Vol. 60 No. 5 (2026)

Open Access

Article

Article ID: 4406

The Effect of music genre on work productivity in repetitive tasks: An experimental study for sound and vibration applications

by Heri Setiawan, Pawenary, Micheline Rinamurti, Sani Susanto

Sound & Vibration, Vol.60, No.5, 2026;

The physical work environment significantly influences worker performance, with workplace acoustics playing an important role in cognitive functioning and productivity. This study investigated the effect of music genre as an engineered acoustic intervention on productivity during repetitive industrial tasks. Unlike previous studies emphasizing psychological outcomes, this research integrates occupational acoustics, industrial ergonomics, and productivity engineering to evaluate music as a controllable workplace sound variable. A repeated-measures experimental design was conducted under four auditory conditions: no music, jazz, pop, and instrumental music. Productivity was assessed using output and work cycle time during repetitive manual tasks. Data were analyzed using one-way repeated-measures analysis of variance (RM-ANOVA) followed by Bonferroni-adjusted pairwise comparisons. Mauchly's test confirmed that the sphericity assumption was satisfied (W = 0.964, p = 0.119). Music genre had a significant effect on productivity (F(3,897) = 412.68, p < 0.001, partial η² = 0.58). Pop music produced the greatest productivity improvement (33.82%), followed by jazz (13.03%) and instrumental music (10.45%). Bonferroni comparisons showed that pop music significantly outperformed all other auditory conditions, whereas instrumental music did not differ significantly from the control condition. These findings demonstrate that appropriately designed auditory environments can enhance productivity during repetitive work. The study contributes to occupational acoustics by positioning music as an engineered environmental variable that supports human-centered industrial design and operational performance.

Open Access

Article

Article ID: 2029

Influence of parameter changes on honeycomb structure debonding detection based on band gap method

by Ye Yuan, Bin Liu, Chengyou Lei, Zhiguo Zhang

Sound & Vibration, Vol.60, No.5, 2026;

Honeycomb structures have been widely used in many industrial fields due to their excellent properties. However, it is always challenging to rapidly and accurately detect defects such as debonding in the structure, especially in the in-service situation. In response to this, we have proposed an acoustic testing method without coupling agents based on the acoustic band gap feature in the structure. However, the influence of test parameters such as signal excitation and reception on the band gap feature has not been comprehensively and thoroughly investigated, and the parameters have not been optimized. In this paper, the transmission frequency response (TFR) curves were measured, and the band gap features were investigated at different parameters. The results demonstrated that the band gap feature changes a little with the pressure between the probes and the specimen, the amplitude of the exciting signal, the sweep duration, and the detection direction. While it changes significantly with the exciting-receiving distance. Experimental results demonstrated that to form a stable band gap feature, the wave should propagate through at least three honeycomb unit widths before being received. Further analysis indicates that the defect resolution of the proposed method is about two honeycomb unit widths. This work can be used to select the proper detection parameters and further improve the reliability and efficiency of this technique.

Open Access

Article

Article ID: 4413

A practical approach for improving the robustness of MVDR beamformers

by Nguyen Thi Huyen Chau, Quan Trong The, Pham Van Ha

Sound & Vibration, Vol.60, No.5, 2026;

Microphone array (MA) owns the convenience of alleviating the background noise field, interference, and third-party speakers while preserving the original speech component with a high directivity index perspective. MA beamforming utilizes prior spatial information about the direction of arrival of useful signals, the characteristics of the surrounding noise field, the designed geometry of MA, and the obtained parameters after processing received array signals to achieve the advantages of speech enhancement and noise reduction. Minimum Variance Distortionless Response (MVDR) beamformer has the capability of attenuating the surrounding noise field, interference, or third-party talker while saving the original speech component of the desired talker at a specified location. However, under realistic recording scenarios, due to the complex and annoying situation, the movement of the talker during conversation, the error of internal settings for capturing the noisy mixture, the error of sampling frequency, the different time of starting recording of two microphones, the overall effectiveness of the MVDR beamformer is often degraded because of speech distortion and musical noise. In this article, the author proposed an efficient method for enhancing the robustness of the MVDR beamformer under complex and annoying situations. The numerical simulations have shown that the speech distortion was reduced to 5 dB, the musical and residual noise were suppressed to 15.2 dB, and the speech quality was increased from 12.1 to 12.9 dB.

Open Access

Article

Article ID: 4458

Meta-lens for acoustic concentration and enhanced sensing via transformation acoustics

by Botao Yang, Li Cai, KunSheng Xing, Shixin Yu, Huajie Hong

Sound & Vibration, Vol.60, No.5, 2026;

Detecting weak acoustic signals requires broadband energy concentration, but the acoustic power coupled into a device can be strongly curtailed by impedance mismatch at the inlet. Here, we develop a transformation-acoustics-based acoustic meta-lens in which a rectangular virtual domain is mapped to a trapezoidal physical domain, directing incident energy toward a narrow output aperture. In contrast to an air-filled trapezoidal horn with the same outer envelope, the meta-lens reshapes the wavefront through a spatially varying anisotropic mass-density tensor and an equivalent bulk modulus. A cubic-polynomial transition layer is introduced at the inlet to bridge the parameter jump between air and the anisotropic equivalent medium. Finite-element simulations from 200 to 3,000 Hz show positive sound transmission gain for the original design, with a mean value of 3.582 dB. With the transition layer, the mean gain increases to 5.470 dB, the minimum gain rises from 2.695 dB to 3.672 dB, and the mean inlet reflection coefficient decreases from 0.5644 to 0.3239, corresponding to a reduction of 42.6%. A genetic algorithm optimization of the lens length, inlet width, outlet width, and transition-layer thickness further increases the maximum gain from approximately 6.54 dB to 7.36 dB and the minimum gain from approximately 3.67 dB to 4.14 dB. These results indicate that inlet impedance grading and geometric optimization can work together to provide more robust broadband acoustic concentration for weak-signal sensing.

