scholarly journals 3D Printing of Polymeric Multi-Layer Micro-Perforated Panels for Tunable Wideband Sound Absorption

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 360 ◽  
Author(s):  
Yang ◽  
Bai ◽  
Zhu ◽  
Kiran ◽  
An ◽  
...  
Keyword(s):  
3D Printing ◽  
Sound Absorption ◽  
Selective Laser Sintering ◽  
Single Layer ◽  
Noise Pollution ◽  
Optimization Method ◽  
Absorption Coefficients ◽  
Absorption Frequency ◽  
Polyamide 12 ◽  
Subtractive Manufacturing

The increasing concern about noise pollution has accelerated the development of acoustic absorption and damping devices. However, conventional subtractive manufacturing can only fabricate absorption devices with simple geometric shapes that are unable to achieve high absorption coefficients in wide frequency ranges. In this paper, novel multi-layer micro-perforated panels (MPPs) with tunable wideband absorption are designed and fabricated by 3D printing or additive manufacturing. Selective laser sintering (SLS), which is an advanced powder-based 3D printing technique, is newly introduced for MPP manufacturing with polyamide 12 as the feedstock. The acoustic performances of the MPPs are investigated by theoretical, numerical, and experimental methods. The results reveal that the absorption frequency bandwidths of the structures are wider than those of conventional single-layer MPPs, while the absorption coefficients remain comparable or even higher. The frequency ranges can be tuned by varying the air gap distances and the inter-layer distances. Furthermore, an optimization method is introduced for structural designs of MPPs with the most effective sound absorption performances in the target frequency ranges. This study reveals the potential of 3D printing to fabricate acoustic devices with effective tunable sound absorption behaviors and provides an optimization method for future structural design of the wideband sound absorption devices.

Sound Absorption Characteristics of Porous Steel Manufactured by Lost Carbonate Sintering

2009 ◽  
Vol 1188 ◽  
Author(s):  
Miao Lu ◽  
Carl Hopkins ◽  
Yuyuan Zhao ◽  
Gary Seiffert
Keyword(s):  
Absorption Coefficient ◽  
Pore Size ◽  
Sound Absorption ◽  
Single Layer ◽  
Normal Incidence ◽  
Sound Absorption Coefficient ◽  
Absorption Coefficients ◽  
Impedance Tube ◽  
Absorption Characteristics

AbstractThis paper investigates the sound absorption characteristics of porous steel samples manufactured by Lost Carbonate Sintering. Measurements of the normal incidence sound absorption coefficient were made using an impedance tube for single-layer porous steel discs and assemblies comprising four layers of porous steel discs. The sound absorption coefficient was found not to vary significantly with pore size in the range of 250-1500 μm. In general, the absorption coefficient increases with increasing frequency and increasing thickness, and peaks at specific frequencies depending on the porosity. An increase in porosity tends to increase the frequency at which the sound absorption coefficient reaches this peak. An advantage was found in using an assembly of samples with gradient porosities of 75%-70%-65%-60% as it gave higher and more uniform sound absorption coefficients than an assembly with porosities of 75%.

scholarly journals Sound Absorption Coefficient of Different Green Materials Polymer on Noise Reduction

2020 ◽  
Vol 9 (3) ◽  
pp. 2773-2777
Keyword(s):  
Absorption Coefficient ◽  
Noise Reduction ◽  
Sound Absorption ◽  
New Technologies ◽  
Raw Materials ◽  
Agricultural Waste ◽  
Noise Pollution ◽  
Sound Absorption Coefficient ◽  
Absorption Coefficients ◽  
Green Materials

