Vibration

21 pages, 4047 KB

Open AccessArticle

Natural Frequency and Damping Characterisation of Aerospace Grade Composite Plates

by Rade Vignjevic, Nenad Djordjevic, Javier de Caceres Prieto, Nenad Filipovic, Milos Jovicic and Gordana Jovicic

Vibration 2025, 8(4), 72; https://doi.org/10.3390/vibration8040072 (registering DOI) - 13 Nov 2025

Abstract

The natural frequencies and damping characterisation of a new aerospace grade composite material were investigated using a modified impulse method combined with the half power bandwidth method, which is applicable to the structures with a low damping. The composite material of interest was [...] Read more.

The natural frequencies and damping characterisation of a new aerospace grade composite material were investigated using a modified impulse method combined with the half power bandwidth method, which is applicable to the structures with a low damping. The composite material of interest was unidirectional carbon fibre reinforced plastic. The tests were carried out with three identical square 4.6 mm thick plates consisting of 24 plies. The composite plates were clamped along one edge in a SignalForce shaker, which applied a sinusoidal signal generated by the signal conditioner exiting the bending modes of the plates. Laser vibrometer measurements were taken at three points on the free end so that different vibrational modes could be obtained: one measurement was taken on the longitudinal symmetry plane with the other two 35 mm on either side of the symmetry plane. The acceleration of the clamp was also recorded and integrated twice to calculate its displacement, which was then subtracted from the free end displacement. Two material orientations were tested, and the first four natural frequencies were obtained in the test. Damping was determined by the half-power bandwidth method. A linear relationship between the loss factors and frequency was observed for the first two modes but not for the other two modes, which may be related to the coupling of the modes of the plate and the shaker. The experiment was also modelled by using the Finite Element Method (FEM) and implicit solver of LS Dyna, where the simulation results for the first two modes were within 15% of the experimental results. The novelty of this paper lies in the presentation of new experimental data for the natural frequencies and damping coefficients of a newly developed composite material intended for the vibration analysis of rotating components. Full article

► Show Figures

Figure 1

16 pages, 26757 KB

Open AccessArticle

Time–Frequency Analysis of Railway Bridges Forced and Free Vibrations Identified by Wavelet Transform

by Pedro Galvín, Antonio Romero, Mario Solís, Emma Moliner and María Dolores Martínez-Rodrigo

Vibration 2025, 8(4), 71; https://doi.org/10.3390/vibration8040071 - 6 Nov 2025

Viewed by 205

Abstract

In this work, a time–frequency analysis of two railway bridges included in the InBridge4EU project database is presented. The study focuses on the identification of modal parameters from free responses after train passages and their comparison with estimations obtained from ambient vibration data. [...] Read more.

In this work, a time–frequency analysis of two railway bridges included in the InBridge4EU project database is presented. The study focuses on the identification of modal parameters from free responses after train passages and their comparison with estimations obtained from ambient vibration data. The wavelet transform is introduced as a valuable tool for detecting both free and forced bridge responses due to different train passages, as well as for conducting time–frequency analysis. This approach is particularly relevant for the identification of structural damping, given its dependence on vibration amplitude, as it enables the estimation of realistic values representative of bridge behavior under operational conditions. Additionally, the paper examines the complementary use of free vibrations for identifying natural frequencies and comparing them with results from ambient vibration tests. Wavelet analysis further reveals the predominant frequencies in the structural response before, during, and after train crossings, thereby capturing the influence of the moving vehicle on bridge dynamics. Full article

(This article belongs to the Special Issue Railway Dynamics and Ground-Borne Vibrations)

► Show Figures

Figure 1

28 pages, 6285 KB

Open AccessArticle

Prediction of Construction-Induced Ground Vibrations Using Field Measurements and Bidirectional Gated Recurrent Unit Neural Network

by Reza Rafiee-Dehkharghani, Kamran Esmaeili and Meysam Najari

Vibration 2025, 8(4), 70; https://doi.org/10.3390/vibration8040070 - 6 Nov 2025

Viewed by 189

Abstract

This paper proposes a sequential bidirectional gated recurrent unit (BGRU) model to predict construction-induced ground vibrations. The ground vibration time histories for twelve real construction projects in Toronto, Canada, are collected and used to develop the BGRU model. A single time-step method is [...] Read more.

