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  • Open Access


    Investigation of the Free Vibrations of Radial Functionally Graded Circular Cylindrical Beams Based on Differential Quadrature Method

    Xiaojun Huang1,2, Liaojun Zhang1,*, Renyu Ge2, Hanbo Cui2, Zhedong Xu2

    CMES-Computer Modeling in Engineering & Sciences, Vol.132, No.1, pp. 23-41, 2022, DOI:10.32604/cmes.2022.019765

    Abstract In the current research, an effective differential quadrature method (DQM) has been developed to solve natural frequency and vibration modal functions of circular section beams along radial functional gradient. Based on the high-order theory of transverse vibration of circular cross-section beams, lateral displacement equation was reconstructed neglecting circumferential shear stress. Two equations coupled with deflection and rotation angles were derived based on elastic mechanics theory and further simplified into a constant coefficient differential equation with natural frequency as eigenvalue. Then, differential quadrature method was applied to transform the eigenvalue problem of the derived differential equation into a set of algebraic… More >

  • Open Access


    An Improved Model to Characterize Drill-String Vibrations in Rotary Drilling Applications

    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

    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 model equations. The results show… More >

  • Open Access


    Dimensional Amplitude Response Analysis of Vibrations Produced by Defects in Rolling Contact Bearings

    Imran M. Jamadar1,*, 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

    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 dimensional analysis using frequency domain… More >

  • Open Access


    A Suitable Active Control for Suppression the Vibrations of a Cantilever Beam

    Y. A. Amer1, A. T. EL-Sayed2, M. N. Abd EL-Salam3,*

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

    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 equations to investigate the stability… More >

  • Open Access


    Vibration Control of Vertical Turbine Pump by Optimization of Vane Pitch Tolerances of an Impeller Using Statistical Techniques

    Ravindra Birajdar1,*, Appasaheb Keste2, Shravan Gawande2

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

    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 different axial locations of an… More >

  • Open Access


    Optimization of Transducer Location for Novel Non-Intrusive Methodologies of Diagnosis in Diesel Engines

    S. Narayan1,*, 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

    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 of changing various fuel injection… More >

  • Open Access


    Influence of the Hook Position on the Vertical Vibrations of an Automobile Exhaust System: Application of the Robust Optimization Design

    Jianqiang Xiong*

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

    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 analysis. Finally, a variance analysis… More >

  • Open Access


    Experimental Modal Damping Identification of a Mechanical Structure Using Video Magnification Technique

    Jaafar Hallal1,*, Mahmoud Fakih2, Hala Damerji3, Mohammad Hammoud4,5, Mehdi Chouman4,5

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

    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 original procedure aims to experimentally… More >

  • Open Access


    Ambient Vibration Testings and Field Investigations of Two Historical Buildings in Europe

    Ehsan Noroozinejad Farsangi1,*, 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

    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 then the processed data were… More >

  • Open Access


    Cost Optimized Non-Contacting Experimental Modal Analysis Using a Smartphone

    Jaafar Hallal1,2,3,*, Mohammad Hammoud2,3, Mahmoud Fakih2,3,4, Ali Hallal2,3

    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 >

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