Open Access

Article

Article ID: 4407

Acoustic characterization and modeling of padel courts in urban residential environments

by Aracelly Núñez-Naranjo, Jose Gabriel Vasquez, Paulina Ayala, Marcelo V. Garcia

Sound & Vibration, Vol.60, No.5, 2026;

Padel courts are now common in many residential and mixed-use projects, but the published measurement base for their outdoor noise impact is still small. Recent work has flagged siting conflicts and padel-related acoustic concerns, yet few studies place padel and tennis side by side under the same site conditions. This paper addresses that gap through field measurements and acoustic modeling at one mixed-use development in Abu Dhabi, United Arab Emirates. A padel court and a tennis court were each recorded for a single 15-minute period, and the resulting levels fed an outdoor propagation model. At 10 m, the padel court reached LAeq = 64.2 dB(A) and LAmax = 71.3 dB(A), against LAeq = 58.4 dB(A) and LAmax = 63.6 dB(A) for tennis. Padel showed stronger octave-band content at mid- and high frequencies, consistent with ball-wall impacts and reflections off its rigid glass and metal enclosure. These levels were then carried into a CadnaA model built on ISO 9613-2 to trace propagation toward the nearest residential facades. With 4 m barriers around the padel courts, predicted facade levels at the most shielded positions fell by 4 to 5 dB(A). A single site and one recording per sport bound these conclusions: they describe a case study rather than a general emission standard for padel. What the data do provide is a matched padel-versus-tennis comparison and a worked example of how a small field set can steer acoustic planning early in residential design.

Open Access

Article

Article ID: 4224

Weak fault feature extraction and system fault analysis under strong noise

by Tiejun Cui, Zijian Cui, Shasha Li

Sound & Vibration, Vol.60, No.5, 2026;

To tackle the intractable problems including weak fault feature extraction and evolution uncertainty quantification for complex systems in strong noise environments, a novel method for weak fault diagnosis and evolution analysis is proposed. This method integrates the fuzzy structured element (FSE), cloud model (CM), and Space Fault Network (SFN). The method centers on adaptive wavelet denoising, fault feature cloudification, and SFN probability propagation. The fault signal under strong noise is reconstructed by optimizing the wavelet threshold with the FSE. The uncertainty encapsulation of the peak factor of fault features is realized based on the CM to establish the feature CM. The fault event topology is constructed relying on the SFN. The quantitative transfer of uncertainty in the fault evolution is achieved combined with cloud algebra. Verified by the inner ring pitting fault of axle box bearings, the results demonstrate that the proposed method can extract the fault characteristic frequency of 250.5 Hz. The derived fault probability CM (0.680, 0.059, 0.023) accurately quantifies the system risk level. This result is consistent with the actual fault evolution law in engineering practice. This method provides technical support for early fault warning and maintenance of complex industrial system. Furthermore, comparative experiments confirm its superiority over traditional methods in noise suppression and feature retention. Parameter analysis is also discussed to improve engineering generalization.

(This article belongs to the Special Issue Vibration and System Fault Analysis)

Open Access

Article

Article ID: 4180

Audio signal approximation and fuzzy logic-based acoustic noise-risk assessment using Fourier–Dirichlet analysis and hyperbolic series representations

by Yogeesh Nijalingappa, Asokan Vasudevan, Soon Eu Hui, Zetty Pakir Mastan, Choo Wou Onn, Mohammed Almakki

Sound & Vibration, Vol.60, No.5, 2026;

This paper presents an acoustics-oriented study that combines classical Fourier–Dirichlet signal approximation with a fuzzy logic-based noise-risk interpretation layer. The harmonic-analysis part revisits Fourier series for periodic and quasi-periodic audio waveforms under classical Dirichlet conditions and restates these conditions in a form that is practically checkable on sampled audio segments; no new convergence theorem is claimed. A complementary hyperbolic-series representation is used as an illustrative analytical tool for discussing compact representations of selected waveform classes. The applied contribution of the paper is a Mamdani fuzzy inference system that converts uncertain acoustic measurements into an interpretable Noise-Risk Index using A-weighted equivalent sound level, daily exposure duration, and source–receiver distance. The fuzzy model uses triangular/trapezoidal memberships, an interpretable rule base, min–max inference, and centroid defuzzification. To show the practical usefulness in sound and vibration practice, one waveform-reconstruction example and a twelve-scenario acoustic-risk dataset with regard to traffic, workshop, generator room, and public address contexts are reported in the study. The resulting fuzzy system generates a range of risk scores from 22 to 92, lying within the safe, caution, high, and critical level categories and depicts smooth transitions as we approach decision boundaries where a crisp threshold can often be challenging to decode. This work thus establishes Fourier analysis as the underlying level for acoustic signals and fuzzy inference as a decision-support level in the context of uncertainty-based exposure assessment. The current coupling is linear instead of feature-driven: the Fourier-based signal description forms the basis for exposure descriptors, and the fuzzy system processes these descriptors given uncertainty.

Open Access

Article

Article ID: 4463

Thermoacoustic loss-of-chaos in large diesel engines: Case study on long-timescale events

by Alice Elizabeth González, Pablo Gianoli-Kovar, Héctor Campello-Vicente

Sound & Vibration, Vol.60, No.5, 2026;

This work aims to analyze the occurrence of anomalous acoustic emissions that appeared after the modification of the combustion chambers of eight reconverted four-stroke diesel engines (10 MW each, urban installation). Large variability of the sound pressure levels emitted by the same engine under nominally identical operating conditions was recorded. The phenomenon was interpreted at first as thermoacoustic instability developing inside the combustion chambers, supported by the simultaneous observation of large fluctuations in the fuel inlet pressure. Four precursor episodes were documented through an operational signature qualitatively consistent with the loss-of-chaos pattern reported in the literature. However, most of these events anticipated a decrease in the sound pressure levels in the considered third-octave band, the opposite of what is expected to happen in thermoacoustic instability events. The 0–1 test for loss-of-chaos was applied, ratifying the occurrence of a long precursor condition that should anticipate the installation of a thermoacoustic instability. The shortest timescale of the precursor states was 500 s, in contrast with the millisecond- to second-range timescales typically reported in laboratory-scale studies. Although the sample is limited, the observations suggest that long precursors may occur in megawatt-scale installations, anticipating different types of sudden changes in the operational conditions (not only thermoacoustic instability). If confirmed, it would open a practical window for feedforward active noise control to avoid abrupt changes in the engine operating conditions. A hybrid silencing strategy is proposed as a design recommendation. Limitations and the current operational status of the installation are also discussed.