This paper proposes a sequential bidirectional gated recurrent unit (BGRU) model to predict construction-induced ground vibrations. The ground vibration time histories for twelve real construction projects in Toronto, Canada, are collected and used to develop the BGRU model. A single time-step method is used to predict the vibrations, and the time window is swept continuously over the whole training data. In addition to the BGRU method, and for comparison, two other methods, autoregressive integrated moving average (ARIMA) and random forest (RF), are used to predict the ground vibrations. The results show that the BGRU method performs much better than ARIMA and RF methods in forecasting construction-induced ground vibrations. The BGRU method captures the construction-induced and background vibrations very well, and this method remains accurate when the training data includes both background and construction vibrations. Therefore, this method can be used to predict ground vibrations in real projects where there is always a potential for missing some parts of the ground vibration data due to the malfunction of the vibration recording units. Full article

► Show Figures

Figure 1

24 pages, 7890 KB

Open AccessArticle

A Novel Rapid Detection Method for Bridge Vibration Based on an Unmanned Aerial Vehicle and a Raspberry Pi

by Liang Huang, Kang Li, Jinke Li, Panjie Li, Can Cui and Pengfei Zheng

Vibration 2025, 8(4), 69; https://doi.org/10.3390/vibration8040069 - 5 Nov 2025

Viewed by 297

Abstract

The high cost of traditional structural health monitoring systems limits their application to only a few major bridges, leaving most structures unmonitored between manual inspections. To address this issue, this study proposes a UAV mobile detection device (UMD) system that integrates a Raspberry [...] Read more.

The high cost of traditional structural health monitoring systems limits their application to only a few major bridges, leaving most structures unmonitored between manual inspections. To address this issue, this study proposes a UAV mobile detection device (UMD) system that integrates a Raspberry Pi, data acquisition module, and accelerometer for rapid, contact-based vibration measurement. A vibration transmission model between the UMD and the bridge deck is developed to guide hardware design and quantify the influence of isolator stiffness and damping. The UMD’s performance is validated through both laboratory floor tests and field bridge experiments, demonstrating reliable identification of modal frequencies in the range of 0.00–51.95 Hz with a maximum acceleration error below 0.01 g and a relative modal frequency deviation within 3.4%. The analysis further determines that an accelerometer resolution of

0.02 \times 10^{- 1}

g is required for accurate frequency domain measurement. These findings establish the UMD as a fast, low-cost, and accurate tool for rapid bridge vibration assessment and lay the groundwork for future multi-UAV synchronized monitoring. Full article

► Show Figures

Figure 1

28 pages, 695 KB

Open AccessReview

Recent Advances in Vibration Analysis for Predictive Maintenance of Modern Automotive Powertrains

by Rajesh Shah, Vikram Mittal and Michael Lotwin

Vibration 2025, 8(4), 68; https://doi.org/10.3390/vibration8040068 - 3 Nov 2025

Viewed by 716

Abstract

Vibration-based predictive maintenance is an essential element of reliability engineering for modern automotive powertrains including internal combustion engines, hybrids, and battery-electric platforms. This review synthesizes advances in sensing, signal processing, and artificial intelligence that convert raw vibration into diagnostics and prognostics. It characterizes [...] Read more.

