Vol. 60 No. 3 (2026): In Progress

Open Access

Article

Article ID: 3908

Inverse engineering of micro-perforated plates for targeted acoustic characteristics

by Binxia Yuan, Xiangyang Li, Tianqi You, Tianzhong Chen, Rui Zhu

Sound & Vibration, Vol.60, No.3, 2026;

The inverse design of micro-perforated panels (MPPs) for target sound absorption remains challenging due to the complex nonlinear relationship between structural parameters and acoustic performance. This study proposes a tandem neural network (TNN) framework to achieve efficient inverse design of single-layer MPPs. A forward multi-layer perceptron (MLP) is first trained to accurately predict the absorption coefficient curve from three key structural parameters: perforation diameter, panel thickness, and cavity depth. The forward model achieves superior accuracy compared to GA-SVR, GridSearch-SVR, and random forest models, with an R² of 0.999 and MAE of 0.007. Subsequently, an inverse design network is connected in series with the frozen forward network, taking a target absorption curve as input and outputting the corresponding structural parameters. The activation function of the output layer constrains the parameters within physically feasible ranges. The framework is validated by designing an MPP with a distinct absorption peak in the 300–600 Hz range. The predicted parameters (diameter 0.93 mm, thickness 0.9 mm, cavity depth 9.9 mm) yield an absorption curve that matches the target with an R² of 0.997. This work demonstrates that deep learning can effectively automate the inverse design of MPPs, offering a flexible and efficient alternative to traditional trial-and-error methods.

Open Access

Article

Article ID: 4070

Fuzzy-stochastic coupled models for broadband noise radiation from flexible

by Suleiman Ibrahim Mohammad, Yogeesh Nijalingappa, Basem Abu Zneid, Shashikumar Honnavalli Channabasavaiah, Asokan Vasudevan, Jayaprakasha Pathiyappanapallya Chandraiah

Sound & Vibration, Vol.60, No.3, 2026;

Broadband noise radiation from flexible panels is governed by the coupling of random excitation fields with uncertain structural and boundary parameters. This paper develops a fuzzy-stochastic vibro-acoustic framework that separates (i) aleatory uncertainty in the broadband pressure field from (ii) epistemic uncertainty in panel properties and mount conditions. The panel dynamics are modeled in the frequency domain using a modal or finite-element representation of the thin-plate operator, while acoustic radiation is evaluated through a baffle-mounted radiation model leading to radiated sound power spectra. Random excitation is represented by the pressure cross spectral density, enabling direct propagation of spectral statistics to displacement and velocity cross-spectra via linear transfer functions. Epistemic uncertainty in Young's modulus, thickness, and loss factor is represented by fuzzy numbers and propagated through α-cuts, yielding interval-valued parameter sets at each α level. The coupling is implemented using an α-cut outer loop with a stochastic inner solver that computes mean and variance of radiated sound power; α-level interval extrema then provide fuzzy envelopes of stochastic response metrics. Verification is performed through modal truncation, frequency-grid stability, and α-grid refinement. Numerical demonstrations using representative datasets show that epistemic uncertainty can induce wide bands in band-integrated sound power level (≈9.9 dB in the 100–1,000 Hz band at α = 0), and that percentile metrics (e.g., 95th percentile under a lognormal approximation) provide conservative bounds for design decision-making. The proposed framework offers a transparent and computationally tractable route to uncertainty-aware broadband vibro-acoustic prediction for panels in vehicles, buildings, and machinery enclosures.

Open Access

Article

Article ID: 4017

Optimization and experimental study of low-frequency sound absorption performance for modified sonic black hole

by Ziyan Chen, Qibo Mao, Lihua Peng

Sound & Vibration, Vol.60, No.3, 2026;

The design of a sound absorber with simultaneous broadband and low-frequency absorption is still difficult to achieve. Most existing noise reduction techniques target only a single aspect of the acoustic performance. The difficulty lies in the inherent trade-off between compact size, broad bandwidth, and effective low-frequency absorption. To overcome these issues, this study proposes a modified sonic black hole (SBH) to enhance the conventional SBH structure's low-frequency broadband sound absorption capabilities. By introducing the concept of equivalent length, this study adjusts only the opening area of the SBH structure without increasing its length, thereby equating the modified SBH to an original SBH with a longer geometric length. This equivalent extension enhances the coupling between the structure and low-frequency sound waves, thereby improving the low-frequency sound absorption performance. Theoretical modeling and simulation analysis demonstrate that reducing the SBH inlet diameter (or ring maximum inner diameter) can effectively improve the SBH low-frequency sound absorption effect. Furthermore, experimental comparisons of modified SBHs under different inlet diameters reveal that reducing the diameter from a fully open (95 mm) to 30 mm reduces the SBH’s first natural frequency from 615 Hz to 225 Hz, demonstrating a marked improvement in low-frequency sound absorption performance. The proposed modified SBH concept provides a promising solution for low frequency and broadband noise control.

