CFRP Fig.4: Test sample Fig. 5: Carbon fibre reinforced plastic (CFRP) coated with a damping elastomer thermal energy. The material loss factor, η, is defined as follows: Tab. 5: Summary of average damping performance Bare EAR alumi0.05" nium EAR 1/8" EAR 3/8" Pyrotec SP150 3/8" (2) Loss factor η = ΔW 2π W Where: W is the energy of one vibration cycle; ΔW is the energy absorbed by one vibration cycle. The following relations (work [2]) between the bending rigidity of a tough epoxy layer B and a soft spring polyester layer B1 can be varied from one to four. B/B1 = (fc/f1)2 x (1+ ρ/ρ1x t/t1)2 (3) Where: B is the bending rigidity of the epoxy layer; B1 is the bending of the rigid polyurethane layer; fc is the resonance frequency; f1 is the frequency of free vibration; ρ is the density of the epoxy layer; ρ1 is the density of the polyurethane layer; t is the thickness of the epoxy layer; t1 is the thickness of the polyurethane layer. The resonance frequency can be predicted from equation (3) as follows: NeoNeoAdvent Advent (5" (1/2" insulation) insulation) Avg. 2001000 Hz 0.003 0.028 0.100 0.293 0.224 0.066 0.044 Avg. above 1000 Hz 0.004 0.034 0.111 N/a N/a 0.085 0.078 surfactant is a unique organic surfactant that can be used as a replacement for silicon-based surfactants. The Dabco DMDEE blowing agent is an amine blowing catalyst used in rigid foam sealant systems and for flexible systems. The JEFSOL EC-50 ethylene carbonate solvent is made of cyclic organic esters produced by reaction of ethylene/propylene oxide with carbon dioxide. Experimental samples One of the main problems was to create amultifunctional material with fire protection properties. A Teflon fluorocarbon liquid was used for fire protection. Figure 2 shows a design sample for damping and acoustic protection. A polyester layer was used on the aluminium fuselage wrapped up with CFRP. A wood foam was designed for multifunctional spray technology. An aluminium foil was used to separate the wood from the CFRP and polyester layers. Fire protecting recycled crumb rubber inside a polyurethane filling is shown in Figure 3. Polyester with rubber has fire protection properties. Figure 4 represents a model test sample consisting of a damping CFRP (Loctite® epoxy resin) layer and a polyester acoustic layer. An upper tough polyurethane fire block provides fire protection. fc = (B/B1)1/2 f1 (1+ ρ/ρ1 x t//t1)1/2 (4) Testing a new damping treatment A material's vibration damping performance is its ability to absorb the imposed vibration energy and to convert it into Fig. 6: Composite damping loss factor of various damping treatments Tab. 6: Sound absorption coefficients at frequencies ranging from 125 to 4000 Hz [9] 1000 Hz 2000 Hz 4000 Hz 0.2 0.4 0.55 0.55 0.45 0.65 0.65 0.65 0.75 0.75 0.7 Insulation thickness, inch 125 Hz 250 Hz 300 Hz 0.5 0.04 0.1 1 0.06 0.2 2 0.15 0.4 0.75 1 0.07 0.25 0.7 0.9 0.75 0.7 2 0.25 0.7 0.9 0.85 0.75 0.75 0.5 0.05 0.15 0.35 0.5 0.6 0.6 58 jec composites magazine / No97 May - June 2015