Vibration-based predictive maintenance is an essential element of reliability engineering for modern automotive powertrains including internal combustion engines, hybrids, and battery-electric platforms. This review synthesizes advances in sensing, signal processing, and artificial intelligence that convert raw vibration into diagnostics and prognostics. It characterizes vibration signatures unique to engines, transmissions, e-axles, and power electronics, emphasizing order analysis, demodulation, and time–frequency methods that extract weak, non-stationary fault content under real driving conditions. It surveys data acquisition, piezoelectric and MEMS accelerometry, edge-resident preprocessing, and fleet telemetry, and details feature engineering pipelines with classical machine learning and deep architectures for fault detection and remaining useful life prediction. In contrast to earlier reviews focused mainly on stationary industrial systems, this review unifies vibration analysis across combustion, hybrid, and electric vehicles and connects physics-based preprocessing to scalable edge and cloud implementations. Case studies show that this integrated perspective enables practical deployment, where physics-guided preprocessing with lightweight models supports robust on-vehicle inference, while cloud-based learning provides cross-fleet generalization and model governance. Open challenges include disentangling overlapping sources in compact e-axles, coping with domain and concept drift from duty cycles, software updates, and aging, addressing data scarcity through augmentation, transfer, and few-shot learning, integrating digital twins and multimodal fusion of vibration, current, thermal, and acoustic data, and deploying scalable cloud and edge AI with transparent governance. By emphasizing inverter-aware analysis, drift management, and benchmark standardization, this review uniquely positions vibration-based predictive maintenance as a foundation for next-generation vehicle reliability. Full article

► Show Figures

Figure 1

15 pages, 3627 KB

Open AccessArticle

Experimental Investigation of Ring-Type Resonator Dynamics

by Ali F. Abdulla, Soroush Arghavan, Jihyun Cho, Ibrahim F. Gebrel, Mohamed Bognash and Samuel F. Asokanthan

Vibration 2025, 8(4), 67; https://doi.org/10.3390/vibration8040067 - 28 Oct 2025

Viewed by 262

Abstract

One of the challenges in inertia sensor applications is the need for a class of devices that operate at one of the ring resonant frequencies to achieve large amplitudes of vibration. However, large amplitudes tend to produce undesirable nonlinear effects due to geometrical [...] Read more.

One of the challenges in inertia sensor applications is the need for a class of devices that operate at one of the ring resonant frequencies to achieve large amplitudes of vibration. However, large amplitudes tend to produce undesirable nonlinear effects due to geometrical nonlinearities. Hence, a rigorous experimental dynamic analysis of rotating thin circular ring-type structures is considered important to gain a deeper understanding of the device’s nonlinear behavior as well as the potential performance improvements. This study aims to experimentally investigate the nonlinear dynamic behavior of rotating thin circular rings and the effects of angular rate as well as mass mismatch variations on the system natural frequency. A prototype made of a macroscale thin cylindrical structure is employed to study the nonlinear dynamic behavior of rotating thin circular rings. Using a precision rate table equipped with a slip ring as well as non-contact sensors/actuators, experiments that closely represent the actual physical operating conditions of angular rate sensors are developed. Natural frequency variations due to the input angular rate changes are measured in time and frequency domains. Useful experimental observations on the frequency split and mass mismatch effects have been performed. Typical nonlinear behavior, such as jump phenomena of a rotating thin circular cylinder, is noted. The nonlinear dynamic behavior of a ring-type resonator system, which is subjected to external excitations, is experimentally investigated. Results from the present experimental study on the mechanics of the ring structure are expected to provide further insight into the design and operation of ring-type resonators for angular rate sensing applications. Full article

► Show Figures

Figure 1

11 pages, 413 KB

Open AccessArticle

A Study on Nonlinear Vibrations in the Impact-Echo Method for Void Flaw Detection in Solids

by Denyue Sun, Yousef Sardahi, Gang S. Chen, Wael Zatar, Hien Nghiem and Zhaohui (Joey) Yang

Vibration 2025, 8(4), 66; https://doi.org/10.3390/vibration8040066 - 20 Oct 2025

Viewed by 364

Abstract

This paper presents a study on the nonlinear vibrations in the impact-echo (IE) method for void flaw detection of solid structures. Linear theory has historically served as the foundational framework for non-destructive methods, including the IE method, particularly for estimating flaws in solids. [...] Read more.

