scholarly journals A Single and Double Mode Approach to Chaotic Vibrations of a Cylindrical Shell with Large Deflection

2004 ◽  
Vol 11 (5-6) ◽  
pp. 533-546 ◽  
Author(s):  
Liming Dai ◽  
Qiang Han ◽  
Mingzhe Dong
Keyword(s):  
Cylindrical Shell ◽  
Large Deflection ◽  
Single Mode ◽  
Order Mode ◽  
Governing Equations ◽  
Chaotic Vibrations ◽  
Nonlinear Dynamic Equations ◽  
Different Types ◽  
Mode Method ◽  
Research Show

The chaotic vibrations of a cylindrical shell of large deflection subjected to two-dimensional exertions are studied in the present research. The dynamic nonlinear governing equations of the cylindrical shell are derived on the basis of single and double mode models established. Two different types of nonlinear dynamic equations are obtained with varying dimensions and loading parameters. The criteria for chaos are determined via Melnikov function for the single mode model. The chaotic motion of the cylindrical shell is investigated and the comparison between the single and double mode models is carried out. Results of the research show that the single mode method usually used may lead to incorrect conclusions under certain conditions. Double mode or higher order mode methods should be used in these cases.

Stick-Slip Vibrations of Layered Structures Undergoing Large Deflection and Dry Friction at the Interface

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Hamid M. Sedighi ◽  
Kourosh H. Shirazi ◽  
Khosro Naderan-Tahan
Keyword(s):  
Dry Friction ◽  
Large Deflection ◽  
Dynamical Behavior ◽  
Single Mode ◽  
Layered Structures ◽  
Order Mode ◽  
Chaotic Motions ◽  
Stick Slip ◽  
Coupled Equations ◽  
Mode Method

The present study focuses on the nonlinear analysis of the dynamical behavior of layered structures, including interfacial friction in the presence of the stick-slip phenomenon and large deformation. To achieve a proper outlook for the two-layer structure's behavior, it is essential to precisely realize the mechanisms of motion. Taking the dry friction into account, coupled equations of the transversal and longitudinal large vibration of two-layers are derived and nondimensionalized. Furthermore, the free and forced vibration of the aforementioned system is investigated. From the results of the numerical simulation, it is observed that there exist quasi-periodic and stick–slip chaotic motions in the system. The results demonstrate that the single mode method usually utilized may lead to incorrect conclusions and, instead, the higher order mode method should be employed. A comparative study with ANSYS is developed to verify the accuracy of the proposed approach.

BIFURCATION AND CHAOTIC MOTION OF AN ELASTIC PLATE OF LARGE DEFLECTION UNDER PARAMETRIC EXCITATION

2005 ◽  
Vol 15 (09) ◽  
pp. 2849-2863
Author(s):  
Q. HAN ◽  
L. DAI ◽  
M. DONG
Keyword(s):  
Large Deflection ◽  
Single Mode ◽  
Harmonic Excitation ◽  
Governing Equations ◽  
External Excitation ◽  
Mode Method ◽  
Elastic Rectangular Plate ◽  
The Stability ◽  
Nonlinear Elastic ◽  
Bifurcation Behavior

The dynamic behavior of a nonlinear elastic rectangular plate of large deflection subjected to harmonic excitation is investigated. Using the Galerkin principle, a double mode model is established for the plate. The stability and bifurcation behavior of the plate is studied in detail for various loading conditions and system parameters. A set of autonomous equations is derived with the method of averaging. The bifurcation behavior is examined on the basis of the autonomous equations, and the results of theoretical bifurcation analysis are numerically verified. The chaotic response of the plate to the external excitation is also investigated. The governing equations of single as well as double modes are established and the comparison between the single and double mode models is carried out. The applicable conditions of the single mode method are provided. The results obtained show that the single mode approach usually used may lead to incorrect conclusions under certain conditions.

scholarly journals The Influence of Different Types of Nanofluid on Thermal and Fluid Flow Performance of Liquid Cold Plate

2018 ◽  
Vol 7 (4.35) ◽  
pp. 148 ◽  
Author(s):  
Nur Irmawati Om ◽  
Rozli Zulkifli ◽  
P. Gunnasegaran
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Steady State ◽  
Pressure Drop ◽  
Volume Fraction ◽  
Cold Plate ◽  
Governing Equations ◽  
Flow And Heat Transfer ◽  
Different Types ◽  
Volume Method

