A novel robust edge detection method is developed for an image-based tracking continuously scanning laser Doppler vibrometer (CSLDV) system to track a rotating structure without attaching any encoder or mark to it and scan its whole surface. The robust edge detection method can extract edges of the rotating structure from its complex background by processing grayscale images of the rotating structure

Continuous monitoring and in particular structural health monitoring (SHM) of structures is used, nowadays, by asset managers to ensure a high level of safety and extend the lifetime of their assets. One of the main bottlenecks faced in the development of an SHM system is the design and implementation of sensor networks. This includes selecting the sensor type and optimizing the number and positions

Various operational modal analysis (OMA) methods have been developed to identify the modal parameters of buildings in use. Recently, efforts have been expended to solve the existing problems associated with accuracy and computational time of OMA methods using deep learning algorithms of convolution neural network (CNN) and deep neural network (DNN). Considering that the result of modal parameters involves

Multi-input multi-output random vibration control combined with limit channels is a commonly used experiment scheme in dynamic environmental testing. This paper proposes a limit control strategy for multi-shaker random vibration tests. Compared to the traditional limit control method, the presented work can alleviate the undertesting phenomenon. The fundamental principles and difficulties in limit

Resonance can be avoided by preventing the structural natural frequencies from falling within the operating frequency range. However, structural natural frequencies are influenced by uncertain parameters, such as material properties and geometric sizes. Therefore, it is essential to consider these uncertainties during the conceptual design phase. To address this problem, a novel reliability-based eigenvalue

The identification of nonlinearities that have a significant impact on dynamic behaviour of complex mechanical structures is necessary for ensuring structural efficiency and safety. A new methodology for structural identification of nonlinear assemblies is proposed in this paper that enables the discovery of stiffness and damping nonlinear models especially when it is not possible to directly measure

Neural network-based strategies require balanced training datasets to avoid creating unreliable classification and prediction models. While these strategies are commonly used to model the dynamics of structural and mechanical systems, the imbalanced composition of monitoring data is a fundamental challenge for damage assessment in structural systems. The monitoring data often contain abundant observations

The bistable asymmetric composite laminated structures have the broad applications in the design of the deformable aircrafts and energy harvester due to the unique nonlinear dynamic snap-through characteristics. This paper studies the dynamic snap-through phenomena and nonlinear vibrations of the bistable asymmetric cross-ply composite laminated cantilever shell under the external excitation. Reddy’s

Composite materials, regarding their lightweight, can be considered a suitable option for the next generation of piezoelectric energy harvesters, which are used for supporting low-power applications. Also, due to the broader selection range and different stacking sequences, one of the advantages of these materials is that they can provide better stiffness adjustment of the structure to achieve the

Blisks undergoing blade repairs by the ‘blending’ technique, require structural analyses to assess possible dynamic issues and also to define the blend repair limits, etc. This usually leads to prohibitive computational costs due to the large-scale full-order industrial blisk finite element models. This paper presents a novel model reduction approach, termed ‘Sector Mode Assembling Reduction Technique’

Aiming at the problem that the dynamic displacement at critical positions of the cable cannot be measured due to economic or difficult installation, this paper proposes a method to invert the dynamic displacement of the cable in the whole field by using the dynamic displacement of a single measuring point. The method can realize the inversion of the lateral dynamic displacement response (L-DDR) and

Data driven methods for impact location and severity estimation have great potential for real life application due to their ability to construct meta models that are not affected by changes in structural complexity (e.g. stiffeners and cut-outs). However, to do so, an initial reference database containing known input and output pairs is required to form an accurate meta model. The requirement to collect

Accurate remaining useful life prediction (RUL) is important for the reliability and safety of liquid rocket engines. In this paper, a meta network pruning framework with attention augmented convolutions is proposed for RUL prediction. To address the problem of distribution discrepancy in engineering data under transient working conditions, a data-driven distribution matching strategy is designed.