This paper presents a study on the nonlinear vibrations in the impact-echo (IE) method for void flaw detection of solid structures. Linear theory has historically served as the foundational framework for non-destructive methods, including the IE method, particularly for estimating flaws in solids. This paper gives a comprehensive analysis of the nonlinear theory behind the IE method for detection of voids in solids such as concrete structures. The general equation of motion is presented for the flexural vibration of a void-defected solid with general nonlinear constitutive material properties, and then the simplified solutions for polynomial nonlinearity and hysteresis nonlinearity are derived comprehensively. The solutions of principal frequency and sub- and super-harmonics as well as the frequency of combined modes are elaborated, and the theoretical formula of resonant frequency shift with amplitude is derived. As conventional nonlinear IE methods have been conducted by only using a phenomenological model of linear shift in resonant frequency with amplitude, the proposed new frame of nonlinear vibration theory can be used to implement the IE method more comprehensively and accurately for void detection in solids. Full article

► Show Figures

Figure 1

31 pages, 13164 KB

Open AccessArticle

Transfer Learning Approach for Estimating Modal Parameters of Robot Manipulators Using Minimal Experimental Data

by Seyed Hamed Seyed Hosseini, Seyedhossein Hajzargarbashi, Gabriel Côté and Zhaoheng Liu

Vibration 2025, 8(4), 65; https://doi.org/10.3390/vibration8040065 - 18 Oct 2025

Viewed by 315

Abstract

Robots are used more and more in manufacturing, especially in tasks like robotic machining, where understanding their vibration behavior is very important. However, robot vibrations vary with posture, and evaluating all representative postures requires significant time and cost. This study proposes a deep [...] Read more.

Robots are used more and more in manufacturing, especially in tasks like robotic machining, where understanding their vibration behavior is very important. However, robot vibrations vary with posture, and evaluating all representative postures requires significant time and cost. This study proposes a deep learning (DL) based transfer learning (TL) approach to predict robot vibration behavior using fewer experiments. A large dataset was collected from a KUKA KR300 robot (Robot A) by testing nearly 250 postures. This dataset was then used to train a model to predict modal parameters such as natural frequencies (ω_n), damping ratios (ξ), and modal stiffness (k) within the workspace. TL was then used to apply the knowledge from Robot A to two other robots: a Comau NJ 650-2.7 (Robot B, high-payload) and an ABB IRB 4400 (Robot C, low-payload). Only a small number of postures were tested for Robots B and C. They were chosen carefully to cover different workspace areas and avoid collisions. Hammer tests were performed, and a four-step process was used to identify the real vibration modes. Stabilization diagrams were applied to confirm valid modes and remove noise. The results show that TL can accurately predict modal parameters for both Robot B and Robot C, even with limited data. These predictions were also used to estimate frequency response functions (FRFs), which matched well with experimental results. The main novelties of this work are: achieving accurate prediction of posture-dependent dynamics using minimal experimental data, demonstrating generalization across robots with different payload capacities, and revealing that data coverage across the workspace is more critical than dataset size. Full article

► Show Figures

Figure 1

20 pages, 1650 KB

Open AccessArticle

Power-Based Statistical Detection of Substance Accumulation in Constrained Places Using a Contact-Less Passive Magnetoelastic Sensor

by Ioannis Kalyvas and Dimitrios Dimogianopoulos

Vibration 2025, 8(4), 64; https://doi.org/10.3390/vibration8040064 - 10 Oct 2025

Viewed by 404

Abstract

A contactless passive magnetoelastic sensing setup, recently proposed for detecting pest/substance accumulation in confined spaces (labs, museum reserves), is optimized for enhanced low-frequency performance. The setup uses a short flexible polymer slab, clamped at one end. There, a short Metglas^® 2826MB magnetoelastic [...] Read more.