Open Access

Article

Article ID: 4497

Broadband vibration suppression of a nonlinear beam using a fractional-order inerter-assisted tuned mass damper

by Yogeesh  Nijalingappa, Suleiman Ibrahim  Mohammad, Tarun Madan  Kanade, Asokan  Vasudevan, P. William, Mohammad Faleh  Ahmmad Hunitie

Sound & Vibration, Vol.60, No.5, 2026;

This study presents an analytical method for reducing broadband vibration in a simply supported nonlinear beam fitted with an inerter-assisted tuned mass damper. The first bending mode is obtained by Galerkin projection, geometric nonlinearity is represented by a cubic stiffness term, and beam damping is described by a fractional-order derivative. A single-harmonic balance formulation converts the coupled equations into an amplitude-dependent cubic equation that is solved directly over the forcing-frequency range. The absorber is optimized with respect to inertance ratio, tuning ratio, damping ratio, and fractional order. The objective is to minimize the largest beam amplitude between 7 and 14 Hz. For the beam considered, increasing the inertance ratio from 0 to 0.20 raises the peak-response reduction from about 4.5% to about 52%, while the physical absorber mass ratio remains 0.04. The optimal tuning ratio decreases as inertance increases, whereas the required absorber damping generally increases. A ±5% stiffness study shows that the optimized designs remain effective under moderate uncertainty. The results also clarify how fractional damping modifies the balance between effective stiffness and dissipation, enabling the proposed maps to support robust initial absorber selection before detailed high-fidelity validation. The resulting design maps and regression equations provide useful preliminary settings for later finite-element or experimental verification.

Open Access

Article

Article ID: 4326

Study on the vibration transmission speed and damping characteristics of piano soundboard

by Jinyi Chen, Guanzheng Wan, Lan He, Jing Zhou, Haotian Cui, Zhenbo Liu

Sound & Vibration, Vol.60, No.5, 2026;

The piano soundboard converts string vibrations into radiated sound, affecting tonal quality. However, the propagation and energy dissipation of vibration waves along different grain directions remain insufficiently studied. To study vibration wave propagation and dissipation in piano soundboards of different composite processes, four quarter-size soundboards (moisture content 7%–9%) were selected: one tone-wood soundboard (T) and three laminated boards (L90 with vertical core, L55 with inclined core, L180 with horizontal core). Free boundary conditions were simulated via elastic rope suspension; time-domain responses were recorded at 16 kHz sampling (2,048 points). The angle α between the line connecting the two accelerometers and the core layer direction (for T, grain direction defined as 0°) was varied from 0° (parallel) to 90° (perpendicular) in 15° steps. Wave velocity and damping ratios were extracted using gradient and envelope fitting methods. The results showed: T exhibited the highest wave velocity from 0° to 90°, decreasing with angle (R² = 0.985), and a maximum anisotropy ratio of 4.59; L90 was angle-insensitive with weak correlation (R² = 0.735); L55 showed a trend similar to T (R² = 0.990); the wave velocity of L180 generally decreased but rebounded at 30°. Broadband damping ratios were 0.002–0.007, with T averaging 0.0040 (maximum 0.0058), L90 the lowest (average 0.0035, maximum 0.0049), L55 the highest (average 0.0051, maximum 0.0065), and L180 averaging 0.0038 (maximum 0.0062). Narrowband analysis showed that the damping ratios of all soundboards decreased exponentially with increasing frequency. The results guide piano soundboard vibration, material selection, and processing.

Open Access

Article

Article ID: 4449

LBM-IBM simulation of aeolian vibration of a stranded overhead conductor with resolved cross-sectional geometry

by Xiaoyu Luo, Yunfeng Zou, Ming Nie, Ganyu Wang, Yongchun Liang, Zejia Yang

Sound & Vibration, Vol.60, No.5, 2026;

The outer surface of overhead transmission conductors is formed by wound aluminium strands, exhibiting a corrugated geometric profile. However, aerodynamic analyses typically simplify this geometry to a smooth cylinder. How this simplification influences the fluid-structure coupled vortex-induced vibration response remains unclear. This paper addresses this research gap through comparative numerical simulations between a geometrically refined stranded conductor and an equivalent smooth cylinder with identical outer diameter. A two-dimensional lattice Boltzmann–immersed boundary method (LBM-IBM) computational framework was developed on a fixed Cartesian grid and coupled with a Newmark-β transverse oscillator. Reduced-velocity sweeps and supplementary high-resolution flow-field cases were conducted under fully matched structural and fluid parameters. Results show that the smooth cylinder exhibits a narrow classical lock-in region with rapid amplitude decay beyond the peak. In contrast, the stranded conductor sustains large-amplitude vibrations over a considerably wider velocity range, accompanied by a substantial increase in time-averaged drag. Vorticity and phase analyses indicate that strand grooves function as local flow separation promoters, altering the lift-velocity phase relationship and maintaining positive aerodynamic energy input beyond the desynchronization boundary of the smooth cylinder. The findings confirm that strand-scale surface features significantly broaden the lock-in range, a conclusion that merits incorporation into high-fidelity aerodynamic models to improve conductor response prediction accuracy.

Open Access

Article

Article ID: 4498

Closed-form topological and spectral invariants for periodic ladder-based vibration networks

by Suleiman Ibrahim Mohammad, Yogeesh Nijalingappa, Asokan Vasudevan, P. William, Jonathan Lee, Tarun Madan Kanade , Mohammad Faleh Ahmmad Hunitie

Sound & Vibration, Vol.60, No.5, 2026;

This paper investigates two closely related network families, the open ladder graph and the cylindrical ladder graph, as exact test beds for degree-based, eccentricity-based, distance-based, and spectral descriptors. The two graphs can be seen as graph-theoretic two-rail models with and without periodic closure, allowing an exact comparison boundary effects versus cyclic-closure-effect. We obtain closed expressions for the Sombor index, reduced Sombor index, Sombor coindex, reduced Sombor coindex, first and second Zagreb indices, forgotten index, Randić index geometric-arithmetic index atom-bond connectivity index total eccentricity average eccentricity eccentric connectivity index Wiener Index radius diameter and total π-electron energy. For the energy part, we derive exact spectral sums and trigonometric closed forms using the Cartesian-product spectra of the underlying path and cycle graphs. Numerical tables and plots show that periodic closure increases all degree-regularity descriptors while sharply decreasing distance descriptors. In contrast, the total π-electron energy changes only by a small oscillatory amount, and both families share the same asymptotic energy density. The adjacency-based energy indeed can be interpreted explicitly as graph energy, instead of mechanical vibrational energy. An additional mass-spring formulation rooted on the graph Laplacian provides the analog equations of motion, natural-frequency spectra, dispersion samples and frequency-response operator for those analogous ladder topologies.