Open Access

Article

Article ID: 3994

Analysis of an existing methodology for assessing vehicle-track interaction under reliability conditions

by Shuxrat Djabbarov, Bakhrom Abdullayev, Aziz Gayipov, Abdusaid Yuldashov, Nodir B. Adilov, Irina Soboleva

Sound & Vibration, Vol.60, No.3, 2026;

This paper presents a focused analytical audit of two simplified vehicle-track interaction schemes reported in the State Standard for 1,520 mm Gauge Railways: (i) a wheel-on-rail stability scheme intended to characterize flange-climb resistance and (ii) a track lateral stability scheme intended to estimate sleeper-rail-grid shift under train loading. The aim is twofold: first, to identify the internal inconsistencies of these specific formulations; second, to derive general lessons for transparent and reproducible safety assessment in railway engineering. The audit is organized around three steps: reconstruction of the source free-body diagrams and symbol definitions, point-by-point consistency checks of the equilibrium relations, and formulation of corrected self-contained equations in a unified coordinate system. The revised presentation shows that the source schemes mix force and moment terms, use ambiguous coordinate conventions, and in several places produce self-referential or physically trivial coefficients. A compact worked example is provided to illustrate the numerical difference between a parameter-independent source-style ratio and the corrected parameter-dependent contact-equilibrium relation. The paper also clarifies the status of each figure as either adapted from the source schemes or reconstructed by the authors and condenses the normative background to the material strictly needed for interpretation. Overall, the revised workflow improves traceability, reproducibility, and engineering interpretability.

Open Access

Article

Article ID: 2034

Articulation index-based acoustic signal processing for enhanced speech intelligibility

by Mahesh Shankarrao Patil, Vijaykumar Varadarajan, Harsha Jitendra Sarode, Farook Sayyad, Rahul Krishna Sarawale, Shabnam Sayyad, Deshinta Arrova Dewi

Sound & Vibration, Vol.60, No.3, 2026;

This paper presents an innovative approach to improving speech intelligibility using the wavelet transform and the Articulation Index (AI) as an objective evaluation metric. Conventional methods such as the Modified Rhyme Test (MRT) and Mean Opinion Score (MOS) rely on subjective assessment, making them time-consuming and difficult to standardize. In contrast, AI provides a consistent and reliable measure of speech intelligibility across varying noise conditions. The proposed method applies wavelet packet transform to noisy speech signals, followed by a thresholding function to enhance signal quality and intelligibility. The processed speech is then reconstructed using the inverse wavelet transform. Experiments are conducted using the Noiseus database, which contains speech signals corrupted by real-world noises such as streets, airports, cockpits, and industrial environments like mechanical factories, with noise levels ranging from 0 dB to 15 dB. Three different enhancement methods are implemented, with the proposed method demonstrating superior performance in terms of AI values. Experimental validation is supported by plots and spectrograms, highlighting its effectiveness over existing approaches. The method leverages the multi-resolution property of the wavelet transform to preserve temporal characteristics while reducing noise across multiple frequency bands. Results show a significant improvement in AI values, indicating enhanced speech intelligibility under diverse noise conditions. This work contributes to acoustic speech enhancement by providing a robust, objective framework suitable for applications in noisy environments such as industrial communication systems, and this technique aligns closely with noise mitigation approaches used in structural and industrial surroundings. Additionally, the approach can be extended to industrial speech enhancement and environmental noise control.