A contactless passive magnetoelastic sensing setup, recently proposed for detecting pest/substance accumulation in confined spaces (labs, museum reserves), is optimized for enhanced low-frequency performance. The setup uses a short flexible polymer slab, clamped at one end. There, a short Metglas^® 2826MB magnetoelastic ribbon is fixed upon the slab’s surface. The opposite end receives excitation by a remotely controlled module of ultra-low amplitude vibration. When vibrating (with the slab), the ribbon generates magnetic flux, which depends on (and reflects) the slab’s dynamics. This changes when loads accumulate on its surface. The flux induces voltage in a contactless manner in a low-cost pick-up coil suspended above the ribbon. Voltage monitoring allows for evaluation of the vibrating slab’s real-time dynamics and, consequently, the detection of load-induced changes. This work innovates by introducing a low-cost passive circuit for real-time voltage processing, thus achieving an accurate representation of the low-frequency dynamics of the magnetic flux. Furthermore, it introduces an algorithm, which statistically detects load-induced changes using the voltage’s low-frequency power characteristics. Both additions enable load detection at relatively low frequencies, thus addressing a principal issue of passive contactless sensing setups. Extensive testing at different occasions demonstrates promising load detection performance under various conditions, especially given its cost-efficient hardware and operation. Full article

► Show Figures

Figure 1

15 pages, 429 KB

Open AccessReview

Guide to the Effects of Vibration on Health—Quantitative or Qualitative Occupational Health and Safety Prevention Guidance? A Scoping Review

by Eckardt Johanning and Alice Turcot

Vibration 2025, 8(4), 63; https://doi.org/10.3390/vibration8040063 - 6 Oct 2025

Viewed by 1145

Abstract

This systematic review examined the health risk assessment methods of studies of whole-body vibration exposure from occupational vehicles or machines utilizing the International Standard ISO 2631-1 (1997) and/or the European Machine Directive 2002/44. This review found inconsistent reporting of measurement parameters in studies [...] Read more.

This systematic review examined the health risk assessment methods of studies of whole-body vibration exposure from occupational vehicles or machines utilizing the International Standard ISO 2631-1 (1997) and/or the European Machine Directive 2002/44. This review found inconsistent reporting of measurement parameters in studies on whole-body vibration (WBV) exposure. Although many authors treat the ISO 2631-1 HGCZ as a medical health standard with defined threshold levels, the epidemiological evidence for these limits is unclear. Similarly, the EU Directive offers more comprehensive risk management guidance, but the numeric limits are equal without supporting scientific evidence. Both guidelines likely represent the prevailing societal and interdisciplinary consensus at the time. Authors note discrepancies between international and national standards and adverse WBV exposure outcomes are reported below given boundaries. Future publications should report all relevant parameters from ISO 2631-1 and clearly state study limitations, exercising caution when applying ISO 2631-1 HGCZ in health and safety assessments and considering different susceptibility of diverse populations. We advise reducing WBV exposure to the lowest technically feasible limits wherever possible and applying the precautionary principle with attention to individual differences, instead of depending solely on numeric limits. Full article

(This article belongs to the Special Issue Whole-Body Vibration and Hand-Arm Vibration Related to ISO-TC108-SC4 Published Standards)

► Show Figures

Figure 1

15 pages, 7276 KB

Open AccessArticle

Effectiveness of Dynamic Vibration Absorber on Ground-Borne Vibration Induced by Metro

by Javad Sadeghi, Alireza Toloukian and Sogand Mehravar

Vibration 2025, 8(4), 62; https://doi.org/10.3390/vibration8040062 - 5 Oct 2025

Viewed by 450

Abstract

The application of dynamic vibration absorbers (DVAs) is a countermeasure to suppress vibrations induced by railway traffic. A key advantage of the DVA application is that it does not require any changes to the path of vibration propagation or the receiver of vibration. [...] Read more.