In order to be used in the CNC machining center, one rotary ultrasonic machining (RUM) system needs to adapt to various cutting tools. Corresponding ultrasonic vibration units are often designed to work in a local resonant state rather than a full resonant state due to the diversity and complexity of tool shapes. Since the frequency at which the vibration of various cutting tools reaches the maximum

Alternative Tuned Mass Damper (TMD) configurations have been proposed in the literature for performance improvement and maintenance, mainly modifying their restoring force or dissipation mechanisms. In this context, Folded-Pendulum TMDs (FPTMDs) are appealing for tuning low-frequency structures because they are compact and easy to retune while avoiding sliding mechanisms. In turn, Friction Dampers

Time reversal (TR) techniques due to their spatial and temporal focusing characteristics, have been increasing applied in damage evaluation. Since probing waves strongly attenuate in concrete material, imaging of damage in concrete using conventional time reversal imaging (TRI) algorithm often requires a large number of deployed transducers to minimize unexpected artifacts. To relieve economic burden

Harmonic Balance is one of the most popular methods for computing periodic solutions of nonlinear dynamical systems. In this work, we address two of its major shortcomings: First, we investigate to what extent the computational burden of stability analysis can be reduced by consistent use of Chebyshev polynomials. Second, we address the problem of a rigorous error bound, which, to the authors’ knowledge

Theoretical modeling for surface roughness of ball-end milling generally results in low prediction accuracy due to the lack of machining information, excessive computational costs, and uncertainty of manual adjustment parameters. Besides, data-driven methods are limited in practical applications due to the lack of theoretical support or ‘black-box problems’ of neural network. To deal with these problems

Double planetary gear sets (DPGSs) are widely applied to high power and high torque mechanical transmission systems due to the high loading capacity, steady transmission, and high transmission efficiency. Most previous works studied the planetary bearing vibration characteristics without the gear excitations. This work establishes a dynamic model for a DPGS containing all components (sun gear, ring

The real-time analysis of time-varying data has become extremely significant in mechanical systems. The Hilbert–Huang transform (HHT) is a recent development in signal processing based on time–frequency distribution for analyzing complex signals. The HHT permits instantaneous attributes to be used to study signals that display complex behavior and stochastically vary with time. This transform combines

Bonding piezoelectric stack (BPS) is a common type of piezoelectric stack actuator (PSA) with an adhesive bonding layer. The regular bonding layer in BPS is produced by the dielectric materials, which may lead to electric energy dissipation and thus decrease the displacement of BPS. The dissipation can be compensated by substituting the regular bonding with the conductive adhesive (CA) using the conductive

Control of vibrations in fluid transmitting pipes has emerged as a major engineering challenge. For higher fluid flow rate, support vibration, and excitation load, the vibrations in pipes that convey fluid can be complex and, at times, catastrophic. Recent works have demonstrated that Nonlinear Energy Sink (NES) can be effectively employed for passive vibration control of fluid-conveying pipes. The

This study proposes a variable reluctance bearing generator (VRBG) based on a ribbon-shaped soft ferromagnetic cage, that is used in the condition monitoring of bearing cages. A VRBG is composed of an iron coil and a permanent magnet, which are placed on the side of the rolling bearing and fixed to the outer ring of the bearing. Given that the rotating components of the bearing are unchanged, the VRBG

Squeeze film damper (SFD) effectively reduces rotor motion amplitude while crossing critical speeds for vibration and noise reduction in a wide application of aero-engine rotor system. The squirrel cage elastic support (SCES) as an essential component of SFD, accurate modelling of SCES using component modal synthesis (CMS) to account for its flexibility, and calculation of nonlinear oil film forces

As an important connecting component, the hoses transport fluid from pump to pipeline. However, the modeling of connecting hose has been rarely incorporated in the open research of pipeline modeling. To study the natural characteristics of fluid conveying pipeline and the effect of the connecting hose, a new dynamic model of pipeline with connecting hose is established by the finite element method

Compressive spherical beamforming (CSB) with spherical microphone arrays is a panoramic acoustic source identification technology with high spatial resolution and clear acoustic imaging, which has broad application prospects. Due to the discretization of the focus region and the assumption of on-grid sources, classical CSB suffers from the basis mismatch problem, i.e., it faces performance deterioration

In this paper, an amplitude-modulated vibro-acoustic (AMVA) technique using a transmitted amplitude-modulated pump wave to achieve lower power consumption and versatility is proposed to characterize different thermal damage levels of pristine graphene mortar specimens with various dosages. In previous studies, only the primary field u1 and secondary field u2 were considered in the theoretical model