Open Access

Article

Article ID: 4106

Timbre transfer of classical guitars using impulse response and a laser displacement sensor

by Che-Hsu Yeh, Chii-Chang Chen

Sound & Vibration, Vol.60, No.3, 2026;

Conventional characterization of musical instruments relies on microphones, whose measurements depend strongly on distance, sound radiation directionality, and the non-uniform frequency responses of microphones and preamplifiers, often introducing distortions. Laser displacement sensors, widely used for vibration and surface measurements, offer a higher maximum displacement–to–resolution ratio than laser Doppler vibrometry. Measuring instrument vibrations with such sensors enables the capture of a more intrinsic acoustic source. This study demonstrates timbre transfer from a hand-made guitar to a José Ramírez guitar using convolution with impulse responses obtained from both a laser displacement sensor and a microphone. Timbre similarity is evaluated via cross-correlation of acoustic spectra between original and transferred notes. For 33 notes (E2–C5), the laser-based method yields higher cross-correlation in 28 cases compared to the microphone-based approach. The results highlight the distinction between vibration-based and pressure-based timbre characterization. Microphone measurements capture far-field sound pressure along with environmental noise, whereas laser displacement sensing directly reflects the instrument’s vibrational behavior. Consequently, laser-based impulse responses provide a more intrinsic representation of acoustic spectra and enable more accurate timbre transfer. After recording a performance, the timbre of one instrument can therefore be transferred more precisely to another using impulse responses derived from laser displacement sensors.

Open Access

Article

Article ID: 4116

Hidden-state unscented Kalman filter with unknown input for the joint identification of 3D structural parameters and unknown excitation

by Lijun Liu, Yahan Yang, Shiyu Wang, Ying Lei, Yujue Zhou, Nan Gong

Sound & Vibration, Vol.60, No.3, 2026;

The unscented Kalman filter with unknown input (UKF-UI) is an effective method for the identification of structural system and unknown excitation, but for three-dimensional multi-degree-of-freedom structures, the joint identification of structural state-parameter-unknown excitation often leads to high dimensions of extended state vector. To address this issue, a hidden-state unscented Kalman filter with unknown input is proposed for the joint identification of structural parameters and unknown excitation of three-dimensional structures. In the proposed method, only the time-invariant structural parameters are included in the structural state vector, while the displacements and velocities of all structural degrees of freedom are defined as hidden states and excluded from the state vector. This explicitly avoids the conventional extended state vector containing displacement, velocity and structural parameters. By reducing the state vector dimension, the identification of joint structural state-parameter is reduced to parameter-only identification. Moreover, the unbiased minimum variance estimation is used to achieve synchronous identification of unknown excitation. It avoids prior assumptions about unknown excitation and enhances the applicability in practical engineering. The identification of a three-dimensional frame structure under unknown excitation is used to verify the effectiveness of the proposed method. Through the observation of partial acceleration and displacement response data, structural element parameters of the three-dimensional structure and the unknown excitation acting on the three-dimensional structure can be identified.

Open Access

Article

Article ID: 3951

Type-1 fuzzy inference system for epistemic uncertainty quantification in computational vibro-acoustic simulations

by Yogeesh Nijalingappa, Asokan Vasudevan, Mohammed El Khider, Puspanathan Doraisingam, Khan Sarfaraz Ali, Pradeepa Balasubramanium

Sound & Vibration, Vol.60, No.3, 2026;

Type-1 fuzzy inference is incorporated into computational vibro-acoustic simulations to quantify epistemic uncertainty in sound pressure level (SPL) predictions arising from uncertain damping, boundary impedance, excitation level, and material parameters. The proposed formulation represents uncertain inputs through α-cut intervals and propagates them through a deterministic vibro-acoustic solver to obtain bounded response envelopes over the frequency range of interest. A compact Mamdani-type fuzzy inference system is then used to map physically interpretable descriptors, including band-limited SPL behavior, peak-to-average characteristics, and response trend measures, to lower and upper bounds of the selected quantities of interest together with a normalized uncertainty-width index. The framework is intended for cases in which precise probability distributions are not available, but bounded engineering knowledge or expert judgment is available. The study further defines a leakage-safe calibration and validation procedure, frequency-band reporting metrics, and sensitivity-based ranking of uncertain factors. The resulting framework offers an interpretable and solver-compatible route for uncertainty-aware reporting in vibro-acoustic analysis. The method was formulated to produce engineering-usable uncertainty statements—namely, frequency-dependent lower/upper Qol envelopes  and an uncertainty width index , while preserving transparency through interpretable membership functions and rule activations. This paper presents a Type-1 Fuzzy Inference System (FIS) framework for uncertainty quantification (UQ) in computational vibro-acoustic simulations, designed to sit directly on top of standard deterministic VA solvers.

