Sound Barrier Applications of Recycled Plastics

1998 ◽  
Vol 1626 (1) ◽  
pp. 85-92 ◽  
Author(s):  
M. Ala Saadeghvaziri ◽  
Keith Macbain
Keyword(s):  
Finite Element ◽  
Analytical Model ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Finite Element Analyses ◽  
Sound Barrier ◽  
Recycled Plastics ◽  
Material Tests

An innovative noise wall design that uses recycled plastic and takes advantage of multilayering to increase stiffness and sound effectiveness is proposed and analyzed. Prototypes of the proposed design were constructed and tested for sound transmission to determine their effectiveness and show the desirability of a multilayered approach. The results show that, acoustically, the transmission loss of the proposed design is as effective as traditional designs. Furthermore, finite element analyses as well as an analytical model developed specifically for recycled plastics indicate that, structurally, the proposed design can increase spans between posts resulting in a design that is potentially more economical than current designs. Results of material tests conducted in support of the analytical model and noise wall development are also discussed.

Analytical and Experimental Investigation on Sound Transmission of Double Thin Plates with Magnetic Negative Stiffness

2018 ◽  
Vol 10 (05) ◽  
pp. 1850054 ◽  
Author(s):  
Akintoye Olumide Oyelade ◽  
Yi Chen ◽  
Ruojun Zhang ◽  
Gengkai Hu
Keyword(s):  
Finite Element ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Interaction Force ◽  
Negative Stiffness ◽  
Thin Plates ◽  
Acoustic Metamaterials ◽  
Element Analysis ◽  
Theoretical Formulation ◽  
Wave Condition

Transmission loss of acoustic metamaterials (AM) made of double thin plates with magnetic (negative) stiffness was analyzed using theory, finite element analysis and experimental techniques. The theoretical formulation was done using a rectangular duct below the first cut off frequency, the model is then validated against finite element method and experiment. Two cubic magnets were used, their interaction force and the resulted magnetic stiffness were calculated. The sound transmission loss (STL) of the structure is calculated for plane wave condition, the addition of magnetic mass shifts STL peaks to the lower frequency compared to a structure without mass. The slight increase in STL for small negative stiffness in experiment is not enough to cancel the effect of air compressibility. However, a significant enhancement could be expected if negative stiffness can be made large enough in the double thin plates. The developed AM can be employed as a prospective sound engineering control at low frequency.

New Analytical Model of Bolted Joints

2004 ◽  
Vol 126 (4) ◽  
pp. 721-728 ◽  
Author(s):  
Ouqi Zhang ◽  
Jason A. Poirier
Keyword(s):  
Finite Element ◽  
Analytical Model ◽  
External Load ◽  
Bolted Joints ◽  
Finite Element Analyses ◽  
Conventional Theory ◽  
New Model ◽  
Proposed Model ◽  
Compression Members ◽  
Additional Member

The conventional theory of bolted joints adopts equivalent cylinders, cones or spheres for compression members. In this model, the member deformation is determined by the member stiffness that remains unchanged whether the external load is present. In fact, the external load causes an additional member deformation that is not determined by the member stiffness measured at pre-load. The external load also causes a member rotation, which not only reduces the member stiffness, but also delays the separation of the joint. Based on these observations, a new model of bolted joints is developed. Finite element analyses is performed to verify the proposed model.

scholarly journals Assessment of the primary rotational stability of uncemented hip stems using an analytical model: Comparison with finite element analyses

2008 ◽  
Vol 3 (1) ◽  
pp. 44 ◽  
Author(s):  
Maria E Zeman ◽  
Nicolas Sauwen ◽  
Luc Labey ◽  
Michiel Mulier ◽  
Georges Van der Perre ◽  
...  
Keyword(s):  
Finite Element ◽  
Analytical Model ◽  
Model Comparison ◽  
Rotational Stability ◽  
Finite Element Analyses ◽  
Hip Stems

Biobased insulating panels from mulberry stems

2021 ◽  
pp. 089270572110108
Author(s):  
Vijaykumar Guna ◽  
Manikandan Ilangovan ◽  
Narendra Reddy ◽  
PG Radhakrishna ◽  
VH Maharaddi ◽  
...  
Keyword(s):  
Transmission Loss ◽  
Sound Transmission ◽  
Green Building ◽  
Barrier Properties ◽  
Sound Transmission Loss ◽  
Sound Waves ◽  
Soil Burial ◽  
Sound Barrier ◽  
Automotive Parts ◽  
Pp Composites

In this work, Mulberry Stems (MS) obtained as a by-product of sericulture have been used as reinforcement for Polypropylene (PP) composites intended for green building, furniture and automotive applications. Mulberry stems are lignocellulosic and are renewable and sustainable sources but remain unutilized and are usually discarded as waste by burning or burying. An attempt has been made to utilize mulberry stems as substitutes for commonly used non-biodegradable composites using a simple and clean fabrication technique. The effects of reinforcement percentage (80% to 95% w/w) of MS and density (0.5 g cm−3 to 1.25 g cm−3) of composites on the properties have been studied. Results revealed that, 90/10 (MS/PP w/w %) was the optimum ratio that provides highest mechanical strength. Increasing the density enhanced the strength, thermal insulation, sound transmission loss, water stability and flame retardancy. The 1.25 g cm−3, 90/10 ratio composite had a high sound transmission loss of 46.6 dB and thermal conductivity of 0.130 W/mK which is 70% lower than neat gypsum board used in false ceiling applications. The high insulation and sound barrier properties of mulberry stem based composites are due to the unique hollow morphology of MS which aids in efficient absorbtion and dissipation of the thermal energy and sound waves. Weight loss of MS/PP composite after soil burial test for 120 days varied between 8.9% and 31.4%. MS/PP composites could be potentially used as a green replacement for ply, particleboards, false ceiling, automotive parts and other applications.

scholarly journals Study of the Hershel-Quinke Resonator

2020 ◽  
Vol 320 ◽  
pp. 00025
Author(s):  
Veronika Nikolaeva ◽  
Alexandr Komkin
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Analytical Model ◽  
Transmission Loss ◽  
Geometric Parameters ◽  
Numerical Calculations ◽  
Element Modeling

In this paper, the transmission loss of a Herschel-Quincke resonator is investigated. An analytical model of such a resonator is considered. The finite element modeling of the resonator has also been carried out. It is shown that the resonance peaks of the transmission loss spectrum in the analytical model are shifted relative to the results of numerical calculations, as a result of which it is necessary to introduce corrections for the length of the resonator tubes into the analytical model. The amendments made it possible to correct the results of analytical calculations, ensuring their reliability. The dependence of the resonator bandwidth as a function of its geometric parameters is investigated.

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