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The purpose of this study is to investigate the effects of nanoadditive lubricants on the vibration and noise characteristics of helical gears compared with conventional lubricants. The experiment aims to analyze whether nanoadditive lubricants can effectively reduce gear vibration and noise under different speeds and loads. It also analyzes the sensitivity of the vibration reduction to load and speed changes. In addition, it compares the axial and radial vibration reduction effects. The goal is to explore the application of nanolubricants for vibration damping and noise reduction in gear transmissions. The results provide a basis for further research on nanolubricant effects under high-speed conditions.

Helical gears of 20CrMnTi were lubricated with conventional oil and nanoadditive oils. An open helical gearbox with spray lubrication was tested under different speeds (200–500 rpm) and loads (20–100 N·m). Gear noise was measured by a sound level meter. Axial and radial vibrations were detected using an M+P VibRunner system and fast Fourier transform analysis. Vibration spectrums under conventional and nanolubrication were compared. Gear tooth surfaces were observed after testing. The experiment aimed to analyze the noise and vibration reduction effects of nanoadditive lubricants on helical gears and the sensitivity to load and speed.

The key findings are that nanoadditive lubricants significantly reduce the axial and radial vibrations of helical gears under low-speed conditions compared with conventional lubricants, with a more pronounced effect on axial vibrations. The vibration reduction is more sensitive to rotational speed than load. At the same load and speed, nanolubrication reduces noise by 2%–5% versus conventional lubrication. Nanoparticles change the friction from sliding to rolling and compensate for meshing errors, leading to smoother vibrations. The nanolubricants alter the gear tooth surfaces and optimize the microtopography. The results provide a basis for exploring nanolubricant effects under high speeds.

The originality and value of this work is the experimental analysis of the effects of nanoadditive lubricants on the vibration and noise characteristics of hard tooth surface helical gears, which has rarely been studied before. The comparative results under different speeds and loads provide new insights into the vibration damping capabilities of nanolubricants in gear transmissions. The findings reveal the higher sensitivity to rotational speed versus load and the differences in axial and radial vibration reduction. The exploration of nanolubricant effects on gear tribological performance and surface interactions provides a valuable reference for further research, especially under higher speed conditions closer to real applications.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2023-0220/

Wind power is the one of best natural resources to meet the demands of electricity in India. In this regard, one of engineering college in Visakhapatnam has procured wind turbine generators of 200 kWp and got these installed on the rooftop of the college buildings for research and power generation. After starting the mills, huge vibrations were experienced by the staff and students in the laboratories and classrooms. So, the purpose of this paper is to carry out vibration and noise studies on wind turbine generator to identify the problem for high vibrations and suggest a novel method for vibration reduction.

Experimental vibration and natural frequency investigations are carried when wind velocity around 6.0 m/s using frequency analyzer, impact hammer, condenser microphone and accelerometer. An attempt is made to reduce the vibration and noise level of wind turbine generator by inserting a steel coil spring of 300 mm length having 20 turns in series with turnbuckle D shackle assembly, which is used to connect the wind turbine generator to the hook mounted on slab.

A high vibration velocity of 9.9 mm/s was observed on at base frame of wind turbine generator. The natural frequencies of hook and slab are observed in between 15 to 20 Hz from the natural frequency test. A high noise of 94.67 dBA is observed at a distance of 1 m from the base of wind turbine generator along the rotational axis of rotor. After modification to the baseline, WTG the vibration and noise levels are reduced to 4.8 mm/sec and 77.76 dBA, respectively.

This is the first time to study the huge vibrations generated in wind turbine generators installed on the rooftop of the college. Developed a novel methodology to reduce the vibrations by inserting a steel coil springs in turnbuckle D shackle assembly of wind turbine generators. After modification, wind turbine generator are running successfully without any high vibrations.

Reducing noise and vibration is an increasingly important objective for designers and users of a wide range of mechanical systems. Lubricants can contribute to reduction of overall noise and vibration generated by machines, both by reducing generation of acoustic energy in lubricated contacts and by modulating the transmission of vibration through the lubricant. This paper outlines various mechanisms by which the lubricant may affect the generation and transmission of acoustic vibration. Examples from the area of refrigeration compressor lubrication are presented, demonstrating that correct design and selection of lubricant can have a significant impact on noise and vibration.

Investigates the hazard to health caused by noise and vibration, suggesting that these two health hazards have long been seen as the Cinderella to many other health and safety issues. However, there still exists a degree of ignorance over the risk of lower levels of noise or vibration; senior managers see only the cost of solving these problems rather than the danger. Provides a history of noise and vibration legislation; provides a key for a noise reduction programme. Continues to suggest ways to identify noise and vibration exposure.

The public’s awareness of noise and vibration forms a significant barrier to further development of railways. This chapter begins with a short introduction to the main fundamental aspects of acoustics, including decibels, frequency analysis, the propagation of sound with distance and common measurement quantities. The main sources of railway noise are discussed, including rolling noise, impact noise, curve squeal and aerodynamic noise. Simple calculation procedures are described that can be used to assess the impact of railway noise and to compare it with legal limits. The final section is devoted to ground vibration, which is a related form of environmental disturbance.

Electromagnetic noise of permanent magnet synchronous motor (PMSM) seriously affects the sound quality of electric vehicles (EVs). This paper aims to present a comprehensive process for the electromagnetic noise analysis and optimization of a water-cooled PMSM.