Open Access

Article

Article ID: 4490

Condition-based maintenance threshold determination for gearbox fault progression using vibration envelope features and accelerated life testing

by Asokan Vasudevan, Suleiman Mohammad, Mohammad Ahmmad Hunitie, Gui Jie, Jonathan Lee, Mbiatke Andrew

Sound & Vibration, Vol.60, No.5, 2026;

Gearbox failures represent a critical problem faced by industrial machines, considering the impacts of such failures on machine reliability, efficiency, and maintenance cost. Despite the well-established use of vibration-based condition monitoring techniques for diagnosing the presence of faults, few attempts have been made in transforming information about fault progression into thresholds that could be used in making condition-based maintenance (CBM) decisions. In this work, a CBM system for analysing gearbox fault progression based on vibration envelope features is presented, alongside accelerated life testing. An experimental approach has been adopted, whereby accelerated life testing was performed to induce gearbox degradation progressively. Then, vibration data were analysed through the envelope technique, out of which six vibration envelope features, namely RMS Envelope, Kurtosis, Crest Factor, Peak Amplitude, Envelope Energy, and Sideband Energy Ratio, were derived and analysed based on their sensitivity through correlation, monotonicity, trendability, and separability tests. Thereafter, a composite health index based on the most sensitive features was formulated, and a multilevel maintenance threshold system consisting of Alert, Warning, and Critical levels was created. The findings show that Envelope Energy, Sideband Energy Ratio, and Kurtosis have the highest sensitivity to degradation and can accurately represent the evolution of gearbox faults. The composite health index shows a strong correlation with the extent of degradation (R² = 0.962) and successfully discriminates between different health states of the gearbox. The developed framework for determining maintenance thresholds achieves an accuracy of 94.9%, which allows accurate identification of maintenance intervention phases.

Open Access

Article

Article ID: 4152

Simulation and algorithmic implementation of ultrasonic phased-array imaging for curved lead-seal surfaces

by Jian Cheng, Liguang Hu, Fengyin Zhang, Quan Zhang, Lianbing Wang

Sound & Vibration, Vol.60, No.5, 2026;

In ultrasonic phased-array sector scanning of lead-seal defects in high-voltage cable terminations, incomplete contact between the probe and the curved lead-seal surface may cause acoustic-beam spreading, focal shift, weak defect echoes, image distortion, and near-surface artefacts. To address these problems, this study proposes a curvature-adaptive ultrasonic phased-array imaging method for curved lead-seal surfaces. First, an acoustic-field simulation model of the curved lead-seal structure was established to analyze beam propagation through the couplant layer and the lead seal. Then, a delay law based on Fermat’s principle and Snell’s law was derived to account for the curved interface and the two-layer propagation path. The calculated delays were applied during post-processing delay-and-sum beam synthesis, followed by Hilbert-envelope extraction and angular coordinate correction. Numerical results show that the curved interface causes beam spreading and focal-position shift compared with a flat interface, which explains the localization deviation in conventional phased-array imaging. Laboratory experiments were further conducted on lead-seal specimens with internal defects, interlayer defects, and combined internal–interlayer defects. For the internal defect with an actual depth of 15.0 mm, the positioning error was reduced from 13.33% to 6.67%. For the interlayer defect with an actual depth of 25.0 mm, the positioning error was reduced from 10.00% to 4.00%. The results demonstrate that the proposed method improves defect localization accuracy, morphology restoration, and imaging consistency compared with conventional phased-array imaging. This study provides a simulation-supported and experimentally validated method for curved lead-seal ultrasonic imaging, although further validation is still required for naturally formed irregular cracks, variable coupling conditions, and field cable-terminal applications.

Open Access

Article

Article ID: 4460

Study of the dynamic vertical interaction of multi-axle rolling stock with railway track

by Asel Abdullayeva, Aidos Toktamyssov, Gabit Bakyt, Muslim Aikumbekov, Amandyk Yelshibekov, Ayaulym Abylkhanova

Sound & Vibration, Vol.60, No.5, 2026;

The continuous growth in the demand for increased capacity of the existing railway network of the Republic of Kazakhstan, particularly in regions bordering the Russian Federation and China, makes the issue of improving the operational safety of heavy-haul freight trains with increased mass and length especially relevant. The introduction of heavy trains represents a complex engineering and operational task that involves the use of more powerful locomotives, increased axle loads, reconstruction of track infrastructure and power supply systems, and the improvement of transportation technologies. In addition, higher train speeds combined with increasing freight traffic intensity require improvements in the strength and stability of the railway track structure. The technical policy of Kazakhstan Temir Zholy is aimed at a full transition to continuously welded track constructed on reinforced-concrete foundations. Edge stresses arising from rail bending and torsion under vertical and horizontal loads from rolling stock are among the key parameters determining rail strength. It is well known that the half-sum of the edge stresses characterizes the vertical impact on the track, whereas their half-difference represents the horizontal impact (lateral force). These parameters also reflect the influence of force moments generated by lateral loads and by the displacement of the conventional center of the wheel-rail contact patch relative to the rail head.

Open Access

Article

Article ID: 4418

Dynamic characteristics of a series-parallel-II inertial nonlinear energy sink for vibration control

by Ziying Wu, Rongxian Zhu, Yuanzhi Wang, Xi Guo, Jiyu Yan, Zizheng Wang

Sound & Vibration, Vol.60, No.5, 2026;

This paper proposes a novel series-parallel-II inertial nonlinear energy sink (SPII-I-NES) integrated with Coulomb friction. The governing equations of motion are formulated for the primary system coupled with the SPII-I-NES under both harmonic excitation and Gaussian white noise. By combining the harmonic balance method with the arc-length continuation method (ALM), quasi-analytical amplitude response solutions are derived for the primary structure and the SPII-I-NES under harmonic excitation. Numerical simulations demonstrate that the SPII-I-NES exhibits significantly superior vibration-suppression performance compared to the NES and linear series-parallel-II inerter configurations. Furthermore, the equivalent additional mass introduced by the SPII-I-NES is smaller than that of both the NES and the linear series-parallel-II inerter. The influence of key parameters on the dynamic responses of the primary system and SPII-I-NES is systematically investigated, including nonlinear stiffness coefficients, nonlinear damping ratios, and friction force. Results indicate that, compared to nonlinear damping ratios and friction forces, the nonlinear stiffness coefficients of the SPII-I-NES play a more dominant role in inducing strong nonlinear behaviors in both systems. Notably, when nonlinear Coulomb friction is considered, the primary system may exhibit quasi-periodic or chaotic vibration patterns. Under Gaussian white noise excitation, stochastic jumps or bifurcations are observed in both the primary system and the SPII-I-NES, highlighting the complex dynamic interactions introduced by this configuration.