The vibration signal of a faulty rolling bearing exhibits typical non-stationarity – often in the form of cyclostationarity. The spectrum tools often used to characterize cyclostationarity mainly include envelope spectrum, squared envelope spectrum and log-envelope spectrum. In this paper, new detection methods of cyclostationarity are developed for obtaining a larger family of envelope analysis and

A novel method is proposed to correct errors caused by rotational speed fluctuations in the BTT system. The analysis shows that the traditional BTT measurement using the constant speed assumption has low-frequency error due to the integration effect when the rotational speed fluctuation exists. Therefore, a filtering method based on the periodic non-uniform sampling (PNS) theorem is proposed. The details

Parametric accelerated life testing (ALT) with the reliability quantitative (RQ) statements is offered as a reliability methodology to identify and rectify design flaws. The methodology includes: (1) BX lifetime with ALT scheme, (2) fatigue design, (3) ALTs with alterations, and (4) discernment whether the design(s) obtains targeted BX life. A quantum/transport-based life-stress prototype and sample

Structural Health Monitoring (SHM) enables assessing in-service structures’ performance by localizing structural anomaly instances immediately after their occurrence. Typical SHM approaches monitor the entire structural spatial domain aggravating the required density and cost of instrumentation. Further, with model-based approaches, the entire structural domain is needed to be defined with high dimensional

A variable stiffness joint is a key element for structural deformation, which is widely used in morphing mechanisms including mechanical arms, folding wings, etc. By adjusting the stiffness of the joint according to the external environment and/or system instruction, the motion response of the mechanical system can be controlled and its security and stability can be guaranteed. However, to develop

High-frequency noise, which is called gear whine, is a common noise, vibration, and harshness (NVH) problem in the drive axles of commercial vehicles. Although this problem can be solved by gear modification, it is difficult to suppress gear whine effectively because of the difficulty in the selection of the modification parameters. In this paper, on the basis of the combination of the design of experiment

When the vibration excitation intensity is high, the energy dissipation of conventional particle dampers (PDs) is low. The experiment result shows that the three-dimensional grid structure (obstacle grids) in the particle damper can improve the problem of low efficiency of energy dissipation. In order to investigate the influence of obstacle grids on the particles motion and energy dissipation, a numerical

Accurate remaining useful life (RUL) prediction for rolling bearings encounters many challenges such as complex degradation processes, varying working conditions, and insufficient run-to-failure data. Transfer learning (TL), one paradigm of artificial intelligence technology, has demonstrated its powerful performance and great effectiveness for such challenges. As a result, many TL-based solutions

In rotating machinery, non-uniform temperature distribution or hot spots on the rotor surface can induce spiral vibrations. In this paper, a novel experimental apparatus is used to analyze the influence of a hot spot on the dynamic behavior of a flexible rotor supported by oil journal bearings. The hot spot is generated using an induction system with controlled amplitude and phase shift with respect

In order to study the vibration characteristics of inter-shaft bearing failures of a dual-rotor system, an eight-degree-of-freedom dynamic model of dual-rotor system containing inter-shaft bearings is established. The Newmark-β method is used to solve the proposed model equations. The dynamic characteristics of the rotor system when the inner ring and outer ring of the inter-shaft bearing has single-point

Rolling element bearing signals are known to exhibit pseudo-cyclostationary properties that limit the efficiency of health monitoring. This paper investigates the restoration of cyclostationarity of train of impulses generated by bearing faults with the definition of a bearing angle-time relationship. Two main contributions structure the present paper. The first part presents a unifying synthesis of

Judder is a friction-induced torsional vibration generated during clutch engagement in automotive drivelines. To the best of the authors’ knowledge, three are the causes attributed by the scientific community to the onset of the clutch judder: stick-slip phenomena, negative gradient of the coefficient of friction and geometric disturbances. With the help of a methodological approach that integrates

Model updating using multivalued responses is an important approach to construct strongly nonlinear models. During updating, swept frequency tests are usually used to measure the multivalued responses, but the measured responses only contain the stable branches. Accordingly, updating mainly uses these stable responses for the nonlinear model construction. Unstable responses are rarely tested or participate

