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Full-Text Articles in Mechanical Engineering
Acoustic And Dynamic Characteristics Of A Complex Urban Turnout Using Fibre-Reinforced Foamed Urethane (Ffu) Bearers, Sakdirat Kaewunruen
Acoustic And Dynamic Characteristics Of A Complex Urban Turnout Using Fibre-Reinforced Foamed Urethane (Ffu) Bearers, Sakdirat Kaewunruen
Sakdirat Kaewunruen
A special track system used to divert a train to other directions or other tracks is generally called ‘railway turnout’. A traditional turnout system includes rails, switches, crossings (special track components), steel plates, fasteners, screw spikes, timber bearers, ballast and formation. The wheel rail contact over the crossing transfer zone has a dip-like shape and can often cause detrimental impact loads on the railway track and its components. The large impact also emits disturbing noises (either impact or ground-borne noise) to railway neighbors. In a brown-field railway track where an existing aged infrastructure requires renewal or maintenance, some physical constraints …
Sound Absorption Properties Of Functionally Graded Polyurethane Foams, Olivier Doutres Ph.D., Noureddine Atalla Pr.
Sound Absorption Properties Of Functionally Graded Polyurethane Foams, Olivier Doutres Ph.D., Noureddine Atalla Pr.
Olivier Doutres Ph.D.
Noise control over a wide frequency band is an increasingly important design criterion in the building and transport industries. Examples of well known broadband passive concepts for optimal sound absorption are multi-layering with graded properties across the thickness and optimization of the material shape (e.g., wedges). However, for typical applications, the material thickness is limited and shaping or use of different material costly. Thus, there is growing interest for developing acoustical materials having microstructure properties gradient at the micro- or meso-scale; also known as Functionally Graded Materials (FGM). Even if sophisticated models are available to predict the acoustic behavior of …