The application of dynamic vibration absorbers (DVAs) is a countermeasure to suppress vibrations induced by railway traffic. A key advantage of the DVA application is that it does not require any changes to the path of vibration propagation or the receiver of vibration. A review of the literature reveals the necessity of deriving the optimum properties of DVA to mitigate railway vibrations. To this end, the optimum DVA properties were investigated through the development of a two-dimensional finite element model of the track-tunnel-soil system. The model was validated using the results of a field test. A parametric study was made to obtain the optimum properties of DVA for different soils surrounding the tunnel. The results of the model analysis indicate that the DVA has better vibration reduction for metro tunnels built in soft soils as compared to those surrounded by medium and stiff soils. Also, the results disclose that the DVA reduces vibration radiated on the ground surface when the DVA natural frequency is tuned to a low frequency. Using the results of the parametric study, graphs are suggested to select the optimum properties of the DVA as a function of the soil around the tunnel. Full article

(This article belongs to the Special Issue Railway Dynamics and Ground-Borne Vibrations)

► Show Figures

Figure 1

12 pages, 776 KB

Open AccessArticle

Mounted Accelerometer Frequency Response of Adhesive Products and Aluminum Frame Quick Mounts

by Kenton Hummel, Jay Hix and Edna Cárdenas

Vibration 2025, 8(4), 61; https://doi.org/10.3390/vibration8040061 - 3 Oct 2025

Viewed by 635

Abstract

An accelerometer mounting technique has large implications on the frequency range and accuracy of the measurement, with stiffness and the mass relative to the monitored structure as the primary concerns. The International Organization for Standardization (ISO) gives an extensive list in 5348:2021, detailing [...] Read more.

An accelerometer mounting technique has large implications on the frequency range and accuracy of the measurement, with stiffness and the mass relative to the monitored structure as the primary concerns. The International Organization for Standardization (ISO) gives an extensive list in 5348:2021, detailing mounting methods, and provides recommendations for testing mounts that are not specifically defined. In the nuclear industry on the laboratory scale, there is a need for vibration measurements for predictive maintenance and process monitoring that are nondestructive and capable of working in high-temperature environments. Commercial adhesive products with easy application and removal were tested as nondestructive methods, while quick mounts to a commonly used aluminum frame were tested as nondestructive and have potential applicability in high-temperature environments. The sinusoidal excitation method was used, measuring frequencies from 50 Hz to 10 kHz in one-third octave band intervals, utilizing three accelerometers and comparing the results to those obtained with the stud-mounting method. Using the lowest ±3 dB threshold across each accelerometer, foam dots and poster strips were not successful, and foam tapes were accurate up to 2000 Hz, hose clamps and zip ties up to 800 Hz, and a custom 3D printed mount up to 1000 Hz. Knowing the limitations of each mounting technique allows for accurate measurements within the appropriate range. Full article

► Show Figures

Figure 1

21 pages, 2866 KB

Open AccessArticle

Evaluation of the Adaptive Behavior of a Shell-Type Elastic Element of a Drilling Shock Absorber with Increasing External Load Amplitude

by Andrii Velychkovych, Vasyl Mykhailiuk and Andriy Andrusyak

Vibration 2025, 8(4), 60; https://doi.org/10.3390/vibration8040060 - 2 Oct 2025

Cited by 1 | Viewed by 451

Abstract

Vibration loads during deep drilling are one of the main causes of reduced service life of drilling tools and emergency failure of downhole motors. This work investigates the adaptive operation of an original elastic element based on an open cylindrical shell used as [...] Read more.