Open Access

Article

Article ID: 4136

Bifurcation and chaos analysis of gear-bearing system with fractal mesh stiffness and fractal friction excitation

by Wei Liu, Ying Cui, Qiang Wang

Sound & Vibration, Vol.60, No.3, 2026;

Studying tooth surface topography and sliding friction in gear-bearing system is crucial for enhancing its reliability and minimizing vibration and noise. Inspired by preliminary research on sliding friction, this study addresses a novel gear-bearing model, in which the fractal meshing stiffness and fractal friction excitation are emphasized simultaneously. Initially, the formula of time-varying meshing stiffness (TVMS) due to fractal characterization is developed by employing the W-M function. The influence of fractal dimension on TVMS is investigated. Subsequently, the sliding friction excitation corresponding to fractal dimension is derived and introduced into the proposed gear-bearing model. On this basis, the bifurcation and chaos of the gear-bearing system with and without fractal dimension are compared. The maximum Lyapunov exponent forecasting methodology is carried out to validate the dynamic characteristics. In order to clearly exhibit the influence of the fractal dimension, the nonlinear dynamic behaviors of the gear-bearing system are investigated by reference to its time-domain chart, phase diagram, frequency spectrum, and Poincare section. Ultimately, contributions of sliding friction on dynamic behaviors of gear-bearing system are also examined. This work is extremely significant for improving the gear dynamic performance through guiding gear surface design and manufacture.

Open Access

Article

Article ID: 4089

Dynamic modeling of ball screw feed systems: A review and framework from physical mechanisms to a physics–data hybrid approach

by Yongqiang Li, Saiful Bahri Bin Mohamed, Mohd Shahir Bin Kasim, Siti Nurul Akmal Binti Yusof

Sound & Vibration, Vol.60, No.3, 2026;

Ball screw feed systems demonstrate that pronounced nonlinearity, time variation, and multiphysics coupling arise under high speed, high acceleration, and long-duration operation, where neither purely physics-based nor purely data-driven models can simultaneously ensure interpretability, deployability, and cross-condition reliability. However, the significant challenges this presents show that a more integrated framework could address these limitations more effectively. Moreover, the findings from existing approaches indicate that a Coupled Mechanism–Model–Data (CMMD) framework could provide a systematic way to connect physical mechanisms with application-oriented modeling through a hierarchical and constrained architecture. In light of these key results, the evidence shows that following a unified logic of "mechanism coupling–model structure–data updating interface" appears to support more coherent analytical development. Research shows friction, stiffness, thermal deformation, and wear affect modal properties. Nevertheless, the important propagation effects indicate that formulating these as identifiable nonlinear and time-varying terms demonstrates that the framework retains critical physical interpretability. Furthermore, the evidence shows that hierarchical physics-based model families appear to differ significantly in representational capability, computational cost, and boundary sensitivity. Given that the findings demonstrate that conditions involving strong nonlinearity and parameter drift present particular analytical difficulty, LPV–NARX (Linear Parameter-Varying Nonlinear AutoRegressive model with eXogenous inputs), sparse identification, neural networks, and three hybrid paradigms—residual compensation, adaptive parameter updating, and physics-constrained learning—indicate that synthesis according to fusion location, updating objects, and failure boundaries could establish a constraint-driven hierarchical selection strategy. Data shows hybrid paradigms yield representative application scenarios.

Open Access

Article

Article ID: 3981

Mathematical and numerical modeling of resonant frequencies of fluid-structure systems for digital twins

by Bauyrzhan  Amirkhanov, Gulshat Amirkhanova, Murat  Kunelbayev, Alina  Raeva

Sound & Vibration, Vol.60, No.3, 2026;