The influence of utilizing different nanofluids types on the liquid cold plate (LCP) is numerically investigated. The thermal and fluid flow performance of LCP is examined by using pure ethylene glycol (EG), Al2O3-EG and CuO-EG. The volume fraction of the nanoparticle for both nanofluid is 2%. The finite volume method (FVM) has been used to solved 3-D steady state, laminar flow and heat transfer governing equations. The presented results indicate that Al2O3-EG able to provide the lowest surface temperature of the heater block followed by CuO-EG and EG, respectively. It is also found that the pressure drop and friction factor are higher for Al2O3-EG and CuO-EG compared to the pure EG.

Bifurcation analysis of two-dimensional laminar flow through sudden expansion channel

2022 ◽  
Vol 13 (1) ◽  
pp. 0-0
Keyword(s):  
Laminar Flow ◽  
Expansion Ratio ◽  
Sudden Expansion ◽  
Two Dimensional ◽  
Governing Equations ◽  
Bifurcation Phenomena ◽  
Different Types ◽  
Fluent Software ◽  
Flow Through ◽  
Volume Method

In this work, bifurcation characteristics of unsteady, viscous, Newtonian laminar flow in two-dimensional sudden expansion and sudden contraction-expansion channels have been studied for different values of expansion ratio. The governing equations have been solved using finite volume method and FLUENT software has been employed to visualize the simulation results. Three different mesh studies have been performed to calculate critical Reynolds number (Recr) for different types of bifurcation phenomena. It is found that Recr decreases with the increase in expansion ratio (ER).

Low-noise blue light generation of intracavity frequency-doubled LD-pumped Cr:LiSAF laser by single-mode method

2001 ◽  
Vol 138 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Satoshi Makio ◽  
Hironari Matsumoto ◽  
Akio Miyamoto ◽  
Masayoshi Sato ◽  
Takatomo Sasaki
Keyword(s):  
Blue Light ◽  
Single Mode ◽  
Low Noise ◽  
Intracavity Frequency ◽  
Mode Method ◽  
Light Generation

Innovation in the aftermath of downsizing: evidence from the threat-rigidity perspective

2020 ◽  
Vol 49 (9) ◽  
pp. 1859-1877
Author(s):  
José Fernández-Menéndez ◽  
Óscar Rodríguez-Ruiz ◽  
José-Ignacio López-Sánchez ◽  
María Isabel Delgado-Piña
Keyword(s):  
Regression Models ◽  
Negative Impact ◽  
Content Type ◽  
Logistic Regression Models ◽  
Marketing Innovation ◽  
Different Types ◽  
Threat Rigidity ◽  
The Impact ◽  
Research Show ◽  
Innovation Outcomes

PurposeThe purpose of this paper is to study how job reductions affect product innovation and marketing innovation in a sample of 2,034 Spanish manufacturing firms in the period 2007–2014.Design/methodology/approachPoisson and logistic regression models with random effects were used to analyse the impact of downsizing on some innovation outcomes of firms.FindingsThe results of this research show that the stressful measure of job reductions may have unexpected consequences, stimulating innovation. However downsizing combined with radical organisational changes such as new equipment, techniques or processes seems to have a negative impact on product and marketing innovation.Originality/valueThis research has two original features. First, it explores the unconventional direction of causality from the planned elimination of jobs to innovation outputs. Secondly, the paper looks at the combined effect of downsizing and other restructuring measures on different types of innovation. Following the threat-rigidity theory, we assume that this combination represents a major threat for survivors that leads to lower levels of product and marketing innovation.

scholarly journals Study on Heterogeneity of Pore Throats at Different Scales and Its Influence on Seepage Capacity in Different Types of Tight Carbonate Reservoirs

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Chunyan Qi ◽  
Yun Liu ◽  
Fengjuan Dong ◽  
Xixiang Liu ◽  
Xing Yang ◽  
...  
Keyword(s):  
Fractal Theory ◽  
Single Mode ◽  
Scientific Basis ◽  
Carbonate Reservoirs ◽  
Pore Throat ◽  
Gas Reservoir ◽  
Thin Sections ◽  
Different Types ◽  
Tight Carbonate ◽  
Efficient Exploration