Open Access

Article

Article ID: 4470

Nonlinear global dynamic characteristics and experimental validation of a cylindrical shell

by Haotian Song, Shufeng Lu

Sound & Vibration, Vol.60, No.5, 2026;

Based on first-order shear deformation theory and the Rayleigh-Ritz method, this paper establishes the dynamic model for a cylindrical shell with various boundary conditions (fixed, simply supported, free or elastically supported etc.) by means of Chebyshev polynomials and the artificial boundary spring method. To validate the proposed approach, a comparative study is first conducted with existing literature, finite element simulations, and experimental modal tests. The results demonstrate that the method can accurately predict the natural frequencies and mode shapes of the shell. Subsequently, the method of multiple scales is introduced to perform a perturbation analysis of the nonlinear governing equations. Through polar coordinate transformations, the four-dimensional averaged equations of the system are derived. Finally, based on the averaged equations, the amplitude–frequency response characteristics are systematically analyzed, revealing typical nonlinear phenomena such as multi-valued solutions, jump instabilities, and softening–hardening spring behaviors. Furthermore, the Runge–Kutta algorithm is employed to obtain the bifurcation diagrams, phase portraits, Poincaré maps, and maximum Lyapunov exponents. The results indicate that the external excitation amplitude acts as the dominant parameter inducing bifurcations and chaos, whereas the detuning parameter exhibits a weakly sensitive local perturbation effect.

Open Access

Article

Article ID: 4403

Modeling and simulation of hybrid electric propulsion systems for amphibious vehicle

by Van-Tong Em Nguyen, Van-Trang Nguyen, Tat-Hien Le, Cao-Thanh Nhi Ninh, Thai-Nguyen Vo

Sound & Vibration, Vol.60, No.5, 2026;

Amphibious vehicles operate across land and water, requiring stable environmental transitions. Although series hybrid electric propulsion systems (Series HEPS) offer flexible power distribution for these dual-environment demands, existing studies often limit dynamic analysis to individual environments. The transition phase, where buoyancy, hydrodynamic drag, and wheel loads vary simultaneously, lacks a unified mathematical framework. This study develops an integrated longitudinal dynamic model coupled with a Series HEPS, enabling continuous simulation across three phases: land, water, and transition. The land phase considers rolling resistance, aerodynamic drag, and wheel traction, whereas the water phase determines hydrodynamic resistance via the Holtrop-Mennen method and a propeller thrust model. Notably, for the transition phase, a proposed geometric relationship links longitudinal displacement along the bank slope to submergence depth, determining real-time buoyancy variations and wheel load redistribution. Simulation scenarios evaluate velocity, acceleration, and traction requirements across all phases, analyzing the influence of bank slope angles and ground friction on climbing capability. Simulation results demonstrate that the proposed HEPS configuration is highly reliable, achieving maximum speeds of 60 km/h on land and over 8 km/h in water. The system effectively satisfies the dynamic performance requirements, including velocity, acceleration, and gradeability, across the terrestrial, aquatic, and transitional phases. The simulation results indicate that the proposed HEPS configuration provides continuous tractive effort across the operating phases, achieving the required on-road design speed of 60 km/h, reaching approximately 8.7 km/h in calm-water operation, and attaining terminal transition velocities of approximately 7.2–9.5 km/h during the aquatic-to-terrestrial transition. This framework provides a useful analytical tool for the preliminary design and dynamic evaluation of hybrid amphibious vehicles.

Open Access

Article

Article ID: 4277

Electrostatic precipitators in the era of smart technology: Electrical efficiency, vibration mitigation, and noise reduction

by Junfeng Li, Yu Lu, Xinjiang Xu, Chunchun Sun, Qiliang Zhu, Dengke Zhao

Sound & Vibration, Vol.60, No.5, 2026;

Electrostatic precipitators (ESPs) are significant devices for particulate control in power generation, cement production, steel manufacturing, and other high-emission sectors. Future ESP performance should be evaluated not only on particle collection efficiency but also on electrical energy consumption, vibration stability, noise levels, reliability, and adaptive functionality. We proposed a three-layered framework for perception, analysis, and execution in intelligent ESPs. The perception layer combines electrical, emission, process, vibration, acoustic, and maintenance data; the analysis layer applies signal processing, artificial intelligence, digital twins, and multi-objective optimization; and the execution layer provides adaptive voltage control, rapping optimization, fan-speed control, vibration mitigation, active noise control, and predictive maintenance. The quantitative data show that intelligent electrical optimization can reduce ESP energy consumption by 35.50% and improve emission compliance from 95% to 100%. Approximately 43% energy saving was achieved by deep-learning-assisted voltage optimization in a 330 MW coal-fired power plant ESP. FFT, wavelet transform, RMS tracking, CNNs, LSTM models, and autoencoders can be used as diagnostic methods to detect imbalance, resonance, bearing faults, and fan irregularities, thereby reducing vibrations. Hybrid passive-active control for noise reduction can attenuate low-frequency duct noise by more than 10 dB and high-frequency components by more than 20 dB. This review highlights the absence of field-validated collaborative optimization as a significant knowledge gap and suggests digital twins, edge computing, 5G/6G communication, and multi-objective control as promising avenues for future research.

