Jaafar Hallal^1,2,3,*, Mohammad Hammoud^2,3, Mahmoud Fakih^2,3,4, Ali Hallal^2,3

Sound & Vibration, Vol.54, No.4, pp. 225-236, 2020, DOI:10.32604/sv.2020.011513

Abstract The vibrations behavior analysis is an essential step in the mechanical design process. Several methods such as analytical modelling, numerical analysis and experimental measurements can be used for this purpose. However, the numerical or analytical models should be validated through experimental measurements, usually expensive. This paper introduces an inexpensive smartphone as an accurate, non-intrusive vibrations’ behavior measurement device. An experimental measurement procedure based on the video processing method is presented. This procedure allows the measurement of the natural frequencies and the mode shapes of a vibrating structure, simply by using a smartphone built-in camera. The experimental results are compared to… More >

Y. A. Amer¹, A. T. El-Sayed², M. N. Abd El-Salam^3,*

Sound & Vibration, Vol.54, No.3, pp. 149-161, 2020, DOI:10.32604/sv.2020.08469

Abstract In this paper, we used time delay feedback to minimize the vibrations of a hybrid Rayleigh–van der Pol–Duffing oscillator. This system is a one-degree-offreedom containing the cubic and fifth nonlinear terms and an external force. We applied the multiple scales method to get the solution from first approximation. Graphically and numerically, we studied the system before and after adding time delay feedback at the primary resonance case (Ω ≌ ω). We used MATLAB program to simulate the efficacy of different parameters and the time delay on the main system. More >

E. Viola¹, F. Tornabene²

Structural Durability & Health Monitoring, Vol.1, No.2, pp. 155-170, 2005, DOI:10.3970/sdhm.2005.001.155

Abstract In this paper, generalized differential quadrature techniques are applied to the computation of the in-plane free vibrations of thin and thick non-uniform circular arches in undamaged and damaged configurations, when various boundary conditions are considered. Structural damage is represented by one crack in different positions and with various damage levels. The crack present in a structural member can be considered as a local stiffness reduction at the fracturing section, which changes the dynamic behaviour of the structure. Much effort has been devoted to dealing with in-plane free vibration analysis of circular arches, but only a few researchers have studied cracked… More >

V.G. Kozlov^1,2, A.A. Ivanova³, P. Evesque¹

FDMP-Fluid Dynamics & Materials Processing, Vol.2, No.3, pp. 203-210, 2006, DOI:10.3970/fdmp.2006.002.203

Abstract Sedimentation of granular matter in a vertical channel filled with a viscous liquid and subject to longitudinal translational vibration is studied, starting froma compact suspension. A new vibrational effect is foundexperimentally and described theoretically; it is the formation of blocks (with a relatively high density) of sedimenting granular matter with stable lower and upper horizontal demarcations and a sharp density discontinuity. Owing to this phenomenon the sedimentation velocity of such granular matter is reduced. A new theoreticalmodel based on viscous vibrational particle interactionin the limit of concentrated suspensions is elaborated, assuming particle-particle attraction in direction parallel tovibration and particle-particle repulsion… More >

K.C. Chuang, C.C. Ma, C.H. Wang

The International Conference on Computational & Experimental Engineering and Sciences, Vol.19, No.1, pp. 1-2, 2011, DOI:10.3970/icces.2011.019.001

Abstract Smart flexible structures involve four key elements: actuators, sensors, control strategies, and power conditioning electronics, which makes the structures being capable of realizing specific functions. Recently, fiber Bragg grating (FBG) strain sensors are being considered to be integrated into smart structures since they possess many excellent properties such as low density, small size, simplicity of fabrication, and immunity to electromagnetic fields. In this paper, unlike traditional FBG strain sensors, a fiber Bragg grating (FBG) sensing system which has the ability to detect point-wise out-of-plane displacement responses is set up on a smart cantilever beam to perform active vibration control. The… More >

A. Alaimo¹, A. Milazzo¹, C. Orlando¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.15, No.4, pp. 137-144, 2010, DOI:10.3970/icces.2010.015.137

Abstract The axial and flexural natural frequencies of magneto-electro-elastic bimorph beam devices are analyzed in the framework of the third-order shear deformation theory (TSDT). Although the assumption of parabolic transverse shear strain distribution along the thickness leads to higher order stress resultants the use of the TSDT allows to avoid the need for shear correction factor. Moreover, since the electric and magnetic potentials strictly depend on the shear strains, a more accurate modeling of the magneto-electric coupling can be achieved by expanding the kinematical model up to the cubic term. The natural frequencies for different mechanical boundary conditions are computed by… More >

G. Geethanjali^∗, C. Sujatha^†

Molecular & Cellular Biomechanics, Vol.10, No.4, pp. 303-317, 2013, DOI:10.3970/mcb.2013.010.303

Abstract This paper reports a study on the biomechanical response of a human hand-arm model to random vibrations of the steering wheel of a tractor. An anatomically accurate bone-only hand-arm model from TurboSquidTM was used to obtain a finite element (FE) model to understand the Hand-arm vibration syndrome (HAVS), which is a neurological and vascular disorder caused by exposure of the human hand-arm to prolonged vibrations. Modal analysis has been done to find out the first few natural frequencies and mode shapes of the system. Coupling of degrees of freedom (DOF) had to be done in the FE idealization to do… More >

Huaxi Lu^1,*, Zhicheng Gao¹, Luyao Xu¹, Bitao Wu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.1, pp. 177-205, 2019, DOI:10.31614/cmes.2019.04169

Abstract The railway environmental vibration caused by high-speed railways is harmful to the human health, the structural safety of adjacent buildings, and the normal use of precision instruments. At the same time, it occurs frequently. In this case, the railway environmental vibration has drawn much attention with the rapid development of high-speed railways. Studies in Earthquake Engineering show that a convex topography has a great impact on ground vibrations, however, there is no consideration about the convex topographic effect in the study of the railway environmental vibration when the convex topography is near the roadway. In this paper, the influence of… More >

F. S. Bayones¹, A. M. Abd-Alla²

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.2, pp. 151-170, 2017, DOI:10.3970/cmes.2017.113.155

Abstract The aim of this paper is to study the effects of rotation and magnetic field on the plane vibrations in a transversely isotropic material of an infinite hollow cylinder. The natural frequency of the plane vibrations in the case of harmonic vibrations has been obtained. The natural frequencies are calculated numerically and the effects of rotation and magnetic field are discussed. The numerical results obtained have been illustrated graphically to understand the behavior of frequency equation with different values of frequency under effects the rotation and magnetic field. Comparison was made with the results obtained in the presence and absence… More >

Salvatore Brischetto¹

CMES-Computer Modeling in Engineering & Sciences, Vol.104, No.4, pp. 305-327, 2015, DOI:10.3970/cmes.2015.104.305

Abstract This paper proposes the free vibration analysis of Double-Walled Carbon NanoTubes (DWCNTs). A continuum elastic three-dimensional shell model is used for natural frequency investigation of simply supported DWCNTs. The 3D shell method is compared with beam analyses to show the applicability limits of 1D beam models. The effect of van der Waals interaction between the two cylinders is shown for different Carbon NanoTube (CNT) lengths and vibration modes. Results give the van der Waals interaction effect in terms of frequency values. In order to apply the 3D shell continuum model, DWCNTs are defined as two concentric isotropic cylinders (with an… More >