This research establishes a comprehensive mathematical and numerical framework for accurately predicting the resonant frequencies of fluid-filled thin-walled structures, a critical factor in the safety and performance of engineering systems such as storage tanks, pipelines, and aerospace components. The study addresses the inherent limitations of classical analytical solutions, which are typically restricted to idealized geometries and cannot account for the complexities of real-world applications. By coupling the Navier-Lamé equations for elastic shell motion with the Laplace equation for the fluid domain, the model effectively captures the "added mass effect"—the phenomenon where internal fluid interaction significantly reduces a structure's natural frequencies. This effect is particularly pronounced in systems with denser fluids, larger radii, and thinner walls. The proposed framework was rigorously validated against a diverse dataset of 54 experimental cases from peer-reviewed literature, covering various geometries (spheres, cylinders, and square plates) and materials including glass, steel, and aluminum. The results demonstrated exceptional reliability, with an average relative error of less than 0.5% across all tested configurations. Statistical analysis, including Boxplots and Empirical CDFs, further confirmed that the model maintains sub-percent-level accuracy, with 100% of cases showing less than 1.1% error. Implemented within the ANSYS finite element environment, the model's computational efficiency and high precision make it an ideal tool for integration into digital twin systems. Such integration enables real-time dynamic monitoring and predictive maintenance of complex industrial infrastructure. Future developments aim to enhance the model by incorporating nonlinear fluid effects, such as sloshing, and integrating these simulations into Industrial Internet of Things (IIoT) frameworks.

Open Access

Article

Article ID: 4129

Non-contact full-field vibration measurement using 3D digital image correlation: Experimental validation against accelerometers in multi-axis dynamic testing

by Suleiman  Ibrahim Mohammad, Asokan  Vasudevan, Seif Al  Bustanji

Sound & Vibration, Vol.60, No.3, 2026;

Accurate measurement of such vibrations is a prerequisite for any research work in the field of structural dynamics, modal analysis, and evaluation of machinery reliability. Although accelerometers are traditionally used for experimental vibration analysis, their use is also associated with certain limitations such as mass loading effects and under-sampling issues. Non-contact full-field vibration measurement techniques such as three-dimensional digital image correlation (3D-DIC) have also emerged as potential alternatives for vibration measurement. However, their comprehensive evaluation for full-field vibration measurement under broadband random excitations is still limited. This paper presents an experimental evaluation of the full-field vibration measurement technique using 3D-DIC for vibration measurement. The performance evaluation of the technique is also carried out using a conventional vibration measurement technique such as accelerometers. A ribbed aluminium cantilever plate is subjected to controlled broadband random excitations, and the vibration response is measured using a stereo high-speed full-field vibration measurement technique such as 3D-DIC and a triaxial accelerometer. The comparative analysis showed considerable concurrence between the two systems in the assessment of the displacement amplitude tracking, resonance identification, and modal shape characterization. Statistical evaluation showed the absence of any statistically significant difference in the mean displacement measurement within the established industrial tolerance limit. The optical system provided continuous spatial resolution and multi-axis displacement mapping without the application of any structural mass loading. This shows the equivalence and the industrial applicability of the 3D-DIC method for broadband multi-axis dynamic testing, thus making it suitable for the analysis of the vibration behaviour of the structure.

Open Access

Article

Article ID: 4199

Grouped inerter-resonator arrays for broadband reduction of plate mobility and radiated sound power using modal receptance synthesis

by Yogeesh Nijalingappa, Asokan Vasudevan, Mustafa Abdullah, Shankaralingappa Bheemasandra Marulappa, Suleiman Ibrahim Mohammad, Ashalatha Kodihalli Siddagangaiah

Sound & Vibration, Vol.60, No.3, 2026;

A plate-type vibroacoustic treatment is developed in which a simply supported Kirchhoff plate is coupled to a grouped array of parallel spring-damper-mass-inerter attachments. The emphasis is intentionally computational. The plate equation is reduced to a modal receptance form using 36 orthogonal sine modes, and the local attachments are eliminated analytically so that each attachment contributes a rank-one dynamic stiffness term. The resulting frequency-domain matrix remains explicit and can therefore be evaluated over large parameter grids without rederiving the governing equations. For the present plate, the bending rigidity is , the areal density is , the planform area is , and the total plate mass is . The sixteen attachments are arranged on a  grid and grouped columnwise at target frequencies, which are  Hz. With the reference internal mass , inertance ratio , tuning scale 0.9, spread coefficient 0.18, and damping ratio , the grouped inerter-resonator array yields average reductions of  dB in point mobility and  dB in both mean-square velocity and radiated sound-power proxy over 80–600 Hz. The spring-mass reference under identical internal mass produces corresponding lower averages of  and  dB. As per this study, the peak-by-peak reductions exceed 20 dB at several dominant modal peaks, while tuning scatter of 5% root-mean-square leaves the average velocity reduction essentially unchanged.