Open Access

Article

Article ID: 4310

Study of the mechanical behavior under compression of a tetrachiral auxetic tubular structure

by Ali Bejaoui, Ltaief Lammari, Fethi Abbassi, Ali Trabelsi, Mohamed-Ali Rezgui

Sound & Vibration, Vol.60, No.5, 2026;

Additive manufacturing enables the fabrication of architected materials with geometries unattainable through conventional processes. Among these, auxetic metastructures, characterized by a negative Poisson's ratio, have attracted considerable interest owing to their unusual deformation mechanisms and superior energy absorption and dissipation. This study investigates the mechanical behavior of a tetrachiral tubular structure made of AA7075-T651 aluminum alloy under axial compression, focusing on the influence of boundary conditions at the part–machine interfaces. Finite element simulations accounted for frictional contact, geometric nonlinearity, and the rotational kinematics of tetrachiral cells. The results reveal that friction governs the onset and magnitude of the auxetic response. Under highly constrained contact (μ = 0.8), ligament rotation is suppressed, and the structure deforms conventionally, exhibiting a positive effective Poisson's ratio (ν ≈ +0.28), limited twisting (two turns), and a maximum compressive load of 3.877 kN. Reducing friction to μ = 0.2 with a fixed base promotes in-plane node rotation, activating the tetrachiral mechanism and yielding ν ≈ −0.25, four turns, and a higher load of 3.883 kN. The most pronounced auxetic response arises when both ends are free to slide under low friction, producing ν ≈ −0.32, five turns, and an 8.2% contraction of the outer diameter. Across the investigated configurations, the effective Poisson's ratio varies by 0.60. These findings demonstrate that the auxetic behavior of tetrachiral tubes is highly sensitive to frictional and kinematic constraints, which must be carefully controlled to ensure reproducible mechanical performance.

Open Access

Article

Article ID: 4339

Dynamics of high-rise axisymmetric structures

by Mirziyod Mirsaidov, Sherzod Khudainazarov, Muhsin Teshaev, Talibjan Sabirjanov, Bakhtiyor Urinov, Ozodakhon Khaydarova

Sound & Vibration, Vol.60, No.5, 2026;

The article discusses the natural and forced oscillations of a "high-rise structure - dynamic vibration damper" system, focusing on its dynamic interactions. A mathematical model of this system has been developed, along with a calculation methodology, a numerical implementation algorithm, and a corresponding computer program that utilizes complex arithmetic tools for an accurate description of dynamic processes. Special attention was given to the viscoelastic properties of the structural material. The Boltzmann-Volterra hereditary law was applied to more accurately describe the time-dependent deformation characteristics. A practical example was explored using the high-rise smokestack of the Novo-Angren thermal power plant, which stands at 330 m tall. The natural oscillation frequencies of this structure were determined, and amplitude-frequency characteristics were constructed accounting for the presence of dynamic dampers and various kinematic impacts. During the problem-solving process, an analysis was conducted on how the parameters of both the structure and the effectiveness of the dynamic vibration damper (DVD) influence the system's response. Various combinations of system parameters were examined to identify patterns in changes to the dynamic response. Based on this research, optimal parameters for dynamic damping of oscillations were established for the real structure, leading to effective reductions in oscillation amplitudes and an increase in the reliability of the structure's operation under dynamic influences.

Open Access

Article

Article ID: 4336

Comparative analysis of simulation explosive methods in coupling charge

by Tao Yin, Fengzhuang Zhang, Huayong Guan, Ziru Guo, Chuanbo Zhou, Hongwei Li

Sound & Vibration, Vol.60, No.5, 2026;

The accuracy of numerical simulation for blasting behaviors is largely determined by explosive simulation methods. An equivalent amplified explosives method (method 2) for simulating explosives is proposed in this paper. A numerical model for large-diameter low-detonation-velocity explosives is developed to match the same total energy release in rock mass as small-diameter high-detonation-velocity explosives. Compared with existing equivalent methods that apply simplified blast vibration load curves to blast hole walls (method 3) and the plane of center line of blast holes (method 4), the proposed method can accurately characterize the detonation process of explosives and the thermodynamic properties of detonation products. The requirements and characteristics of four different explosive simulation methods are analyzed. Simulations of the blasting of open-pit iron mines were conducted via ANSYS/LS-DYNA, and the simulated vibration velocities obtained were compared with measured velocities. The results showed that field-measured vibration velocities were generally larger than numerical values from all four methods. Specifically, the fluid–structure coupling algorithm (method 1) required the most meshing work and is applicable to few blast holes and near-field analysis. Method 2 is suitable for simulating numerous blast holes and for studying and analyzing the middle and far regions of blast holes. Method 3 is applicable for simulating a few blast holes and for analyzing the middle and far regions of blast holes. Method 4 is also suitable for studying the middle and far regions of the blast holes. These results provide a reference for the numerical simulations of blasting processes under similar conditions.

Open Access

Article

Article ID: 4531

Integrated finite element and reduced-order modeling analysis of a real flat top tower crane system

by Mustafa Tınkır, Ali Çoban

Sound & Vibration, Vol.60, No.5, 2026;

This study presents the structural and dynamic analysis of a real 60/15 flat-top tower crane with a free-standing height of 48 m. Finite element analyses were performed to evaluate the stress distribution, deformation, and dynamic characteristics of the main structural components. Based on the finite element results, a 17-degree-of-freedom (17-DOF) reduced-order mathematical model was developed. The stiffness coefficients were obtained from the finite element deformations using Hooke's law, while the damping coefficients were determined analytically. An elastic multibody model of the crane was also developed in MATLAB/SimMechanics to validate the proposed reduced-order model. The finite element analyses showed that the maximum equivalent stress remained below the allowable stress limit (approximately 225 MPa), while the maximum displacement of the mast reached 183.94 mm under the design loading condition. Modal analysis indicated that the counter-jib had the lowest first natural frequency (0.64 Hz), making it the most flexible structural component of the crane. Under the same 2-t tip load, the maximum difference between the proposed 17-DOF model and the SimMechanics model was only 4.86% in the jib tip deflection. These results show that the proposed model can accurately represent the structural behavior of the crane while providing a computationally efficient reduced-order representation of the crane compared with detailed finite element modeling. The developed model provides a practical tool for structural analysis, vibration evaluation, design studies, and future control applications of real flat-top tower crane systems.

