Vol. 59 No. 4 (2025)

Open Access

Article

Article ID: 3523

Multi-dimensional evaluation and prediction of vibration comfort in electric loaders using ACO-Transformer

by Ruxue Dai, Jian Zhao, Qingli Sui, Weidong Zhao, Weiping Ding, Haibo Huang

Sound & Vibration, Vol.59, No.4, 2025;

Engineering machinery plays a vital role in supporting modern economic development. The electric loader represents a key innovation driven by environmental protection and the pursuit of sustainable development. However, the absence of engine masking effects in electric machinery makes structural vibration and impact noise more pronounced. To address this issue, this study proposes an ant colony optimization-Transformer (ACO-Transformer) model that integrates the ant colony algorithm with the Transformer framework to accurately and efficiently evaluate the vibration comfort of electric engineering machinery. An improved objective evaluation method for vibration was employed to extract objective data from four measurement points, while 34 subjective scores were obtained through a structured subjective evaluation protocol. The combined analysis of subjective and objective data demonstrated the validity of incorporating additional vibration measurement points. Using these datasets, the ACO-Transformer model was developed to establish a mapping between multi-dimensional objective vibration parameters and subjective comfort ratings. Results indicate that the proposed model achieved high prediction accuracy (MAPE = 6.22%) and strong generalization performance (RMSE = 6.11). This study offers a novel approach for evaluating and predicting the vibration comfort of engineering machinery cabins.

Open Access

Article

Article ID: 3717

Signal analysis of elastic waveguide-based techniques for monitoring bone fracture healing: application to structural state evolution in biological composites

by Wei Li, Xiaoya Li, Jingya Wu, Xiao Liang

Sound & Vibration, Vol.59, No.4, 2025;

This study explores the use of elastic waveguide propagation and signal analysis for monitoring structural evolution in heterogeneous media, with bone analogues employed as a case example. Synthetic models representing low, intermediate, and high stiffness states were examined using piezoelectric sensors to capture transmitted waveforms. Four parameters velocity, attenuation, dispersion index, and spectral entropy were extracted according to defined procedures. Results showed consistent trends: velocity increased, attenuation decreased, dispersion diminished, and entropy reduced as stiffness increased, confirming the sensitivity of wave-derived features to structural transitions. A Random Forest classifier was applied to these features, demonstrating highly accurate discrimination among the three states under controlled conditions. The integration of elastic wave descriptors with supervised learning highlights the potential of vibration-based diagnostics for tracking stiffness evolution in heterogeneous composites. While bone consolidation provides a compelling case study, the framework is generalisable to other composite systems, thereby reinforcing the contribution of elastic wave analysis to the broader field of sound and vibration.

Open Access

Article

Article ID: 3381

Dynamic stability of a damped nonlinear axially moving beam resting on the nonlinear elastic foundation

by Ghulam Yameen Mallah, Rajab Ali Malookani, Muhammad Memon, Muzaffar Bashir Arain, Izhar Ali Amur

Sound & Vibration, Vol.59, No.4, 2025;

The stability of nonlinear transverse vibrations of an axially moving beam resting on a nonlinear elastic foundation is analysed, considering the effects of viscous damping and a harmonically varying time-dependent velocity around a low constant mean speed. The beam is assumed to have simply supported boundary conditions at both ends. The contribution of this paper is the combined study of damping, nonlinear foundation, and harmonic velocity variation on the stability of axially moving beams, which has not been studied before. The governing equation for the transverse dynamics is a nonlinear partial differential equation with variable coefficients, which is solved using the two-timescale perturbation method in combination with the Fourier series method. The stability of the system is investigated for both non-resonant and resonant cases by examining the influence of key parameters, including nonlinear bending stiffness, nonlinear elastic foundation and damping. The analysis reveals that an increase in nonlinear bending stiffness and nonlinear elastic foundation tends to destabilize the system, leading to growing oscillations and instability. In contrast, an increase in damping enhances stability, causing oscillations to decay over time and leading to an asymptotically stable response. Furthermore, validation was carried out through comparison with an existing model.

Open Access

Article

Article ID: 3552

Assessment of two-phase unsteady leakage flow induced blade vibration in subsea counter-rotating axial flow compressor

by Weizheng An, Zhengyuan Li, Yuan Tao, Guangfeng An, Liya Zhu

Sound & Vibration, Vol.59, No.4, 2025;

As a novel lift method for subsea oilfield development, the subsea counter-rotating axial compressor can achieve a higher pressure ratio with a smaller size through a row of counter-rotating blades. However, unsteady tip leakage flow inevitably exists due to the clearance between blade tips, which may cause blade vibration and lead to fatigue failure eventually. Here, a numerical study based on fluid-structure interaction analysis is conducted on a laboratory subsea counter-rotating compressor to investigate its tip leakage flow-induced vibration characteristics. Firstly, the unsteady two-phase flow field is simulated using computational fluid dynamics. Flow characteristics and aerodynamic force are obtained. Then, the aerodynamic force is loaded on the blade surface to achieve the one-way fluid-structure interaction analysis. Finally, finite element analysis simulations are performed to obtain the blade vibration characteristics. Simulation results show that rotating speed has a dominant influence on high-cycle fatigue failure. A potential fatigue risk is identified at 4250 rpm, where the maximum stress (680–713 MPa) exceeds the yield strength (580 MPa) of the blade material. A two-phase turbulence unsteady flow model is established here to simulate the state of the working fluid more accurately. A simplified unsteady flow simulation method for counter-rotating compressors is applied to save computational cost. Besides, the fluid-structure interaction analysis technique presented here helps understand blade vibration mechanisms, facilitating anti-vibration design with reduced reliance on physical experiments. It also serves to identify potential fatigue failures caused by unsteady tip leakage flow, ensuring the secure operation of subsea counter-rotating axial compressors.

