JEC COMPOSITES MAGAZINE - Issue #97 - Special JEC Americas - May/June 2015 - 59

The testing system consisted of an electrodynamic shaker and a vibration response detector. Modal testing (Figure 4) was performed on
a new damping treatment developed by Neo-Advent Technologies
LLC. The treatment is a combination of two separate treatments: a
thin epoxy resin damping layer and a thick polyester foam insulation
layer. The treatment was tested by Noise Control Engineering LLC.
The total thickness of insulation was approximately 5". The treatment
was also tested with the insulation trimmed down to approximately
½ inches to determine the influence of the insulation on damping
performance. The thickness of the thin damping layer was approximately ½ inches. Photos of both thicknesses of the Neo-Advent
treatment are provided in Figure 7. The nominal dimensions of the
aluminium beams were 48 x 2 x 0.193 inches.
A summary of the damping performance of the Neo-Advent
treatment is provided in Table 5. The values in this table represent
the linear average composite damping loss factors of the aluminium
beam and the treatments over two frequency ranges, 200-1000 Hz
and above 1000 Hz. A plot of the composite damping loss factors
as a function of frequency is provided in Figure 6. The loss factor
of aluminium was designated ηal, equalling 0.003 at an average
frequency of 200-1000 Hz and 0.004 above 1000 Hz. The loss factor of Neo-Advent 5" and 1/2" insulation was designated, respectively, ηin5", equalling 0.066 at an average frequency of 200-1000 Hz,
and ηin 1/2" equalling 0.044.
Relations are: ηin 5"/ηal equals 22 at an average frequency of 2001000Hz and ηin 1/2"/ηal equals 14.7 above 1000 Hz. It can be seen
that the loss factor for EAR 1/8", EAR 3/8" and Pyrotek SP150
3/8" is 3.5 times higher than for Neo-Advent insulation at an average frequency of 200-1000 Hz (see Figure 6).
The damping performance of the Neo-Advent treatment is between
that of EAR 0.05" and 1/8", and is significantly lower than that of
EAR 3/8" and Pyrotek SP150 3/8". This means that vibration is approximately 3.5 times lower. The damping effect of the Neo-Advent
insulation appears at frequencies below 500 Hz. The damping loss
factors of Neo-Advent insulation are significantly low at a 500 Hz
frequency. Figure 6 shows the damping performance of the NeoAdvent treatment and Figure 7 shows photos of the Neo-Advent
treatment. The results were compared with those of work [2]. When
coating the carbon fibre reinforced plastic (CFRP) with a damping
elastomer, the loss factor η changed from 0.01 to 0.100 (see Figure
5). Table 6 presents the sound absorption coefficients at frequencies
ranging from 125 to 4000 Hz [9]. Table 6 shows that the lowest
coefficients of sound absorption are found at frequencies ranging

from 125 to 300 Hz, and the highest ones in the 1000-4000 Hz range.
Soft polyester is a good acoustic insulation material, absorbing a lot of
sound. In work [10], the author measured the absorption coefficient
and acoustic impedance.

Conclusion
A CFRP carbon fibre fuselage with polyester damping protection
showed that the epoxy adhesive layer works together with the polyester layer, with an insulation thickness that can reach 5 inches. The
damping effect of the Neo-Advent insulation appears at frequencies
below 500 Hz. Compared to traditional insulation materials EAR
1/8"-3/8" and Pyrotek SP150 3/8", the damping loss factors of the
Neo-Advent insulation are significantly low at frequencies below
500 Hz. The lowest coefficients of sound absorption are found at
frequencies ranging from 125 to 300 Hz, and the highest ones in the
1000-4000 Hz range. n
More information:
www.neo-adventtec.com
References
[1] Boeing Simulates Thermal Expansion in Composites with
Expanded Metal Foil for Lightning Protection of Aircraft Structures,
Tech Briefs , vol. 38, No.7, 2014
[2] Shigemitsu Kurano, Experimental Study on Effects of Elastomer
Coating on the vibration damping property of steel and CFRP Plates
for Ship's Hull, 2002
[3] Advanced Materials Enabling High Volume Road Transport
Applications of Lightweight Structural Composite Parts,
vol. 50, No.3, 2014
[4] EAR noise control, vibration damping, sound insulation, www.
Earsc.com/HOME/Products/index.asp? SID=5.2012
[5] Pyrotek Sound Insulation - Brierley House & Handling, www.
brierleyhouse.com.au/pyrotekSound.php, 2012
[6] Florock Polymer Flooring System/ Industrial Epoxy Coating,
www. Florock.net, 2010
[7] Loctite® Epoxy Marine, m.loctiteproducts.com/p/13/0/7/epxy...s,
Loctite-Epoxy-Marine
[8] Loctite Spray Adhesive High Performance from Loctite Adhesives
www.loctiteproducts.com/...high/.../Loctite-Spray-Adhesive-HighPerformance.htm
[9] Acoustic Thermal Insulation Panel for Walls-Biwall-Buildtec,
www.buildtec.ie/biwall-acoustic-insulation, 2013
[10] Daniel A. Russel, Absorption Coefficient and Impedance, Science
and Mathematics Department, Kettering University, Flint, MI, 48304

No97 May - June 2015 /

jec composites magazine 59

http://www.neo-adventtec.com http://www.Earsc.com/HOME/Products/index.asp http://www.Earsc.com/HOME/Products/index.asp http://brierleyhouse.com.au/pyrotekSound.php http://brierleyhouse.com.au/pyrotekSound.php http://www.Florock.net http://m.loctiteproducts.com/p/13/0/7/epxy...s http://www.loctiteproducts.com/...high/.../Loctite-Spray-Adhesive-High http://www.buildtec.ie/biwall-acoustic-insulation http://www.jeccomposites.com/news/jec-composites-magazine-digital-release

JEC COMPOSITES MAGAZINE - Issue #97 - Special JEC Americas - May/June 2015

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #97 - Special JEC Americas - May/June 2015