Open Access

Article

Article ID: 4590

Dynamic characterization and vibration response of high-speed milling for A2024-T351 aluminum alloy

by Rami Smari, Ltaief lammari, Ali Rakrouk, Ali Arfaoui, Sana BenKhlifa

Sound & Vibration, Vol.60, No.5, 2026;

A coupled finite element–finite difference framework was developed to simulate high-speed peripheral milling of A2024-T351 aluminum alloy, enabling the analysis of chip formation, thermal gradients, and dynamic instability. The finite element model was used to predict the thermo-mechanical response and chip formation, while the finite difference formulation was employed to solve the transient heat transfer under different cutting conditions. The workpiece plastic deformation was described using a Johnson–Cook (JC) constitutive law coupled with a cumulative damage model, whereas the tungsten carbide (WC) cutting tool was modeled as a thermo-elastic body. Mesh and time-step sensitivity analyses were performed to ensure numerical convergence and solution stability. Thermal fields and structural responses were evaluated as functions of cutting speed, feed rate, depth of cut, and milling strategy (climb and conventional). Time-resolved cutting force signals were analyzed using the fast Fourier transform (FFT) to correlate local chip segmentation with macroscopic vibration modes. The results showed that the maximum temperature stabilized after the engagement of the fourth tooth (739.6–742.5 K), with the majority of generated heat dissipated through chip evacuation. Compared with conventional milling, climb milling reduced the peak contact temperature by 6.5% and resulted in a smoother harmonic force response. Spectral analysis further showed a clear separation between the tooth-passing frequency (600 Hz) and the thermomechanical chip segmentation frequency (1,850 Hz). The numerical predictions were validated against experimental cutting parameter measurements, showing deviations below 5%. The proposed framework provides an effective predictive tool for analyzing high-speed milling and identifying cutting conditions that reduce structural vibration while maintaining thermal and mechanical performance.

Open Access

Article

Article ID: 4536

Rapid prediction of vehicle interior wind noise via a hybrid convolutional neural network-transformer model and geometric styling features

by Hongwei Yi, Penghu Li, Jifeng Wang, Yuwei Deng, Xiaorong Huang, Haibo Huang

Sound & Vibration, Vol.60, No.5, 2026;

The rapid evaluation of interior aerodynamic noise during the Concept A Surface design stage is important for vehicle acoustic development, but conventional methods are limited by high cost and low efficiency. This study proposes a convolutional neural network transformer-based prediction method for vehicle interior wind noise by integrating vehicle styling features and acoustic technical parameters. An optimal Latin hypercube sampling method was used to generate design combinations, and wind tunnel tests were conducted at 120 km/h. Key vehicle styling parameters, including A-pillar geometry, side mirror dimensions, front windscreen angle, side mirror-to-body spacing, and side window inclination, together with glazing material properties, glass thickness, acoustic transfer function, and interior reverberation time, were selected as input features to predict the driver’s left-ear wind noise spectrum. Based on five-fold cross-validation, the proposed model was compared with convolutional neural network (CNN), long short-term memory (LSTM), and transformer models. The CNN-Transformer model achieved the best performance, with mean absolute percentage error (MAPE) and root mean square error (RMSE) values of 2.23% and 0.94 dB, respectively. Compared with the transformer, CNN, and LSTM models, the proposed method reduced MAPE by 24.91%, 36.29%, and 49.59%, and reduced RMSE by 22.95%, 35.17%, and 48.07%, respectively. The model also maintained reliable performance on an independent test set, with MAPE and RMSE values of 4.82% and 1.44 dB. The mean impact value method was further applied to identify the influence of design parameters on interior wind noise, guiding for early vehicle acoustic optimization.

Open Access

Article

Article ID: 4108

Numerical analysis of freight wagon rolling dynamics on a classification hump

by Shuxrat Djabbarov, Bakhrom Abdullayev, Aziz Gayipov, Abdusaid Yuldashov, Nodir Botir o’g’li Adilov, Irina Soboleva

Sound & Vibration, Vol.60, No.5, 2026;

Accurate prediction of freely rolling freight-wagon speed is required to set retarder demand, maintain cut separation, and limit coupling energy in classification yards. This study develops a reproducible one-dimensional model of wagon motion along the first descending section of a classification hump. The governing equation combines the downslope gravitational component, equivalent mechanical resistance, aerodynamic drag based on signed relative air velocity, and rotating-mass inertia expressed through an effective mass. Three modelling levels are compared under identical initial conditions: gravity-only motion, constant mechanical resistance with rotating inertia, and the complete relative-wind formulation. Simulations cover a 60 m section, an initial speed of 0.50 m/s, wagon masses of 68 and 24 t, and track-aligned wind from a 12 m/s headwind to a 12 m/s tailwind. The gravity-only model overpredicts final speed by 7.8–19.7% for the loaded wagon and 3.2–41.3% for the empty wagon. For the loaded wagon, changing from headwind to tailwind raises final speed from 3.869 to 4.295 m/s and reduces travel time from 27.21 to 24.89 s. The time-stepping implementation agrees with the closed-form zero-drag solution to within 0.011%. A complete 2⁴ factorial design identifies wind, gradient, and equivalent resistance as the dominant factors and reveals a substantial wind–mass interaction. A 3,500-run Monte Carlo analysis yields final-speed percentiles of 3.659, 4.074, and 4.403 m/s at P5, P50, and P95, respectively. The model is suitable for preliminary yard assessment and measurement planning; operational use requires yard-specific resistance calibration and independent field validation using separate calibration and validation datasets.

Open Access

Article

Article ID: 4626

Alpha-cut robust design of a fractional-order fuzzy tuned mass damper for targeted-band vibration suppression in rotating machinery

by Yogeesh Nijalingappa, Asokan Vasudevan, Tahir Muhammad Ali, Rajashree Jain, P. William

Sound & Vibration, Vol.60, No.5, 2026;

This study presents a targeted-band design method for suppressing flexible-rotor vibration using a fractional-order fuzzy tuned mass damper. A force-excited rotor-support mode represents the host machine, while the absorber branch comprises a spring and fractional dashpot. The absorber parameters are selected to minimize the primary displacement peak while remaining robust to bounded uncertainty in mass ratio, tuning ratio, damping index, fractional order, support stiffness, and force level. Triangular fuzzy numbers are propagated through alpha-cut intervals, and the resulting frequency-response envelopes are optimized by a weighted objective that penalizes high peaks and wide uncertainty spreads. Closed-form frequency-response relations evaluated directly at interval corners keep the procedure transparent and reproducible. For a rotor-support oscillator with natural frequency 9.762 Hz, primary mass 42 kg, primary stiffness 158,000 N/m, force amplitude 58 N, and mass ratio μ = 0.05, the optimized design yields a central peak displacement of 1.929 mm and an alpha-zero upper peak of 3.154 mm, compared with 10.197 mm for the uncontrolled system and 2.028 mm for the deterministic Den Hartog reference. Evaluation at μ = 0.03, 0.05, and 0.07 shows consistent peak reduction and useful trends for initial parameter tuning. The method therefore provides bounded vibration envelopes, tuning guidance, stroke estimates, and sensitivity rankings for uncertain rotating-machine data within the specified target band.