One of the sources of noise pollution to environment is from the consumption of electrical and mechanical appliances usage at home and industries. Growth development and advancement of heavy equipment in construction work further emphasize the necessity used of new technologies for noise reduction. The best technique of control or reducing of noise is by using the materials that can absorb the noise by materials itself. Potential materials from agricultural waste as sound absorber were identified. There are two main objectives in this study; First is to produce acoustic absorber by using natural materials. Second is to identify their sound absorption coefficients. The samples were fabricated using the raw materials from banana stem, grass, palm oil leaves and lemongrass mixed with binding agents of polyurethane and hardener to the ratio of 1:4. The diameters of the samples consist of 28mm and 100mm and the thickness is 10mm. The samples sound absorption coefficients were measured according to standards ASTM E1050-98 / ISO 105342-2 (Impedance tube method). Sound absorption coefficient of the materials depends on frequencies choose. The frequencies values used in this study were in the range from 500Hz to 4500Hz. Material made from grass have a higher average sound absorption coefficient value which is 0.553. All tested samples also can be categories under class D type of materials based on sound absorption coefficient value.

Colorometric study of polyamide-12 powder aging

2020 ◽  
Vol 86 (10) ◽  
pp. 31-35
Author(s):  
N. Ya. Mokshina ◽  
V. V. Khripushin ◽  
M. S. Shcherbakova
Keyword(s):  
3D Printing ◽  
Selective Laser Sintering ◽  
Colorimetric Method ◽  
Critical Factor ◽  
Thermal Exposure ◽  
Practical Experience ◽  
Laser Sintering ◽  
Computer Processing ◽  
Polyamide 12 ◽  
Long Term Storage

The key point of 3D printing by selective laser sintering is the necessity of complete filling of the working chamber of the printer with a powder material. Since the powder is not completely consumed during the printing process, 25 – 30 wt.% of secondary (unused in the previous cycle) power is added to the primary material in each cycle. Repeated recirculation leads to degradation of the properties of the working powder mixture and increases the probability of rejects. We present the results of a colorimetric study of aging of polyamide-12 powder used in 3D printing by the method of selective laser sintering. Scanning and computer processing of digital images of primary and secondary polyamide powders obtained by colorimetry were performed using MathLab program package. Colorimetric analysis included the expression of the sample color using the parameters of color models applied in digital technologies for synthesizing colored images. The number of cycles before the onset of intensive destruction is no more than three, which is consistent with the practical experience in printing by selective laser sintering. The results characterizing change in the color of the secondary powder depending on the duration of thermal exposure and the gas medium are presented. It is shown that long-term storage of the powder for subsequent use is not advisable, since the initiators of destruction are already present in the material. Thermal oxidative destruction is shown to be a critical factor limiting the use of secondary powder along with changes in the crystallinity and fractional composition of particles. Computer processing of images of polymer powder obtained by the colorimetric method can be used to control the aging process of consumables and to predict the probability of rejections in 3D printing.

3D Printing of a Robust Polyamide‐12‐Carbon Black Composite via Selective Laser Sintering: Thermal and Electrical Conductivity

2019 ◽  
Vol 304 (4) ◽  
pp. 1800718 ◽  
Author(s):  
Alejandro H. Espera ◽  
Arnaldo D. Valino ◽  
Jerome O. Palaganas ◽  
Lucio Souza ◽  
Qiyi Chen ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
3D Printing ◽  
Carbon Black ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Polyamide 12

Comparative study on 3D printing of polyamide 12 by selective laser sintering and multi jet fusion

2021 ◽  
Vol 288 ◽  
pp. 116882 ◽  
Author(s):  
Chao Cai ◽  
Wei Shian Tey ◽  
Jiayao Chen ◽  
Wei Zhu ◽  
Xingjian Liu ◽  
...  
Keyword(s):  
3D Printing ◽  
Comparative Study ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Polyamide 12

scholarly journals Use of Nonwovens of Variable Porosity as Noise Control Elements

2001 ◽  
Vol os-10 (4) ◽  
pp. 1558925001os-10
Author(s):  
Yakir Shoshani ◽  
Yakov Yakubov
Keyword(s):  
Sound Absorption ◽  
Noise Control ◽  
Numerical Procedure ◽  
Single Layer ◽  
Linear Quadratic ◽  
Absorption Coefficients ◽  
Variable Porosity ◽  
Noise Absorption ◽  
Functional Forms ◽  
Acrylic Fibers

