Showing papers in "Journal of Sound and Vibration in 2015"

TL;DR: In this article, motion magnification has been developed for visualizing exaggerated versions of small displacements with an extension of the methodology to obtain the optical flow to measure displacements, which can be extended to modal identification in structures and the measurement of structural vibrations.

TL;DR: In this paper, a piecewise nonlinear dynamic model is formulated in the consideration of possible disengagement between the cam and roller, and the analytical solution of the amplitude-frequency relationship is derived by using the averaging method and further verified by numerical simulations.

TL;DR: In this article, the inerter-based isolators have two unique properties, which are more attractive than the traditional DVA: first, the inertance-to-mass ratio of the Inerter based isolators can easily be larger than the mass ratio without increasing the physical mass of the whole system; second, there is no need to mount an additional mass on the object to be isolated.

TL;DR: In this article, a finite element model (FEM) is developed to predict the modal and frequency response of different configurations of the metamaterial plates and a Floquet-Bloch approach is exercised to demonstrate the stop band and mechanical filtering capabilities over a broad range of frequencies.

TL;DR: In this paper, the attenuation characteristics of the T(0,1) and L (0,2) guided wave modes over a range of sand conditions, including loose, compacted, mechanically compacted and water saturated, were investigated using a laboratory full-scale experimental rig and model predictions.

TL;DR: In this paper, the results of an experimental study on turbulent flow over a flat plate with a serrated sawtooth trailing edge were presented, where a pair of pressure-driven oblique vortical structures near the saw-tooth side edges were identified.

TL;DR: In this article, a single-degree-of-freedom geometrically nonlinear oscillator with stable-quasi-zero-stiffness (SQZS) is presented, which can be extensively applied in vibration isolation.

TL;DR: In this paper, a torsion vibration isolator with quasi-zero stiffness (QZS) is proposed to attenuate the transmission of torsional vibration along a shaft system, which also plays a role of coupling between shafts.

TL;DR: In this paper, a review of literature concerned with the vibration modelling of rolling element bearings that have localised and extended defects is presented, along with analytical models to approximate these vibration signals.

TL;DR: The current paper will illustrate the use of robust regression for SHM data analysis through experimental data acquired from the Z24 and Tamar Bridges, although the methods are general and not restricted to SHM or civil infrastructure.

TL;DR: In this paper, a tuned mass damper with a continuous variable transmission and gear-ratio control system is proposed, which enables stepless and accurate changes of inertance, and the damping properties of the proposed device with respect to one-degree-of-freedom harmonically forced oscillator are examined.

TL;DR: In this article, various types of dynamic wind effects commonly encountered for suspension and cable-stayed bridges are discussed, emphasizing the importance of the structural dynamics of the bridge structures and emphasizing the role of the wind effects on the bridge structure.

TL;DR: In this paper, a technique for the extraction of backbone curves of lightly damped nonlinear systems that is well suited for the experimental investigation of structures exhibiting nonlinear behaviour is presented. But the method is based on estimations of the instantaneous frequency and the envelope amplitude of a decaying response following a tuned steady-state oscillation of the system.

TL;DR: In this article, a low-order model is developed comprising a linear acoustic network and an improved analytical form for a flame describing function (FDF), which includes both the saturation of the amplitude of heat release rate perturbations and the change of phase lag relative to oncoming acoustic velocity fluctuations when the instability grows into a limit cycle.

TL;DR: In this article, an effective medium method is developed to calculate sound transmission loss (STL) of a metamaterial thin plate consisting of periodic subwavelength arrays of shunted piezoelectric patches bonded to the two surfaces of an unbounded homogeneous thin plate.

TL;DR: In this article, a simple, stiff, statically and dynamically stable linear oscillator incorporating a negative stiffness element is used as a template to provide a generic theoretical basis for a novel vibration damping and isolation concept.

TL;DR: In this paper, a Kundt-like measurement method of the reflection coefficient of a beam termination is proposed, which is validated using theoretical results in the case of beam free end.

TL;DR: Wang et al. as mentioned in this paper presented a study on acoustic emission detection of rail defect at high speed based on rail-wheel test rig Meanwhile, Wavelet Transform and Shannon entropy are employed to detect defects Signals with and without defects are acquired, and characteristic frequencies from them at different speeds are analyzed based on appropriate decomposition level and Energy-to-Shannon entropy ratio, the optimal wavelet is selected in order to suppress noise effects and ensure appropriate time resolution, the length of time window is investigated Further, the characteristic frequency of timewindow is employed to detecting defect.

TL;DR: In this article, the authors explore the connection between the nonlinear normal modes of an undamped and unforced nonlinear system and the isolated resonance curves that may appear in the damped response of the forced system.

TL;DR: In this article, a nonlinear and fractional derivative viscoelastic (FDV) model is used to capture the complex behavior of rail pads and is implemented into the dynamic analysis of coupled vehicle-slab track (CVST) systems.

TL;DR: In this article, the forced response of a primary linear oscillator with vibro-impact energy sink was studied and a chaotic strongly modulated response (CSMR) was identified due to the special structure of a slow invariant manifold.

TL;DR: In this article, the authors proposed a procedure for the parameterized TFA to analyze the non-stationary vibration signal of varying-speed rotary machinery, which is used for fault detection, system condition monitoring, parameter identification, etc.

TL;DR: Wang et al. as mentioned in this paper explored the active role of healthy pattern in fault classification and proposed a new fusion feature extraction method based on locality preserving projections (LPP) to discover the local feature pattern difference between each bearing status and the healthy condition to characterize and discriminate different bearing statuses.

TL;DR: In this article, a method for accurately calculating ball passing frequency (BPF) based on a complete dynamic model of rolling ball bearings with localized surface defects is proposed, where three-dimensional motions, relative slippage, cage effects and localized surface defect are all considered.

TL;DR: In this article, an approach was used to extract the full-field dynamic strain on a wind turbine assembly subject to arbitrary loading conditions, such as pluck testing, impact hammers, and mechanical shakers.

TL;DR: In this paper, an analytical formulation of the load distribution and varying effective stiffness of a ball bearing assembly with a raceway defect of varying size, subjected to static loading in the radial, axial and rotational degrees of freedom is presented.

TL;DR: In this article, a parametric proof-of-concept study was performed to investigate the effectiveness of porous treatment on bare tandem cylinders to control and regularize the vortex shedding and flow within the gap region between the two bluff bodies, and thereby control the aerodynamic sound generation mechanism.

TL;DR: In this article, an active seat system is proposed to reduce the vibration level transmitted to the seat pan and occupants' body under low frequency periodic excitation, where a Filtered-x least-mean-square (FXLMS) adaptive control algorithm with online Fast-block LMS identification process is employed to manage the system operation for high vibration cancellation performance.

TL;DR: In this article, a six degree of freedom (six-dof) vibration isolator is presented, as well as the control algorithms necessary for stabilizing the passively unstable maglev system.

TL;DR: In this paper, a three-dimensional nonlinear dynamic model is proposed to predict the skidding behavior of angular contact ball bearings under combined load condition, and the model is verified through comparison with the tested results of the reference.