Unstable chatter seriously reduces the quality of machined workpiece and machining efficiency. In order to improve productivity, on-line chatter detection has attracted much interest in the past decades. Nevertheless, traditional methods are inevitably flawed due to the manually extracted features. Deep learning methods possess outstanding feature learning and classification capabilities, but the generalisation

Spalling is one of the most common contact fatigue failure modes on gear face. Although there are some prediction models for spalling formation, few prediction models have previously addressed the evolution from initial defects to spalling cavities. In this paper, a damage-connectivity spalling model (DCSM) is proposed to describe the formation and evolution of multiple irregular spalling cavities

Bistable nonlinear energy sinks have received great interest due to their efficient broad-band targeted energy transfer over a wide range of input energy levels. The precise identification of bistable nonlinear stiffness force is of significance to predict and enhance the system performance of the vibration energy absorption. However, the nonlinear stiffness force in nonlinear energy sink structures

The study of bearing local defect extension is of importance for bearing health monitoring and management. However, the local defect sizes of rolling bearings are difficult to monitor in real-time. To tackle this problem, a novel digital twin (DT) model is proposed in this paper for dynamical updating and real-time mapping of local defect extension in rolling bearings. The novel DT model is achieved

The extremely rapid reflection of a shock wave from the end wall generated in the shock tube, in addition to the high-frequency content of pressure, inevitably also excites mechanical vibrations. These can potentially produce acceleration-induced spurious signals as part of the dynamic output of the pressure measurement system being calibrated. This paper proposes and evaluates a method for correcting

With the rapid development of pattern recognition represented by deep learning, the massive excellent bearing fault diagnosis methods have emerged. However, the majority of these reports only focus on the diagnosis of single bearing, while there are few works on fault detection of multi-bearing system. Furthermore, many diagnostic models based on vibration signals need to embed an accelerometer in

The present work aims to study the stationary and nonstationary stochastic thermal vibration properties of the laminated combined plate structures using meshless method. The combined system structure consists of several rigidly connected laminated rectangular plates, where the thermal effect of each subplate is considered according to the thermo-elastic theory. The Hamilton’s principle combined with

Railway switches and crossings (S&C, turnouts) connect different track sections and create a railway network by allowing trains to change tracks. This functionality comes at a cost as the load-inducing rail discontinuities in the switch and crossing panels cause much larger degradation rates for S&C compared to regular plain line tracks. The high degradation rates make remote condition monitoring an

The main objective of this paper is to develop a theoretically and numerically reliable and efficient methodology based on combining a finite element method and a strain gradient shear deformation plate model accounting for the nonlinear free and forced vibrations of cellular plates having lattice-type metamaterial cores. The proposed model provides a modelling framework computationally more efficient

Underwater bionic robotics or vehicles using oscillating flexible structures as power sources are attracting considerable attention. In this study, the hydrodynamic effect and fluid–structure coupled vibration of a flexible caudal fin actuated by macro fiber composites(MFC) are investigated. A fluid–structure coupled dynamic equation of the MFC-actuated caudal fin with a variable cross-section is established

Spall is the main form of rolling bearing failure. To assess the bearing health status, this paper proposes a novel method based on the weak magnetic detection technology to estimate the spall size of the rolling bearing. The spall estimation model including the two key parameters of the roller motion speed and the entry-to-exit time is developed. They are both perception by the weak magnetic detection

Disc–block interface properties have prominent influence on the dynamic behaviors of train braking systems. In this study, the tribological characteristics of small-scale train friction blocks with different perforation diameters at the centre of the block surface were investigated using a disc–block test rig. And the Stribeck model parameters of the disc–block friction interface were identified to

Domain generalization (DG) has attracted much attention in bearing fault diagnosis since it can generalize the prior diagnostic knowledge to invisible working conditions. However, previous DG-based approaches are easy to introduce personalized bias due to the specificity of the mechanical equipment, which worsens the generalization performance. To solve this problem, a deep causal factorization network

A hybrid time–frequency method is proposed for accurately estimating the modal parameters of bridges, including the closely spaced modes, by a single-axle scanning vehicle fitted with multi sensors. The novelty of the method is the combined use of the wavelet transform (WT) and singular value decomposition (SVD) for processing the cross covariances of the multi-sensor responses generated by the scanning