First, the noises of an eight-pole 48-slot PMSM in at speeds up to 10,000 rpm are measured. Furthermore, an electromagnetic-structural-acoustic model of the PMSM is established for multi-field coupling simulations of electromagnetic noises. Finally, the electromagnetic noise of the PMSM is optimized by using the multi-objective genetic algorithm, where a multi-objective function related to the slot width of PMSM stator is defined for radial electromagnetic force (REF) optimization.

The experimental results show that main electromagnetic noises are the 8n-order (n = 1, 2, 3, …) and 12-order noises. The simulated results show that the REFs are mainly generated by the 8n-order (n = 1, 2, 3, 4, 5, 6) vibrations, especially those of the 8th, 16th, 24th and 32th orders. The 12-order noise is a mechanical noise, which might be caused by the bearings and other structures of the PMSM. Comparing the simulated results before and after optimization, both the REFs and electromagnetic noises are effectively reduced, which suggests that an appropriate design of stator slot is important for reducing electromagnetic noise of the PMSM.

In view of applications, the methods proposed in this paper can be applied to other types of PMSM for generation mechanism analysis of electromagnetic noise, optimal design of PMSM and thereby noise improvement of EVs.

Thermal power plants have many problems regarding noise and vibration. Previous studies have shown that such problems are often related to the fans. However, the internal flows are difficult to analyze to find the cause of vibration and noise in fans in actual tests. Therefore, the unsteady internal flow field in a centrifugal fan was simulated numerical to identify the source. This paper aims to present these issues.

The unsteady Reynolds‐averaged Navier‐Stokes equations with the SST k‐ω turbulence model were solved to simulate the flow within the entire flow path of the fan. The conservation of mass and moment and energy equations were used to solve the flow field distribution. The time‐dependent pressure pulsations on the impeller were analyzed for the dynamics problem. The finite volume method with the SIMPLEC algorithm was used to discretize the time‐dependent equations. The second‐order upwind scheme was used for the convection terms and the central difference scheme was chosen for the diffusion terms in the momentum and transport equations.

The numerical simulations illustrated the flow characteristics inside the double suction centrifugal fan. The predicted efficiency is almost the same as the experimental value. The estimated pressure and temperature fields are quite reasonable. The results showed that the interaction between the non‐uniform impeller flow and the fixed volute aroused the significant pressure fluctuations, which is an important source of vibration and noise in centrifugal machinery.

It is assumed that there is no change in the density in the whole flow passage, and the predicted outlet temperature is about 1.15 per cent lower than the experimental result.

The simulation study indicates that the prediction of noise is possible by using pressure pulsation. It is recommended to control the pressure pulsation in the fans, to decrease the vibration and noise of thermal power plants.

This paper aims to design a tip state estimation method for a hybrid-structured flexible manipulator (HSFM) with one rotating joint and one telescopic joint in the vertical plane.

The HSFM model is decomposed into a static deflection model and a vibration model. The sliding discrete Fourier transform (SDFT) is used to filter the high frequency noise and obtain main vibration components to represent the vibration model. Then, a novel fuzzy logic adaptive Kalman filter (FLAKF) is designed to estimate the state of a vibrational equilibrium position. The complete tip state of the HSFM is obtained by superimposing the FLAKF filter results with the SDFT vibration analysis results.

Both the simulation results and physical experimental results verify the effectiveness of the proposed tip state estimation method. The vibration analysis based on SDFT is used to represent the vibration model and reduce the computational complexity in the process of solving differential equation. The proposed FLAKF can effectively increase the stability and robustness of the estimator.

In this paper, the tip state estimation problem of the HSFM in vertical plane is first proposed. The effect of gravity on the HSFM is considered by the static deflection model. A precise tip state estimator is designed by a closed loop SDFT and a novel FLAKF, which can provide an accurate feedback for the vibration control controller and make an accurate evaluation of the control effect.

This paper aims to investigate the friction noise properties of M50 matrix curved microporous channel composites filled with solid lubricant Sn-Ag-Cu (MS).

Pure M50 (MA) and MS are prepared by selective laser melting and vacuum-pressure infiltration technology. The tribological and friction noise properties of MA and MS are tested through dry sliding friction and then the influential mechanism of surface wear sate on friction noise is investigated by analyzing the variation law of noise signals and the worn surface characteristics of MS.

Experimental results show that the friction noise sound pressure level of MS is only 75.6 dB, and it mainly consists of low-frequency noise. The Sn-Ag-Cu improves the surface wear state, which reduces self-excited vibration of the interface caused by fluctuation of friction force, leading to the decrease of friction noise.

This investigation is meaningful to improve the tribological property and suppress the friction noise of M50 bearing steel.

The purpose of this paper is to present the original study of an industrial device. Industrial inductors are used to decrease the current variations, resulting from the use of modern power converters. To reduce these variations, the magnetic energy stored in these components is automatically used when the receptor is unconnected to the principal sources. Such storage is generally obtained by using a magnetic circuit containing air‐gaps. The rigidity of this circuit, associated with the magnetic stresses which appear in these areas, causes the structure to produce mechanical vibration and to emit audible sounds.

Experiments, simulations and test devices are used to determine the main physical phenomenon that generates the undesirable audible noise. The resulting knowledge is used to design a quieter device.

The mechanical vibrations and emitted noises are attached to magnetic effects. Even if it is not possible to suppress all these effects, the level of sound emitted can be decreased through a suitable design of the magnetic core.

Industrial inductors are usually built and designed using methods coming from the transformer studies. A new concept for the design of the magnetic core is presented. Experimental approaches and numerical simulations are performed in order to highlight the physical behaviours of the coils and their magnetic coupling to the magnetic core. It appears that breaking the magnetic core into free parts is an original solution that decreases the emitted noise.