Vibration loads during deep drilling are one of the main causes of reduced service life of drilling tools and emergency failure of downhole motors. This work investigates the adaptive operation of an original elastic element based on an open cylindrical shell used as part of a drilling shock absorber. The vibration protection device contains an adjustable radial clearance between the load-bearing shell and the rigid housing, which provides the effect of structural nonlinearity. This allows effective combination of two operating modes of the drilling shock absorber: normal mode, when the clearance does not close and the elastic element operates with increased compliance; and emergency mode, when the clearance closes and gradual load redistribution and increase in device stiffness occur. A nonconservative problem concerning the contact interaction of an elastic filler with a coaxially installed shaft and an open shell is formulated, and as the load increases, contact between the shell and the housing, installed with a radial clearance, is taken into account. Numerical finite element modeling is performed considering dry friction in contact pairs. The distributions of radial displacements, contact stresses, and equivalent stresses are examined, and deformation diagrams are presented for two loading modes. The influence of different cycle asymmetry coefficients on the formation of hysteresis loops and energy dissipation is analyzed. It is shown that with increasing load, clearance closure begins from local sectors and gradually covers almost the entire outer surface of the shell. This results in deconcentration of contact pressure between the shell and housing and reduction of peak concentrations of equivalent stresses in the open shell. The results confirm the effectiveness of the adaptive approach to designing shell shock absorbers capable of reliably withstanding emergency overloads, which is important for deep drilling where the exact range of external impacts is difficult to predict. Full article

(This article belongs to the Special Issue Vibration Damping)

► Show Figures

Figure 1

13 pages, 3175 KB

Open AccessArticle

Enhancement of Inner Race Fault Features in Servo Motor Bearings via Servo Motor Encoder Signals

by Yubo Lyu, Yu Guo, Jiangbo Li and Haipeng Wang

Vibration 2025, 8(4), 59; https://doi.org/10.3390/vibration8040059 - 1 Oct 2025

Viewed by 342

Abstract

This study proposes a novel framework to enhance inner race fault features in servo motor bearings by acquiring rotary encoder-derived instantaneous angular speed (IAS) signals, which are obtained from a servo motor encoder without requiring additional external sensors. However, such signals are often [...] Read more.

This study proposes a novel framework to enhance inner race fault features in servo motor bearings by acquiring rotary encoder-derived instantaneous angular speed (IAS) signals, which are obtained from a servo motor encoder without requiring additional external sensors. However, such signals are often obscured by strong periodic interferences from motor pole-pair and shaft rotation order components. To address this issue, three key improvements are introduced within the cyclic blind deconvolution (CYCBD) framework: (1) a comb-notch filtering strategy based on rotation domain synchronous averaging (RDA) to suppress dominant periodic interferences; (2) an adaptive fault order estimation method using the autocorrelation of the squared envelope spectrum (SES) for robust localization of the true fault modulation order; and (3) an improved envelope harmonic product (IEHP), based on the geometric mean of harmonics, which optimizes the deconvolution filter length. These combined enhancements enable the proposed improved CYCBD (ICYCBD) method to accurately extract weak fault-induced cyclic impulses under complex interference conditions. Experimental validation on a test rig demonstrates the effectiveness of the approach in enhancing and extracting the fault-related features associated with the inner race defect. Full article

(This article belongs to the Special Issue Vibration in 2025)

► Show Figures

Figure 1

23 pages, 3652 KB

Open AccessArticle

Vibration Control of a Two-Link Manipulator Using a Reduced Model

by Amir Mohamad Kamalirad and Reza Fotouhi

Vibration 2025, 8(4), 58; https://doi.org/10.3390/vibration8040058 - 1 Oct 2025

Viewed by 357

Abstract

This research aims to actively suppress vibrations at the end-effector of a flexible manipulator. When configured in a locked state, the system behaves as a two-link manipulator subjected to disturbances on the first link. To analyze its behavior, Finite Element Analysis (FEA) is [...] Read more.

