Yusry O. El-Dib, Nasser S. Elgazery^*

Sound & Vibration, Vol.56, No.1, pp. 21-36, 2022, DOI:10.32604/sv.2022.014166

Abstract In this article, the main objective is to employ the homotopy perturbation method (HPM) as an alternative to classical perturbation methods for solving nonlinear equations having periodic coefficients. As a simple example, the nonlinear damping Mathieu equation has been investigated. In this investigation, two nonlinear solvability conditions are imposed. One of them was imposed in the first-order homotopy perturbation and used to study the stability behavior at resonance and non-resonance cases. The next level of the perturbation approaches another solvability condition and is applied to obtain the unknowns become clear in the solution for the first-order solvability condition. The approach… More >

R. Adithya Pillai¹, S. Sakthivel Murugan^2,*, Guruprasad Gupta¹

Sound & Vibration, Vol.56, No.1, pp. 51-64, 2022, DOI:10.32604/sv.2022.012085

Abstract In any closed environment considered, it can be seen that the acoustic parameters are inherently not constant over the entire area considered. In a closed environment, it is ideally preferred to maintain the acoustic parameters as constant so that there exists better quality of sound leading to better auditory perception with respect to the audience. Practically, some of the acoustic parameters like reverberation time and clarity do not strictly pertain to the pattern obtained theoretically. In this paper, simulations are carried out using I-SIMPA under different values of Sound Transmission Class (STC), source position, distribution and the chamber dimensions and… More >

Ravindra Birajdar^1,*, 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 >

Ali Askari¹, Ali Salehi Sahl Abadi^2,*, Alimardan Alinia³, Milad Pourjaafar⁴, Aref Honairi Haghighi⁵, Elham Akhlaghi Pirposhteh⁶

Sound & Vibration, Vol.55, No.4, pp. 329-341, 2021, DOI:10.32604/sv.2021.016662

Abstract Among the harmful occupational factors, noise is the most common exposure in the oil industrial workplaces. The present study aimed to prioritize sound pollution areas in central processing facilities (CPF) of an oil field in order to provide corrective action in the studied industry and similar industries. After reviewing the issued permit to work, job description and noise dosimetry test, the evaluated areas were selected then sound pressure levels in the referenced areas investigated according to ISO 9612–2009 (E) next the noise map prepared for all selected areas. For identifying the prioritized areas to implement the control measures NCPI was… More >

Olkan Çuvalcı¹, Faruk Ünker^2,*, Turgut Batuhan Baturalp³, Utku Gülbulak³, Atila Ertaş³

Sound & Vibration, Vol.55, No.4, pp. 281-294, 2021, DOI:10.32604/sv.2021.015705

Abstract In this paper, an experimental model of a horizontal cantilever beam with a rotating/oscillating attached to the shaker for harmonic excitation at the one end and a gyrostabilizer at the other end is built to verify the equations of the Lagrangian model. The primary focus of the study was to investigate the parameters of excitation amplitude, natural frequency, rotating mass (disk mass), and disk speed of gyro that would minimize the amplitude of the beam to identify these effects. Numerical and experimental results indicate that the angular momentum of the gyrostabilizer is the most effective parameter in the reduction of… More >

A. A. Soliman¹, K. R. Raslan², A. M. Abdallah^3,*

Sound & Vibration, Vol.55, No.4, pp. 263-279, 2021, DOI:10.32604/sv.2021.015014

Abstract The fundamental objective of this work is to construct a comparative study of some modified methods with Sumudu transform on fractional delay integro-differential equation. The existed solution of the equation is very accurately computed. The aforesaid methods are presented with an illustrative example. More >

Vignesh Sekar^1,*, Se Yong Eh Noum¹, Azma Putra², Sivakumar Sivanesan¹, Kok Chun Chin¹, Yi San Wong¹, Dg Hafizah Kassim³

Sound & Vibration, Vol.55, No.4, pp. 343-352, 2021, DOI:10.32604/sv.2021.014916

Abstract This paper presents the development and performance of micro-perforated panels (MPP) from natural fiber reinforced composites. The MPP is made of Polylactic Acid (PLA) reinforced with Oil Palm Empty Fruit Bunch Fiber (OPEFBF). The investigation was made by varying the fiber density, air gap, and perforation ratio to observe the effect on the Sound Absorption Coefficient (SAC) through the experiment in an impedance tube. It is found that the peak level of SAC is not affected, but the peak frequency shifts to lower frequency when the fiber density is increased. This phenomenon might be due to the presence of porosity… More >

Yanni Zhang^1,2, Jing Pang^1,2,*

Sound & Vibration, Vol.55, No.4, pp. 295-303, 2021, DOI:10.32604/sv.2021.014445

Abstract In this article, time fractional Fornberg-Whitham equation of He’s fractional derivative is studied. To transform the fractional model into its equivalent differential equation, the fractional complex transform is used and He’s homotopy perturbation method is implemented to get the approximate analytical solutions of the fractional-order problems. The graphs are plotted to analysis the fractional-order mathematical modeling. 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

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 >

Al Munawir¹, Azma Putra^2,*, Iwan Prasetiyo³, Wan Mohd Farid Wan Mohamad², Safarudin Herawan⁴

Sound & Vibration, Vol.55, No.3, pp. 203-219, 2021, DOI:10.32604/sv.2021.015938

Abstract Statistical Energy Analysis (SEA) is a well-known method to analyze the flow of acoustic and vibration energy in a complex structure. This study investigates the application of the corrected SEA model in a non-reverberant acoustic space where the direct field component from the sound source dominates the total sound field rather than a diffuse field in a reverberant space which the classical SEA model assumption is based on. A corrected SEA model is proposed where the direct field component in the energy is removed and the power injected in the subsystem considers only the remaining power after the loss at… More >