Open Access

Article

Article ID: 4627

Analytical design and multi-parameter optimization of micro-perforated double-panel partitions for normal-incidence broadband sound transmission loss

by Tahir Muhammad Ali, Yogeesh Nijalingappa, Asokan Vasudevan, Rajashree Jain K S, P. William

Sound & Vibration, Vol.60, No.5, 2026;

An analytical and computation-based framework is presented for designing a micro-perforated double-panel partition with improved broadband sound transmission loss. The study combines closed-form expressions, transfer matrices, dimensionless design parameters and tabulated numerical values to support practical acoustic design. In the present work, a thin micro-perforated panel is asymmetrically inserted into the cavity spanning between two parallel panels that are separated by an air cavity forming coupled resonant mechanisms. This normal-incidence transfer-matrix model is composed of panel impedances, cavity propagation matrices and Maa-type micro-perforate impedance formulas. A local Helmholtz-type estimate of transmission loss and the mass-air-mass resonance are stated explicitly, followed by a simultaneous optimization of hole diameter, perforation ratio, micro-perforated sheet thickness and cavity split over a target frequency band. Over the 100–2,000 Hz band, the optimized asymmetric micro-perforated design improves the weighted average transmission loss by 6.49 dB and the arithmetic band-average transmission loss by 9.33 dB relative to the baseline double panel, with the strongest gains occurring in the upper octave bands. Parameter sweeps show that smaller perforations and slightly asymmetric cavity splits yield the best broadband trade-off for this case. Because the optimum occurs at the stated lower manufacturing bounds, it is interpreted as a constrained design result. Diffuse-field incidence, elastic plate dynamics, manufacturing tolerances, and experimental validation remain for future work.

Open Access

Review

Article ID: 4225

Cooperative design of broadband vibration energy recovery and thermal management for structural-exhaust systems in intelligent connected vehicles: A review

by Chao Wang

Sound & Vibration, Vol.60, No.5, 2026;

The rapid advancement of intelligent connected vehicles (ICVs) has placed new demands on distributed electronic systems and increased the number of on-board functions that involve sensing, communication, and control. Unlike conventional vehicles, ICVs have significantly higher energy demand, and real-time sensing, communication, and control capabilities are much more feasible and are key to enabling cooperative vibration-thermal design. Structural-exhaust systems are subjected to broadband vibrations and extreme temperatures at all times and therefore seem to be a good platform for waste energy recovery and thermal control. Vibration energy harvesting and exhaust thermal management have been widely studied, but they are mostly implemented individually as subsystems. This separation ignores the thermo-mechanical coupling in exhaust structures and typically results in inefficient energy recovery and poor thermal and/or structural performance. A thorough review of the cooperative design of broadband vibration energy recovery and thermal management for the structural-exhaust system of an ICV is presented. The vibration and thermal performance of exhaust systems, and the coupling mechanisms between them, are investigated to elucidate fundamental design issues. A review of state-of-the-art broadband vibration energy harvesting technologies and exhaust thermal management technologies is conducted, highlighting their limitations operating under coupled conditions. Cooperative design concepts, structural integration strategies and multi-physics modelling and optimization methods are explained. Adaptive control, vehicle-to-everything connectivity, data-driven techniques, digital twins and system-level validation are emphasized. Lastly, problems are identified, and areas for further research are suggested.

Open Access

Article (This article belongs to the special issue "Intelligent Systems in Sound and Vibration Analysis")

Article ID: 4705

A multimodal explainable AI framework for industrial turbine vibration health monitoring and regulatory decision support in finance

by Alexey Mikhaylov, Sergey Barykin, Daria Dinets, Vasilii Buniak, Oksana Solodchenkova, Elena Sidorova, Tatyana Kirillova, Elvira Rustenova, Miras Kilau, Gumar Batov, Akram Ochilov, Yuri Sotskov, Tomonobu Senjyu, Mahmoud Delavar, N.B.A. Yousif, Anthony Nyangarika

Sound & Vibration, Vol.60, No.5, 2026;

Industrial rotating machinery plays a pivotal role in global energy infrastructure, yet conventional vibration monitoring systems often operate as black boxes, providing limited interpretability and failing to leverage the rich multi-sensor data available in modern plants. This paper introduces a novel framework that integrates multimodal sensor fusion—combining accelerometer, acoustic, thermal, and operational data—with explainable artificial intelligence (XAI) and multi-criteria decision analysis. The core engine is a domain-collaborative multimodal transformer that jointly processes heterogeneous time-series and image-based streams, producing fault classifications alongside SHapley Additive exPlanations (SHAP)-based feature attributions and natural-language diagnostic narratives. The framework is validated on a 250 MW combined-cycle gas turbine power plant with 24 months of operational data. Experimental results demonstrate a fault detection accuracy of 94.2%, a 14.5% improvement over vibration-only baselines, while achieving the highest interpretability score (5/5) among compared methods. Decision Making Trial and Evaluation Laboratory (DEMATEL) causal analysis identifies diagnostic transparency and system reliability as primary drivers of regulatory compliance. The primary contribution is an open-source, scalable blueprint for trustworthy AI in industrial vibration monitoring, addressing the urgent need for transparent, auditable, and human-centered decision support in critical energy assets. The proposed framework achieves a balanced integration of three critical dimensions: diagnostic accuracy and interpretability, technical performance and regulatory compliance, and automated inference and human oversight. Based on these findings, we recommend that industrial operators for finance risk optimization: (1) deploy multimodal sensor arrays combining vibration, acoustic, thermal, and operational sensors; (2) implement explainable AI protocols utilizing SHAP-based feature attribution; and (3) adopt DEMATEL-derived priorities for risk-informed maintenance scheduling.