This research aims to actively suppress vibrations at the end-effector of a flexible manipulator. When configured in a locked state, the system behaves as a two-link manipulator subjected to disturbances on the first link. To analyze its behavior, Finite Element Analysis (FEA) is employed to extract the natural frequencies (eigenvalues) and corresponding mode shapes (eigenvectors) of a two-link, two-joint flexible manipulator (2L2JM). The obtained eigenvectors are transformed into uncoupled state-space equations using balanced realization and the Match-DC-Gain model reduction algorithm. An H-infinity controller is then designed and applied to both the full-order and reduced-order models of the manipulator. The objective of this study is to validate an analytical framework through FEA, demonstrating its applicability to complex manipulators with multiple joints and flexible links. Given that the full state-space representation typically results in high-dimensional matrices, model reduction enables effective vibration control with a minimal number of states. The derivation of the 2L2JM state space, its model reduction, and a subsequent control strategy have not been previously addressed in this manner. Simulation results showcasing vibration suppression of a cantilever beam are presented and benchmarked against two alternative modeling approaches. Full article

► Show Figures

Figure 1

22 pages, 12270 KB

Open AccessArticle

Influence of Random Parametric Errors on Nonlinear Dynamic Behaviors of a Laminated Composite Cantilever Beam

by Lin Sun, Xudong Li and Xiaopei Liu

Vibration 2025, 8(4), 57; https://doi.org/10.3390/vibration8040057 - 29 Sep 2025

Viewed by 256

Abstract

For the first time, the influence of random parametric errors (RPEs) on the nonlinear dynamic behaviors of a laminated composite cantilever beam (LCCB) is studied. A nonlinear dynamic model for the LCCB is first established based on Hamilton’s principle. In a numerical simulation, [...] Read more.

For the first time, the influence of random parametric errors (RPEs) on the nonlinear dynamic behaviors of a laminated composite cantilever beam (LCCB) is studied. A nonlinear dynamic model for the LCCB is first established based on Hamilton’s principle. In a numerical simulation, four different cases are presented to analyze the dynamic behavior of the studied LCCB. This study reveals that varying RPE levels cause significant changes in the dynamic response of the LCCB. The results indicate that RPE not only induces a transition from a periodic to a chaotic behavior but may also alter the maximum amplitude of chaotic vibrations, providing a critical theoretical basis for incorporating uncertainty factors in engineering design. Full article

► Show Figures

Figure 1

34 pages, 16346 KB

Open AccessReview

A Review on Vibration Sensor: Key Parameters, Fundamental Principles, and Recent Progress on Industrial Monitoring Applications

by Limin Ma, Zhangpeng Li, Shengrong Yang and Jinqing Wang

Vibration 2025, 8(4), 56; https://doi.org/10.3390/vibration8040056 - 25 Sep 2025

Viewed by 3781

Abstract

This paper presents a systematic review of vibration sensors and their application in industrial-monitoring systems, aiming to provide a comprehensive reference for both academic research and practical applications in this field. Through the classification of measured parameters and sensing principles, this work endeavors [...] Read more.

This paper presents a systematic review of vibration sensors and their application in industrial-monitoring systems, aiming to provide a comprehensive reference for both academic research and practical applications in this field. Through the classification of measured parameters and sensing principles, this work endeavors to establish a structured understanding of vibration sensor’s working mechanism and deliver an in-depth analysis of their recent research achievements. By integrating practical cases from typical domains, this manuscript comprehensively demonstrates the practical value and application potential of vibration sensors in equipment-monitoring systems, illustrating how these sensors are utilized to detect mechanical failures and enhance the performance and safety of industrial systems, such as wind turbine, tunnel boring machine, and aerospace engine. Looking forward, with the rapid advancement of the Internet of Things (IoT) and artificial intelligence (AI) technologies, vibration sensors are anticipated to evolve towards multifunctionalization, miniaturization and intelligentization, thereby forming a comprehensive monitoring network that improves overall efficiency and reliability of the mechanical systems. Full article

► Show Figures

Figure 1

Journal Menu

Journal Browser

Vibration, Volume 8, Issue 4 (December 2025) – 17 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI