Yong Wang, Hongjian Ni^*, Ruihe Wang, Shubin Liu

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.5, pp. 1263-1273, 2022, DOI:10.32604/fdmp.2022.020405 - 27 May 2022

Abstract A specific model is elaborated for stick-slip and bit-bounce vibrations, which are dangerous dynamic phenomena typically encountered in the context of rotary drilling applications. Such a model takes into account two coupled degrees of freedom of drill-string vibrations. Moreover, it assumes a state-dependent time delay and a viscous damping for both the axial and torsional vibrations and relies on a sawtooth function to account for the cutting force fluctuation. In the frame of this theoretical approach, the influence of rock brittleness on the stability of the drill string is calculated via direct integration of the More >

Imran M. Jamadar^1,*, B. Suresha¹, Prasanta Kumar Samal¹, S. A. I. Bellary²

Sound & Vibration, Vol.56, No.2, pp. 165-191, 2022, DOI:10.32604/sv.2022.015267 - 25 March 2022

Abstract Usage of rolling contact bearings in variety of rotor-dynamic applications has put forth a need to develop a detailed and easy to implement techniques for the assessment of damage related features in these bearings so that before mechanical failure, maintenance actions can be planned well in advance. In accordance to this, a method based on dimensional amplitude response analysis and scaling laws is presented in this paper for the diagnosis of defects in different components of rolling contact bearings in a dimensionally scaled rotor-bearing system. Rotor, bearing, operating and defect parameters involved are detailed for… More >

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

Sound & Vibration, Vol.56, No.2, pp. 89-104, 2022, DOI:10.32604/sv.2022.011838 - 25 March 2022

Abstract In our consideration, a comparison between four different types of controllers for suppression the vibrations of the cantilever beam excited by an external force is carried out. Those four types are the linear velocity feedback control, the cubic velocity feedback control, the non-linear saturation controller (NSC) and the positive position feedback (PPF) controller. The suitable type is the PPF controller for suppression the vibrations of the cantilever beam. The approximate solution obtained up to the first approximation by using the multiple scale method. The PPF controller effectiveness is studied on the system. We used frequency-response More >

Ravindra Birajdar^1,*, Appasaheb Keste², Shravan Gawande²

Sound & Vibration, Vol.55, No.4, pp. 305-327, 2021, DOI:10.32604/sv.2021.017000 - 18 October 2021

Abstract The objective of the study is to find the tolerance on vane pitch dimensions of a Vertical Turbine (VT) pump impeller. For this purpose, the study is divided into two parts viz. to find the critical hydraulic eccentricity of a VT pump impeller by way of numerical simulations and design of experiments to find the vane pitch tolerance using critical hydraulic eccentricity. The effect of impeller vane pitch deviations on hydraulic unbalance is examined for a vertical turbine pump using Design of Experiments (DOE). A suitable orthogonal matrix has been selected with vane pitch at More >

S. Narayan^1,*, M. U. Kaisan², Shitu Abubakar², Faisal O. Mahroogi³, Vipul Gupta⁴

Sound & Vibration, Vol.55, No.3, pp. 221-234, 2021, DOI:10.32604/sv.2021.016539 - 15 July 2021

Abstract The health monitoring has been studied to ensure integrity of design of engine structure by detection, quantification, and prediction of damages. Early detection of faults may allow the downtime of maintenance to be rescheduled, thus preventing sudden shutdown of machines. In cylinder pressure developed, vibrations and noise emissions data provide a rich source of information about condition of engines. Monitoring of vibrations and noise emissions are novel non-intrusive methodologies for which positioning of various transducers are important issue. The presented work shows applicability of these diagnosis methodologies adopted in case of diesel engines. The effects More >

Jianqiang Xiong^*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.3, pp. 555-567, 2021, DOI:10.32604/fdmp.2021.015429 - 29 April 2021

Abstract A robust optimization design method is proposed to investigate the influence of the hook position on the vertical vibration (bending) of an automobile exhaust system. A block diagram for the robustness analysis of the exhaust system is initially constructed from the major affecting factors. Secondly, the second-order inertia force is set as the vibration excitation source of the exhaust system and the displacement of four hooks of the exhaust system is selected as the variable factor. Then tests are carried out to investigate the resulting vertical bending considering four influencing factors and three levels of More >

Jaafar Hallal^1,*, Mahmoud Fakih², Hala Damerji³, Mohammad Hammoud^4,5, Mehdi Chouman^4,5

Sound & Vibration, Vol.55, No.2, pp. 131-140, 2021, DOI:10.32604/sv.2021.015293 - 21 April 2021

Abstract Vibration can be introduced in all mechanical fields in our life. Engineers try to avoid its negative effect leading in some cases to deformation in the machines. Many researches are dedicated to study the identification of damping especially in multi degree of freedom systems with particular attention to the source of energy dissipation. They focus on developing new tools or methods which may be used in real problems to obtain accurate results about the amount (or value) and the location of energy dissipation in the structure. The aim of this paper is to present an… More >

Ehsan Noroozinejad Farsangi^1,*, Aleksandra Bogdanovic², Zoran Rakicevic², Angela Poposka², Marta Stojmanovska²

Structural Durability & Health Monitoring, Vol.14, No.4, pp. 283-301, 2020, DOI:10.32604/sdhm.2020.010564 - 04 December 2020

Abstract In this study, the methodology and results of ambient vibration-based investigations of the historical Tash Mosque in Kosovo and a 3-story historical building in Bulgaria are presented. The investigations include full-scale in situ testing of both structures due to ambient vibrations induced by micro-seismic, wind, traffic, and other human activities. To this aim, Ranger seismometers and Kinemetric products were used. Measurements were performed in both horizontal directions in several points along the structures’ height utilizing a high-speed data acquisition device. All recorded data have been analyzed and processed by the software developed at IZIIS, and More >

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 - 25 November 2020

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… 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 - 31 August 2020

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 >