http://www.ukm.my/kamal3/psm/pfpstochastics.pdf

The stochastic finite element method: Past, present and future

Since the introduction of the first edition of International Classification of Sleep Disorders: Diagnostic and Coding Manual(ICSD-1)in 1990,national and international meetings were held to openly discuss the ongoing developments of sleep disorders and a new International Classification of Sleep Disorders: Diagnostic and Coding Manual(ICSD-2)was published in 2005.Compared with ICSD-1,the classification of ICSD-2 was developed in a manner compatible with new International Classification of Diseases(ICD-9 and ICD-10)and formed a coordinated system of International Classification of Diseases.The updated version was characterized by the significant improvements of its logicality and clinical practicability,and was more consistent with the International Classification of Disease.The contents of ICSD-2 were introduced in this article.

Brief introduction to second edition of International Classification of Sleep Disorders:Diagnostic and Coding Manual

A review on signal processing techniques utilized in the fault diagnosis of rolling element bearings

A summary of fault modelling and predictive health monitoring of rolling element bearings

Machines without vibrations in the working environment are something non-existent. During machining operations, these vibrations are directly linked to problems in systems having rotating or reciprocating parts, such as bearings, engines, gear boxes, shafts, turbines and motors. Vibration analysis has proved to be a measure for any cause of inaccuracy in manufacturing processes and components or any maintenance decisions related to the machine. The non-contact measurement of vibration signal is very important for reliable structural health monitoring for quality assurance, optimizing profitability of products and services, to enhance manufacturing productivity and to reduce regular periodic inspections. This paper presents a state-of-the-art review of recent vibration monitoring methods and signal processing techniques for structural health monitoring in manufacturing operations. These methods and techniques are used as a tool to acquire, visualize and analyse the sampled data collected in any machining operation which can then be used for decision making about maintenance strategies.

The Vibration Monitoring Methods and Signal Processing Techniques for Structural Health Monitoring: A Review

Analytical and numerical prediction of acoustic radiation from a panel under turbulent boundary layer excitation

This paper introduces a method for determining the transmission coefficient for finite coupled plates using an analytical waveguide model combined with a scattering matrix. In the scattering matrix method, the amplitudes of the structural waves impinging on a junction are separated into incident, reflected, and transmitted components. The energy flow due to each of these waves is obtained using a wave impedance method, which is subsequently used to determine the transmission coefficient. Transmission coefficients for semi-infinite and finite L-shaped plates are investigated for single and multiple point force excitations, and for controlled incident wave sources. It is shown that the transmission coefficients can also be calculated from details of the modal transmission coefficients and the modal composition of the energy incident on the junction. Results show that the modal transmission coefficients are largely independent of whether the plates have finite or semi-infinite boundary conditions, and are only dependent on the details of the coupling. Finally, frequency averaged transmission coefficients are compared for semi-infinite and finite structures. In the cases considered, it is found that the semi-infinite system is a good approximation for finite systems after frequency averaging, especially if the system is excited with multiple point force excitation.

An investigation of transmission coefficients for finite and semi-infinite coupled plate structures

An efficient approach is proposed to predict acoustic scattering with nonuniform potential flow effects for structures with rotational and translational symmetries The convected wave equation is t

Acoustic scattering for rotational and translational symmetric structures in nonuniform potential flow

Active control is applied to an L-shaped plate in order to attenuate the flexural energy transmission from one plate to the other. The coupled plates are simply supported along two parallel sides, and free at the other two ends. Point forces are used to generate the primary and secondary excitation of the plates. The flexural wave coefficients are determined from the boundary conditions, continuity equations at the driving force locations, and continuity equations at the corner junction of the two plates. Bending, shearing, and longitudinal effects are taken into consideration at the corner junction. Under broadband frequency control at a discrete location in plate 2, both the control shaker and the error sensor are optimally located to achieve the best control performance. Results show that when the control force and error sensor are arbitrarily located, the control performance is dependent on the excitation frequency. When both the control force and error sensor are optimally located with respect to the primary shaker location in a symmetrical arrangement, the control performance is both maximized and independent of the excitation frequency. Using single-frequency control to attenuate the total vibrational response of the coupled plates, the error sensor location is strongly mode dependent. It is shown that using a single, properly located control force and a single, properly located error sensor, global attenuation of the L-shaped plate can be achieved.

Active attenuation of the wave transmission through an L-plate junction

In this work, numerical methods to identify the surface areas of a vibrating structure that radiate sound are implemented for cases of structures with inhomogeneous distributions of viscous Rayleig...

/pdf/non-negative-intensity-for-structures-with-inhomogeneous-4dsrjpoy5z.pdf

Nicole Kessissoglou

Papers

Analytical and numerical prediction of acoustic radiation from a panel under turbulent boundary layer excitation

An investigation of transmission coefficients for finite and semi-infinite coupled plate structures

Acoustic scattering for rotational and translational symmetric structures in nonuniform potential flow

Active attenuation of the wave transmission through an L-plate junction

Non-Negative Intensity for Structures with Inhomogeneous Damping