Research on Obtaining Biocomposite Structures with Sound Absorbing Properties

Abstract

The paper addresses the methodology for obtaining biocomposite structures from waste, with sound-absorbing properties, such as: thuja shells, walnut shells, pistachio shells, beech sawdust, pumpkin seeds shells and sunflower seeds shells. The experimental analysis carried out considers the study of the sound-absorbing properties held by the proposed new biocomposite materials, by determining the value of the sound absorption coefficient, reflection coefficient, impedance ratio, using the Kundt tube. The interpretation of the results obtained from the evaluation of biocomposites shows that they have sound-absorbing properties. Consequently, sound-absorbing panels with soundproofing properties can be made from these materials, which can be used in industry, transportation, construction, etc. as well as for decorative purposes in spaces such as cinemas, malls, spas, etc.

Design of Melamine Foam/perforated Plates Composite Absorber for Effective Sound Absorption Performance

“…As a classical five-parameter semi-empirical equivalent fluid model, the Johnson-Champoux-Allard (JCA) model is adopted in this study [27][28][29]. The effective density ρ(ω) and effective volume modulus K(ω) expressed by the model are as follows: (1)…”

“…In order to solve noise pollution problem, great efforts have been put into the research of various sound absorption materials and methods. In this regard, porous sound absorbing materials, resonant sound absorbing structures and composite structure have been widely used due to their outstanding advantages in sound absorption [1][2][3].…”

Tunable Acoustic Properties Using Different Coating Systems on Resonance Spruce Wood

“…The amount of reflection was provided by the sound reflection coefficient (usually denoted SRC), which depends on the material surface profile, the frequency of the traveling wave, and the incident angle which is the angle between the wavefront and the normal direction to the surface. [45][46][47][48][49] The impedance tube provided the conditions of normal incidence investigations (null angle), with the controlled frequency band of the incident waves.…”

“…Each sample (1) was inserted into the sample holder of the impedance tube (2), type 4206, Brüel&Kjaer (Naerum, Denmark), and acoustic signals with the frequency range 100 Hz-6.4 kHz were generated inside the tube using the loudspeaker (3); the signals provided by microphones (4) were acquired by a conditioner-DAQ board system (5), and finally were transmitted to a computer system ( 6)-see the schematic diagram in the Figure S2a,c (Supporting Information). [45][46][47][48] The samples were investigated on both: the unvarnished (denoted "a") and the varnished (denoted "b") sides, in order to identify the differences between sound absorption/reflection coefficients caused by the varnish layers (Figure S2a,c, Supporting Information).…”

Preparation and Modification of Flexible Polyurethane Foam for Effective Flame Resistance and Sound Absorption

“…Noise pollution problem, as a major pollution problem in the world, affects our daily lives all the time and causes a series of detriments to human health [1,2]. Reducing the noise from the source is a good way to solve the noise pollution problem, but it is difficult to realize in many conditions.…”