The carbonate reservoirs in the middle Sichuan area have undergone complicated tectonics, resulting in various types of reservoir space, large secondary changes, and multiple complexities. Taking the tight carbonate gas reservoir of the Deng-4 member in this area as an example, based on casting thin sections, scanning electron microscopy, and high-pressure mercury injection experiments, the reservoir space and microstructural characteristics of the micropore throats were studied, and the influence of the microscale heterogeneity in different types of reservoirs on the seepage capacity was analyzed by applying fractal theory. The results showed that the reservoir space in the tight carbonate rock of the Deng-4 member in the study area could be divided into 3 types: pore-hole-fracture, pore-hole, and pore types. The distribution characteristics of the pore throat diameter were multimode wide type, double-mode high and low asymmetrical type, and single-mode concentrated type. The fractal dimension and seepage capability of the pore throat increased successively in sizes from less than 0.1 μm to 0.1~1.0 μm and greater than 1.0 μm. On the one hand, the development of karst caves and fractures controlled the percolation ability of tight carbonate reservoirs; on the other hand, it enhanced the heterogeneity of the micropore throat structure. However, the development degree of dissolved pores and microfractures has a weak contribution to the connectivity and seepage capacity of the reservoir space. Acidification, fracturing, and other measures can be adopted to enhance the connectivity between pores to improve the productivity of the gas reservoir. This study provides a scientific basis for the efficient exploration and development of tight carbonate reservoirs.

The Backing Design in the Free Damping Cylindrical Shell Damping Test

2013 ◽  
Vol 437 ◽  
pp. 475-480
Author(s):  
Bang Hui Yin ◽  
Min Qing Wang
Keyword(s):  
Cylindrical Shell ◽  
Energy Method ◽  
Design Problem ◽  
Loss Factor ◽  
Cylindrical Shells ◽  
Harmonic Response ◽  
Different Types ◽  
Damping Loss Factor

The ANSYS harmonic response results are post-processed with the energy method to obtain the damping loss factor (DLF) of different types of free damping structures. Firstly, the DLF of free damping cylindrical shell in air is compared with DLF of free damping plate in air. Secondly, the DLF of free damping cylindrical shell with stiffened ribs in air is compared with that without stiffened ribs in air. Thirdly, the DLF of free damping cylindrical shell in water is compared with the DLF of free damping plate in water. Fourthly, the DLF of free damping cylindrical shell with stiffened ribs in water is compared with that without stiffened ribs in water. In the end, based on the above analysis, the backing design problem in air and water are discussed. Studies have shown that: DLF of free damping cylindrical shell is close to that of free damping plate in air; DLF of free damping cylindrical shell with stiffened ring ribs is close to that without stiffened ring ribs in air; When testing free damping cylindrical shells DLF in air, plate with the same thickness can be used as the backing; DLF of free damping plate is close to that of free damping cylindrical shell in water; DLF of free damping cylindrical shell with stiffened ring ribs is close to that without stiffened ring ribs in water; When testing free damping cylindrical shells DLF in water, plate with the same thickness can be used as the backing.

Free Vibration of a Circular Cylindrical Shell Elastically Restrained by Axially Spaced Springs

1983 ◽  
Vol 50 (3) ◽  
pp. 544-548 ◽  
Author(s):  
T. Irie ◽  
G. Yamada ◽  
Y. Muramoto
Keyword(s):  
Cylindrical Shell ◽  
Free Vibration ◽  
Circular Cylindrical Shell ◽  
Frequency Equation ◽  
Mode Shapes ◽  
Governing Equations ◽  
Structure Matrix ◽  
The Matrix ◽  
Circular Cylindrical Shells ◽  
Elastically Restrained

An analysis is presented for the free vibration of a circular cylindrical shell restrained by axially spaced elastic springs. The governing equations of vibration of a circular cylindrical shell are written as a coupled set of first-order differential equations by using the transfer matrix of the shell. Once the matrix has been determined, the entire structure matrix is obtained by the product of the transfer matrices and the point matrices at the springs, and the frequency equation is derived with terms of the elements of the structure matrix under the boundary conditions. The method is applied to circular cylindrical shells supported by axially equispaced springs of the same stiffness, and the natural frequencies and the mode shapes of vibration are calculated numerically.

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