID FILLED SANDWICH BEAMS

2012 ◽  
pp. 76-80
Author(s):  
SHRIKANT B. JOSHI
Keyword(s):  
Magnetic Fields ◽  
Forced Vibration ◽  
Fluid Layer ◽  
Research Work ◽  
Flexible Structures ◽  
Vibration Response ◽  
Sandwich Beams ◽  
Mr Fluid ◽  
Vibration Responses ◽  
And Shifts

The concept of vibration mitigation in flexible structures using smart fluids has attracted researcher’s interest in the last few years. Significant research work has been done on the structures with electrorheological fluids, but there has been a little work with the magnetorheological fluids. This study investigates the vibration controllability of MR fluid filled cantilever beams under externally applied magnetic fields. The adaptive structures were fabricated by adding a MR fluid layer between the adjacent elastic layers and the properties of two different types of sandwich beams were studied. In the first type, free and forced vibration responses of aluminium beam with partial treatment were evaluated and compared with fully filled beam. The controllability of vibration response was observed in terms of variations in vibration amplitudes and shifts in magnitudes of the resonant natural frequency. In second type, a composite cylindrical sandwich cantilever beam with end plate was fabricated. It consisted of outer stainless steel hollow pipe with end mass, inner wooden rod and an embedded MR fluid. Inner rods with different diameters were used to vary the thickness of MR fluid layer. Forced vibration response of such beams exhibited increased damping under increased magnetic fields.

scholarly journals New Finite Modeling of Free and Forced Vibration Responses of Piezoelectric FG Plates Resting on Elastic Foundations in Thermal Environments

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Pham Minh Phuc ◽  
Nguyen Thi Kim Khue
Keyword(s):  
Forced Vibration ◽  
Volume Fraction ◽  
Shear Deformation Theory ◽  
The Finite Element Method ◽  
Third Order ◽  
Elastic Foundations ◽  
Thermal Environments ◽  
Fg Plates ◽  
Vibration Responses ◽  
Forced Vibration Analysis

This paper carries out free and forced vibration analysis of piezoelectric FGM plates resting on two-parameter elastic foundations placed in thermal environments. By employing the third-order shear deformation theory and the finite element method, this work establishes free and forced vibration equations of piezoelectric FGM plates, where the materials are assumed to be varied in the thickness directions, and the mechanical properties depend on the temperature. Then, comparative examples are conducted to verify the proposed theory and mathematical model, and the results of this study and other methods meet a very good agreement. Then, effects of geometrical and material properties such as the feedback coefficient, voltage, volume fraction index, temperature as well as the parameters of elastic foundations on free and forced vibration of the plates are investigated, and the conclusions are given out to provide the effective direction for the design and practical use of these structures.

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