Acoustic impedance and absorption coefficient measurements of porous materials used in the automotive industry

Soto, P.F.; Herráez, Marta; González, Ana García; Saja, J.A. de

doi:10.1016/0142-9418(94)90042-6

Cited by 13 publications

(7 citation statements)

References 8 publications

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“…The 5 wt.% PHBV foam was best at low frequency of 500 Hz, while the 25 wt.% PHBV foam was best at a high frequency of 4000 Hz ( Figure 7 a,b). This could be attributed to the large cell size and low foam density displayed by the 5 wt.% PHBV foam and the large air volume contained in the 25 wt.% PHBV foam as shown by its large cell density in Table 3 [ 83 , 84 , 85 ].…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, the large pore size (Ø = 123.48 µm) recorded for the 45 wt.% PHBV foam made it the most effective closed cell foam at low frequency as explained earlier. Conclusively, these results have shown that the acoustic behavior of the porous PCL/PHBV blends especially at low frequencies, which may not totally be a function of their bulk densities [ 84 ]. Apart from the influence of cell density on the absorption properties of the open cell foams, their internal discontinuities and extensive mixed cellular morphology impacted their acoustic impedance property.…”

Section: Resultsmentioning

confidence: 99%

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Carbon Capture Utilization for Biopolymer Foam Manufacture: Thermal, Mechanical and Acoustic Performance of PCL/PHBV CO2 Foams

Oluwabunmi

D’Souza

2021

Polymers

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Biopolymer foams manufactured using CO2 brings a novel intersection for economic, environmental, and ecological impact. PHBV has a low solubility in CO2 while PCL has a high CO2 solubility. In this paper, PCL is used to blend into PBHV and unfoamed and foamed systems are examined. Foaming the binary blends at two depressurization stages with subcritical CO2 as the blowing agent, produced open-cell and closed-cell foams with varying cellular architecture at different PHBV concentrations. Differential Scanning Calorimetry results showed that a reduction in miscibility occurred as the concentration of PHBV increased in PCL matrix, while Scanning Electron Microscopy results showed the occurrence of bimodal cellular properties in some of the foam fractions, which improved their performance properties significantly. The results on the acoustic performance showed limited impact from foaming over the unfoamed blends but mechanical performance of foams showed a significant impact from PHBV presence in PCL. Thermal performance reflected that foams were affected by the blend thermal conductivity, but the impact was significantly higher in the foams than in the unfoamed blends.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Carbon Capture Utilization for Biopolymer Foam Manufacture: Thermal, Mechanical and Acoustic Performance of PCL/PHBV CO2 Foams

Oluwabunmi

D’Souza

2021

Polymers

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“…Many modern cellular types of foam, which are trusted and effective acoustic absorbents, are created from polymeric materials by the use of chemical blowing agents [27]. Using this method it is possible to vary the size and geometry of a foams cellular construction, thus altering the size and cell type and changing its acoustic properties [28]. Historically, evaluating the effectiveness of a given foam or combination of foam layers at absorbing sound energy has been done using experimental measurements [29].…”

Section: Acoustic Treatments In Vehicle Designmentioning

confidence: 99%

Proposal of a Methodology for Multidisciplinary Design of Multifunctional Vehicle Structures including an Acoustic Sensitivity Study

Cameron¹,

Lind²,

Wennhage³

et al. 2009

Int. J. Vehicle Structures and Systems

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In this paper, a design methodology is proposed, wherein tools and knowledge from the areas of structural design, numerical optimization, and noise, vibration and harshness (NVH) engineering are combined into a single toolbox for vehicle design. The methodology attempts to address the topic of sustainable development from both economic and environmental perspectives within the vehicle industry. A brief review of the topics of NVH and numerical optimization is given for the purposes of disseminating knowledge. Finite element codes for predicting structural and acoustic response are implemented within the iterative design methodology, which is explained for generic problems. Specific focus is placed on the need for understanding functional requirements of the entire system rather than its components. The methodology is implemented in an automotive case study. The results in terms of design solution and development framework are evaluated and discussed. As part of this evaluation, and integral to the design process, an acoustic sensitivity analysis of the final solution is performed and the results are presented.

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“…However, to the best of our knowledge, all PC foams investigated in the literature either are closed cells foams or those with open‐cell, their sound and thermal insulation behavior were not scientifically examined. Closed cell foams would show a reasonable thermal insulating behavior, but their sound insulation properties would, as usual, be very low . For sound waves to be attenuated by the foam, cells must be interconnected so that air particles can pass through them …”

Section: Introductionmentioning

confidence: 99%

Characterization of the Structure, Acoustic Property, Thermal Conductivity, and Mechanical Property of Highly Expanded Open‐Cell Polycarbonate Foams

Jahani

Ameli

Saniei

et al. 2014

Macro Materials & Eng

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This paper studies the processing, structural, and property relationships needed for highly expanded open-cell polycarbonate (PC) foams. Acoustic insulation, thermal conductivity, and mechanical properties of the foams were characterized. Using foam injection molding, samples expansion ratios ranging from 1 to 8 and open-cell content up to 85% were prepared. Relative to their solid counterparts, the sound wave transmission loss was increased up to 2.5-fold while their thermal conductivity was decreased up to fivefold. Thus, lightweight rigid PC foams, useful in both sound and thermal insulation applications, were developed.

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Acoustic impedance and absorption coefficient measurements of porous materials used in the automotive industry

Cited by 13 publications

References 8 publications

Carbon Capture Utilization for Biopolymer Foam Manufacture: Thermal, Mechanical and Acoustic Performance of PCL/PHBV CO2 Foams

Carbon Capture Utilization for Biopolymer Foam Manufacture: Thermal, Mechanical and Acoustic Performance of PCL/PHBV CO2 Foams

Proposal of a Methodology for Multidisciplinary Design of Multifunctional Vehicle Structures including an Acoustic Sensitivity Study

Characterization of the Structure, Acoustic Property, Thermal Conductivity, and Mechanical Property of Highly Expanded Open‐Cell Polycarbonate Foams

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