The optimal design of multilayer combinations of nonwoven fiberwebs is of prime importance in their applications as noise control elements. Such combinations can be simulated as a single layer with variable characteristics along the propagation of the sound wave. The paper examines the effect of variation of porosity on the sound absorption coefficients of three webs made of cotton, acrylic fibers and polyester. The numerical procedure is based upon our generalization of the C. Zwikker and C.W. Kosten theory on sound transfer through porous media reported elsewhere. We have considered four functional forms of the porosity: linear, quadratic, exponential and logarithmic. Our results clearly indicate that for all materials considered the logarithmic form yields the highest noise absorption coefficients for f=1000 Hz.

scholarly journals Bilayer ventilated labyrinthine metasurfaces with high sound absorption and tunable bandwidth

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiayuan Du ◽  
Yuezhou Luo ◽  
Xinyu Zhao ◽  
Xiaodong Sun ◽  
Yanan Song ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Air Flow ◽  
Single Layer ◽  
Sound Waves ◽  
Acoustic Metamaterials ◽  
Sound Barrier ◽  
Free Air ◽  
Relative Bandwidth ◽  
Wide Range ◽  
High Sound

AbstractThe recent advent of acoustic metamaterials offers unprecedented opportunities for sound controlling in various occasions, whereas it remains a challenge to attain broadband high sound absorption and free air flow simultaneously. Here, we demonstrated, both theoretically and experimentally, that this problem can be overcome by using a bilayer ventilated labyrinthine metasurface. By altering the spacing between two constituent single-layer metasurfaces and adopting asymmetric losses in them, near-perfect (98.6%) absorption is achieved at resonant frequency for sound waves incident from the front. The relative bandwidth of absorption peak can be tuned in a wide range (from 12% to 80%) by adjusting the open area ratio of the structure. For sound waves from the back, the bilayer metasurface still serves as a sound barrier with low transmission. Our results present a strategy to realize high sound absorption and free air flow simultaneously, and could find applications in building acoustics and noise remediation.

scholarly journals The Direct 3D Printing of Functional PEEK/Hydroxyapatite Composites via a Fused Filament Fabrication Approach

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 545
Author(s):  
Krzysztof Rodzeń ◽  
Preetam K. Sharma ◽  
Alistair McIlhagger ◽  
Mozaffar Mokhtari ◽  
Foram Dave ◽  
...  
Keyword(s):  
Tensile Strength ◽  
3D Printing ◽  
Selective Laser Sintering ◽  
Fused Filament Fabrication ◽  
Bone Apposition ◽  
Innovative Solutions ◽  
3D Printed ◽  
Work Samples ◽  
Viable Approach ◽  
Crystalline Domains

The manufacture of polyetheretherketone/hydroxyapatite (PEEK/HA) composites is seen as a viable approach to help enhance direct bone apposition in orthopaedic implants. A range of methods have been used to produce composites, including Selective Laser Sintering and injection moulding. Such techniques have drawbacks and lack flexibility to manufacture complex, custom-designed implants. 3D printing gets around many of the restraints and provides new opportunities for innovative solutions that are structurally suited to meet the needs of the patient. This work reports the direct 3D printing of extruded PEEK/HA composite filaments via a Fused Filament Fabrication (FFF) approach. In this work samples are 3D printed by a custom modified commercial printer Ultimaker 2+ (UM2+). SEM-EDX and µCT analyses show that HA particles are evenly distributed throughout the bulk and across the surface of the native 3D printed samples, with XRD highlighting up to 50% crystallinity and crystalline domains clearly observed in SEM and HR-TEM analyses. This highlights the favourable temperature conditions during 3D printing. The yield stress and ultimate tensile strength obtained for all the samples are comparable to human femoral cortical bone. The results show how FFF 3D printing of PEEK/HA composites up to 30 wt% HA can be achieved.

Sign in / Sign up

Export Citation Format

Share Document