S.D. Akbarov^1,2, E. Hazar³, M. Eröz³

CMC-Computers, Materials & Continua, Vol.36, No.1, pp. 23-48, 2013, DOI:10.3970/cmc.2013.036.023

Abstract Within the scope of the piecewise homogeneous body model with utilizing of the three dimensional linearized theory of elastic waves in initially stressed bodies the influence of the shear-spring type imperfection of the contact conditions between the layers of the pre-stressed bi-layered plate strip resting on the rigid foundation, on the frequency response of this plate strip is investigated. The corresponding mathematical problem is solved numerically by employing FEM and numerical results illustrating the influence of the parameter characterizing the degree of the mentioned imperfectness, on the frequency response of the normal stress acting on More >

L. Solazzi^1,2, C. Petrogalli¹, M. Lancini¹

Structural Durability & Health Monitoring, Vol.8, No.4, pp. 329-340, 2012, DOI:10.32604/sdhm.2012.008.329

Abstract A study on vibrations related to rolling contact fatigue test bench and a possible way to correlate this mechanical behavior and damage of the specimens is presented. In particular it has been evaluated the possibility to detect and quantify, thanks to vibration analysis, the damage on two discs subjected to rolling contact fatigue in different working conditions. Paper is divided in two parts. In the first part there is a description of test bench and results of its static and modal analyses. Then, some tests were carried out changing working conditions and specimens' parameters and More >

S.D. Akbarov^1,2, N. Yahnioglu³, U. Babuscu Yesil³

CMC-Computers, Materials & Continua, Vol.28, No.2, pp. 147-164, 2012, DOI:10.3970/cmc.2012.028.147

Abstract This paper presents an analysis of the forced vibration of an initially stressed rectangular composite plate containing two neighboring cylindrical cavities. The initial stresses are caused by stretching or compressing of the plate with uniformly distributed normal static forces acting on the two opposite end-planes which are parallel to the central axes of the aforementioned cylindrical cavities. The influence of the initial stresses on the stress concentration around the cavities caused by the additional uniformly distributed time harmonic forces acting on the upper face plane of the plate are given. The considered problem is formulated More >

De-Shin Liu^1,2, Chin-Yi Tu¹, Cho-Liang Chung³

CMC-Computers, Materials & Continua, Vol.28, No.2, pp. 97-120, 2012, DOI:10.3970/cmc.2012.028.097

Abstract Manufacturing defects in the membrane of MEMS (Micro-Electro-Mechanical-Systems) structures have a significant effect on the sensitivity and working range of the device. Thus, in optimizing the design of MEMS devices, it is essential that the effects of membrane defects (e.g., cracks) can be predicted in advance. Accordingly, this study proposes the detailed two-dimensional Infinite Element Method (IEM) formulation with Infinite Element (IE)-Finite Element (FE) coupling scheme for analyzing the out-of-plane vibration of isotropic MEMS membranes containing one or more tip cracks. In the proposed approach, a degenerative computation scheme is used to condense the multiple… More >

A.S Vinod Kumar, Ranjan Ganguli²

CMES-Computer Modeling in Engineering & Sciences, Vol.88, No.6, pp. 443-474, 2012, DOI:10.3970/cmes.2012.088.443

Abstract The governing differential equation of a rotating beam becomes the stiff-string equation if we assume uniform tension. We find the tension in the stiff string which yields the same frequency as a rotating cantilever beam with a prescribed rotating speed and identical uniform mass and stiffness. This tension varies for different modes and are found by solving a transcendental equation using bisection method. We also find the location along the rotating beam where equivalent constant tension for the stiff string acts for a given mode. Both Euler-Bernoulli and Timoshenko beams are considered for numerical results. More >

Biao Zhou^1,2,3, Xiong yao Xie^1,2, Yeong Bin Yang⁴, Jing Cai Jiang³

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.4, pp. 321-348, 2012, DOI:10.3970/cmes.2012.086.321

Abstract The vibration-based SHM (Structure Health Monitoring) system has been successfully used in bridge and other surface civil infrastructure. However, its application in operation tunnels remains a big challenge. The reasons are discussed in this paper by comparing the vibration characteristics of the free tunnel structure and tunnel-soil coupled system. It is revealed that all the correlation characteristics of the free tunnel FRFs (Frequency Response Function spectrum) will vanish and be replaced by a coupled resonance frequency when the tunnel is surrounded by soil. The above statement is validated by field measurements. Moreover, the origin of More >

V.G.Yakhno¹, D. Ozdek²

CMES-Computer Modeling in Engineering & Sciences, Vol.85, No.2, pp. 157-176, 2012, DOI:10.3970/cmes.2012.085.157

Abstract The present paper describes computation of the time-dependent Green's function for the equations of longitudinal vibration of a multi-step rod with a piecewise constant varying cross-section. This computation is based on generalization of the Fourier series expansion method. The time-dependent Green's function is derived in the form of the Fourier series. The basic functions of this series are eigenfunctions of an ordinary differential equation with boundary and matching conditions. Constructing the eigenvalues and eigenfunctions of this differential equation and then derivation of the Fourier coefficients of the Green's function are main steps of the method. More >

Zhibo Yang¹, Xuefeng Chen², Bing Li¹, Zhengjia He¹, Huihui Miao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.85, No.2, pp. 129-156, 2012, DOI:10.3970/cmes.2012.085.129

Abstract The implementation of the B-spline Wavelet on the Interval (BSWI) for curved shell elements with rectangular planform is presented in this paper. By aid of the general shell theory, cylinder shells, doubly-curved shallow shells and hyperbolic paraboloidal shells BSWI elements are formulated. Instead of traditional polynomial interpolation, scaling functions at certain scale have been adopted to form the shape functions and construct wavelet-based elements. Because of the good character of BSWI scaling functions, the BSWI curved shell elements combine the accuracy of wavelet-based elements approximation and the character of B-spline functions for structural analysis. Different More >

M.G. Armentano¹, C. Padra², R. Rodríguez³, M. Scheble²

CMES-Computer Modeling in Engineering & Sciences, Vol.84, No.4, pp. 359-382, 2012, DOI:10.3970/cmes.2012.084.359

Abstract In this paper we propose an hp finite element method to solve a two-dimensional fluid-structure vibration problem. This problem arises from the computation of the vibration modes of a bundle of parallel tubes immersed in an incompressible fluid. We use a residual-type a posteriori error indicator to guide an hp adaptive algorithm. Since the tubes are allowed to be different, the weak formulation is a non-standard generalized eigenvalue problem. This feature is inherited by the algebraic system obtained by the discretization process. We introduce an algebraic technique to solve this particular spectral problem. We report More >

A.H. Ahadi¹, M.Z. Saghir¹

FDMP-Fluid Dynamics & Materials Processing, Vol.8, No.4, pp. 397-422, 2012, DOI:10.3970/fdmp.2012.008.397

Abstract The numerical simulations of a thermodiffusion experiment in atmospheric pressure binary mixtures of water and isopropanol subject to micro-vibrations at reduced gravity are presented. The vibrations are induced on board ISS and FOTON-M3 due to many different reasons like crew activity, spacecraft docking or operating other experiments, etc. The effects of micro-gravity vibration were investigated in detail on all of the mixture properties. The influences of different cavity sizes as well as different signs of Soret coefficients in the solvent were considered. In this paper, the thermodiffusion experiment was subjected to two different g-jitter vibrations… More >