Abstract
On the basis of the explicit time-domain method, an investigation is performed on the influence of the rotational stiffness and rotational damping of the vehicle body and front-rear bogies on the dynamic responses of the vehicle-bridge coupled systems. The equation of motion for the vehicle subsystem is derived employing rigid dynamical theories without considering the rotational stiffness and rotational damping of the vehicle body, as well as the front-rear bogies. The explicit expressions for the dynamic responses of the vehicle and bridge subsystems to contact forces are generated utilizing the explicit time-domain method. Due to the compact wheel-rail model, which reflects the compatibility requirement of the two subsystems, the explicit expression of the evolutionary statistical moment for the contact forces may be performed with relative ease. Then, the evolutionary statistical moments for the respective responses of the two subsystems can be determined. The numerical results indicate that the simplification of vehicle model has little effect on the responses of the bridge subsystem and the vehicle body, except for the responses of the rotational degrees of freedom for the vehicle subsystem, regardless of whether deterministic or random analyses are performed.
Key Words
explicit time-domain method; random vibration analysis; simplified vehicle model; vehiclebridge coupled system
Address
Huan Huang, Yuyu Li, Wenxiong Li and Guihe Tang: College of Water Conservancy and Civil Engineering, South China Agricultural University, Guangzhou 510642, P.R. China
Abstract
In this study, the vibration problem of thermo elastic carbon nanotubes conveying pulsating viscous nano
fluid subjected to a longitudinal magnetic field is investigated via Euler-Bernoulli beam model. The controlling
partial differential equation of motion is arrived by adopting Eringen's non local theory. The instability domain and pulsation frequency of the CNT is obtained through the Galerkin's method. The numerical evaluation of this study is
devised by Haar wavelet method (HWM). Then, the proposed model is validated by analyzing the critical buckling
load computed in present study with the literature. Finally, the numerical calculation of system parameters are shown
as dispersion graphs and tables over non local parameter, magnetic flux, temperature difference, Knudsen number
and viscous parameter.
Key Words
dynamic stability; Haar wavelet method; Knudsen number; nonlocal parameter; pulsating nano
flow; viscous fluid
Address
R. Selvamani: Department of Mathematics, Karunya University, Coimbatore, 641 114, Tamil Nadu, India
M. Mahaveer Sree Jayan: Department of Mathematics, Indra Ganesan College of Engineering, Tiruchirappalli, 620012, Tamilnadu, India
Marin Marin: Department of Mathematics and Computer Science, Transilvania University of Brasov, Romania
Abstract
The present work is concerned with the study of the influence of inhomogeneous initial stresses in a hollow cylinder containing a compressible inviscid fluid on the propagation of axisymmetric longitudinal waves propagating in this cylinder. The study is carried out using the so-called three-dimensional linearized theory of elastic waves in bodies with initial stresses to describe the motion of the cylinder and using the linearized Euler equations to describe the flow of the compressible inviscid fluid. It is assumed that the inhomogeneous initial stresses in the cylinder are caused by the internal pressure of the fluid. To solve the corresponding eigenvalue problem, the discreteanalytic solution method is applied and the corresponding dispersion equation is obtained, which is solved numerically, after which the corresponding dispersion curves are constructed and analyzed. To obtain these dispersion curves, parameters characterizing the magnitude of the internal pressure, the ratio of the sound velocities in the cylinder material and in the fluid, and the ratio of the material densities of the fluid and the cylinder are introduced. Based on these parameters, the influence of the inhomogeneous initial stresses in the cylinder on the dispersion of the above-mentioned waves in the considered hydro-elastic system is investigated. Moreover, based on these results, appropriate conclusions about this influence are drawn. In particular, it is found that the character of the influence depends on the wavelength. Accordingly, the inhomogeneous initial stresses before (after) a certain value of the wavelength lead to a decrease (increase) of the wave propagation velocity in the zeroth and first modes.
Address
Surkay D. Akbarov: Department of Mechanical Engineering, Yildiz Technical University, 34349, Besiktas, Istanbul, Turkey; Institute of Mathematics and Mechanics of the National Academy of Sciences of Azerbaijan,
AZ1141, Baku, Azerbaijan
Gurbaneli J. Veliyev: Baku State University, Baku, Azerbaijan
Abstract
This paper considers a delamination analysis of a statically undetermined inhomogeneous beam structure of rectangular section with viscoelastic behavior under torsion. The beam is built in at its two ends. The beam has two longitudinal inhomogeneous layers with a delamination crack between them. A notch is made in the upper crack arm. The external torsion moment applied on the beam is a function of time. Under these conditions, the beam has one degree of indeterminacy. In order to derive the strain energy release rate, first, the static indeterminacy is resolved. Then the strain energy release rate is obtained by analyzing the balance of the energy with considering the viscoelastic behavior. The strain energy release rate is found also by analyzing the compliance of the beam for checkup. Solution of the strain energy release rate in a beam without a notch in the upper crack arm is derived too. In this case, the beam has two degrees of static indeterminacy (the torsion moment in the upper crack arm is treated as an additional internal redundant unknown). A parametric investigation of the strain energy release rate is carried-out.
Key Words
delamination; inhomogeneous beam structure; rectangular section; torsion moment; viscoelastic material
Address
Victor I. Rizov: Department of Technical Mechanics, University of Architecture, Civil Engineering and Geodesy, 1 Chr. Smirnensky Blvd., 1046-Sofia, Bulgaria
Abstract
First introduced in 2016, the dynamic foundation model is an interesting topic in which the foundation is described close to reality by taking into account the influence of the foundation mass in the calculation of oscillation and is an important parameter that should be considered. In this paper, a follow-up investigation is conducted with the object of the Mindlin plate on a nonlinear dynamic foundation under moving loads. The base model includes nonlinear elastic springs, linear Pasternak parameters, viscous damping, and foundation mass. The problem is formulated by the finite element analysis and solved by the Newmark-B method. The displacement results at the center of the plate are analyzed and discussed with the change of various parameters including the nonlinear stiffness, the foundation mass, and the load velocity. The dynamic response of the plate sufficiently depends on the foundation mass.
Key Words
dynamic analysis; foundation mass; moving load; nonlinear dynamic foundation model; plate on foundation
Address
Phuoc T. Nguyen, Thieu V. Vi, Tuan T. Nguyen: Faculty of Civil Engineering, Ho Chi Minh City Open University, 97 Vo Van Tan, Ho Chi Minh City 700000, Vietnam
Van T. Vu: Department of Civil Engineering, Ho Chi Minh City University of Achitecture, 196 Pasteur, Ho Chi Minh City 700000, Vietnam