Open Access

Article

Article ID: 3645

AS-FCRNet: a lightweight multi-frame acoustic–seismic fusion network for high-precision ground moving target recognition on UGS

by Zheyu Liu, kunsheng Xing, Wei Wang, Nan Wang

Sound & Vibration, Vol.59, No.4, 2025;

To address the challenges of high computational complexity and temporal modeling difficulties caused by high-dimensional data in acoustic and seismic signal classification, this paper proposes a multi-stage dimensionality reduction and classification framework based on the integration of Mel-frequency spectrum feature extraction, Convolutional Neural Networks (CNNs), and Long Short-Term Memory (LSTM) networks. The method significantly reduces computational complexity while maintaining competitive classification accuracy through progressive feature compression and acoustic-seismic feature fusion. Specifically, Mel-frequency spectrum feature extraction is first performed on dual-channel input signals (acoustic and seismic) to extract perceptually relevant physical features aligned with human auditory characteristics. Then, a lightweight CNN is designed to perform further feature extraction on log-Mel energy representations; in the fusion stage, we investigate three fusion strategies (information-level, feature-level, and decision-level fusion) for acoustic and seismic signals to identify the optimal approach, before fusing the information and compressing the fused features into a short vector for subsequent temporal modeling. A sequence of compact feature vectors extracted from consecutive frames (e.g., four-frame segments) is fed into an LSTM network to capture temporal dependencies, and the final classification is performed based on the output of the last time step. Experimental results demonstrate that the proposed approach effectively balances inference efficiency and model performance, achieving accurate and reliable classification results with low computational complexity.

Open Access

Article

Article ID: 3533

Smart tilted FBG sensors for strain monitoring in wooden beams

by Aliya Kalizhanova, Murat Kunelbayev, Ainur Kozbakova

Sound & Vibration, Vol.59, No.4, 2025;

his paper reports the design, fabrication, and experimental validation of smart tilted fiber Bragg grating (TFBG) sensors embedded within the internal structure of wooden beams for real-time strain and deflection monitoring. Pine and oak specimens were instrumented with five multiplexed FBGs distributed along the span and tested under a constant end load to capture the strain field during bending. To mitigate temperature-induced bias in the deflection analysis, a dedicated reference FBG was placed in a non-deflecting zone and used to compensate the individual temperature response of each sensing element. The optical transducers were encapsulated in epoxy-impregnated carbon fabric to ensure reliable strain transfer, mechanical protection, and long-term stability without compromising the host material. Wavelength-shift demodulation and in-situ calibration provided separate estimates of strain and temperature, enabling accurate reconstruction of the beam shape. The temperature-compensated measurements showed close agreement with Euler–Bernoulli beam predictions for both wood species, with correlation coefficients exceeding 0.87 across all trials. The sensing system exhibited repeatable behavior and low hysteresis, while the embedded configuration preserved the structural integrity and allowed unobtrusive installation. Overall, the results demonstrate that smart TFBG sensors are a practical and effective solution for embedded structural health monitoring of timber members, offering high accuracy, electromagnetic immunity, and seamless integration into load-bearing components. The approach is readily scalable to multi-sensor arrays and mixed materials, paving the way for continuous monitoring of civil and architectural wooden structures.

Open Access

Article

Article ID: 3496

Fuzzy-grey relational optimization for active vibration control in smart composite beams: a multi-objective framework with experimental validation

by Yogeesh N, Markala Karthik, N Raja, Asokan Vasudevan, Rashmi M, Ashalatha K S

Sound & Vibration, Vol.59, No.4, 2025;

This paper presents a hybrid fuzzy logic–grey relational analysis (Fuzzy–GRA) framework for multi-objective optimization of active vibration control (AVC) in smart composite beams. A fuzzy-adaptive Linear Quadratic Regulator (LQR) is developed, in which the LQR weighting matrices are adjusted online based on a grey relational grade that synthesizes vibration attenuation, control energy, and robustness metrics. A finite-element model incorporating piezoelectric actuator–sensor coupling is used to generate a hypothetical modal-test dataset, and both numerical simulations and laboratory experiments on an aluminium cantilever beam validate the method. Simulation results show up to 25 % and 13.6 % improvements in vibration attenuation over deterministic and genetic-algorithm-tuned LQR, respectively, while reducing control energy by 12.5 %. Experimental trials confirm 29.7 % and 14.3 % attenuation gains, 15.3 % energy savings, and a 41.7 % enhancement in robustness under ± 10 % parameter variations. Environmental robustness tests demonstrate only a 2.1 % performance drop under a 20 °C temperature increase, compared to an 8.1 % drop for conventional tuning. One-way ANOVA confirms that the observed improvements are highly significant (F ≫ F₍₂,₁₂,₀.₀₅₎). The proposed Fuzzy–GRA approach thus offers a mathematically rigorous yet practical strategy for tuning AVC gains under uncertainty, with promising applications in structural health monitoring and precision engineering.

Open Access

Article

Article ID: 3343

Why pile-soil interaction matters: dynamic characteristics and vibration suppression in large offshore wind turbines

by Yang Xue , Linan Li, Jia Han, Huixin Wei, Shibin Wang, Haikun Jia, Lingxing Kong

Sound & Vibration, Vol.59, No.4, 2025;

In the complex marine environment characterized by wind, waves and soils, the dynamic behavior of offshore wind turbines (OWTs) is highly intricate due to the coupled interactions among various components. However, current research often neglects soil-pile interaction. This study develops a dynamic analytical model of the entire OWT system incorporating soil-pile interaction based on the Euler-Lagrange equations. Wind, wave and soil loads are respectively calculated using blade element momentum theory, Morison’s equation and p−y curves. The dynamic responses of structural components, including blades, tower and monopile, under combined wind-wave-soil loads are then evaluated. A comparative analysis is conducted to examine the effects of soil-pile interaction and varying damping ratios on the frequency response of a 22-MW OWT. Results indicate that considering the monopile support structure and ignoring soil-pile interaction significantly underestimates the soil’s contribution to structural stiffness and equivalent damping. For example, Fourier amplitude spectra curves reveal that soil-pile interaction shifts the dominant frequency and reduces peak displacements by over 30%. This refined methodology enables a more physically consistent representation of soil-pile interaction dynamics by explicitly incorporating the nonlinear behavior at the pile-soil interface. The enhanced framework effectively captures critical phenomena such as soil-induced frequency shifts and damping-mediated amplitude attenuation, which are essential for accurate resonance avoidance and fatigue life estimation in practical engineering applications.

Open Access

Article

Article ID: 3449

Ways to compensate poor acoustic characteristics of classrooms

by Viktor Sebestyén, Dóra Szeles, Endre Domokos

Sound & Vibration, Vol.59, No.4, 2025;

The acoustic conditions of classrooms play an important role in the performance of students, especially in the acquisition of foreign languages, but at the same time, the design of classrooms according to acoustic aspects is not a proven practice, so exploring the possibilities of subsequent compensation for classrooms in inadequate condition is an important task in order to ensure quality education. In this research, technical and organizational solutions will be comprehensively examined to improve speech intelligibility in the examined primary school and university classrooms, which will be carried out by the measurement and modelling of the Speech Transmission Index (STI). We developed seven compensation scenarios and a baseline scenario for acoustic development, which are also compared from a cost-effectiveness point of view. The insulation of the back wall, the creation of an insulating false ceiling, their combined implementation, the modernization of the windows, the effect of teacher’s position, the opened windows, and the increased volume are examined. The results of the research can be used in all institutions where acoustic compensation is needed, providing useful results not only for room acoustics specialists but also for institutional decision-makers and teachers. The measurement results show that in classrooms in quiet environments, in addition to technical solutions, which can be applied in all cases, organizational solutions can also be effective.

Open Access

Review

Article ID: 3723

Research progress on insertion loss measurement and effective sound pressure level prediction models of hearing protectors under high-intensity impulse noise

by Yuanyuan Song, Zhuowei Chen

Sound & Vibration, Vol.59, No.4, 2025;

Impulse noise, characterized by extremely high peak levels, rapid rise times, and very short durations, poses a far greater risk to hearing than continuous noise of comparable energy. Conventional assessment methods developed for steady-state exposures often underestimate the hazard of such impulses, creating a need for models and measurement approaches that accurately predict effective sound pressure levels behind hearing protectors. This review synthesizes current knowledge on impulse noise characteristics, laboratory and field measurement techniques, and prediction models designed for hearing protector evaluation. Evidence indicates that energy-equivalent metrics such as A-weighted equivalent levels are insufficient for impulse conditions. Parametric models that include peak level and duration, frequency-dependent approaches that emphasize spectral distribution and waveform statistics, and biophysical algorithms that simulate auditory responses offer progressively greater predictive accuracy. Recent hybrid frameworks, supported by computational modelling, machine learning, and wearable dosimetry, represent promising directions for integrating laboratory precision with field relevance. When applied to hearing protectors, prediction models reveal both their strengths and limitations. Laboratory studies confirm substantial attenuation under controlled conditions, but nonlinear protector behaviour and fit variability reduce reliability in real-world use. Field data demonstrate that cumulative and waveform-sensitive metrics align more closely with observed auditory outcomes than peak-only criteria. The findings underscore the importance of developing harmonized standards and adopting advanced prediction frameworks. Such progress is essential for improving hearing conservation strategies in military, industrial, and other high-risk environments.