Acoustic panel

Jet engine cones, hydraulic fluid tanks for j et engines, stiffeners of acoustic panels, spacers for engine acoustic panels, protection hoods, empennages, supports for satellite antennas. 

Acoustical control can also be achieved by proper space planning. For instance, workstations that are positioned too closely do not provide suitable speech privacy and can be a source of disturbing conversational noise. As a generi rule, a minimum of 8-10 ft between employees, separated by acoustical panels or partitions, wUl provide normal speech privacy. 

Yaodonghua Furniture Boards Co. Ltd 100,000 Board, furniture, acoustic panel, chipboard, MDF panel, slot, board, plywood, particle board http //yaodonghua. gmc.globalmarket.com... 

Needle-punching Blankets Carpet underlay/backing Upholstery (including synthetic leathers) Wadding and padding/fibre-fill Wall coverings and acoustic panels... 

ARPRO P-EPP JSP International, F 22-82 Up to 100 Acoustical panels used for noise ... 

One specific example concerns the sound-deadening, so-called acoustic panels . These are fitted to the front (position B in Fig. 76) and the rear of the engine and comprise a structurally bonded sandwich panel where a perforated aluminium, titanium or stainless steel top skin is bonded to the honeycomb core. 

The perforated skins are usually pretreated by grit abrasion and then, occasionally, primed with a surface protection primer such as Redux 122 or with an adhesion-promotion primer. The adhesive is epoxy based and can be in film or in paste form. The acoustic panel so formed is either bonded directly to the engine casing or is first closed with a glass-reinforced epoxy laminate to promote stiffness and this GRP skin is then bonded directly to the casing. 

CFM 56 Here both aluminium and carbon reinforced composite sandwich panel constructions are used. An aluminium bondment forms the inner structure of the acoustic panel. Perforated, Redux 119 primed skins are bonded to aluminium honeycomb, Redux 319 film adhesive having first been reticulated onto the core. The outer structure is a conventional bondment of a carbon reinforced composite skin bonded to the core. 

Of all the current civil engines. Rolls Royce s Trent 7(X) does have high temperature requirements. The IFS of the thrust reversers has to operate for considerable periods of time at elevated temperatures (> 140-150°C). The component manufacturers, Hurel-Hispano, believe that this is asking too much of an epoxy adhesive and hence a Cytec-Fiberite BMI film adhesive (FM-2550) is used to bond this structure. Here the BMI adhesive is reticulated onto phosphoric acid anodised aluminium honeycomb. The core is then bonded directly onto pre-cured carbon-reinforced BMI laminates to form a sandwich structure, one of the skins being perforated to produce an acoustic panel , which helps reduce engine noise. 

CeUular urea—formaldehyde and phenoHc resin foams have been used to some extent in interior sound-absorbing panels and, in Europe, expanded polystyrene has been used in the design of sound-absorbing doors (233). In general, cost, dammabUity, and cleaning difficulties have prevented significant penetration of the acoustical tile market. The low percent of redection of sound waves from plastic foam surfaces has led to their use in anechoic chambers (216). 

Metal Pan Assemblies. These units consist of tiles and panels formed from perforated aluminum or steel with pads of fiber glass or mineral wool inserted into the pans to provide the sound absorption. They are used primarily for ceilings in a similar manner to acoustical tiles and panels. The pads are sometimes sealed in plastic film to prevent absorption of moisture, dirt, and odors. The perforated metal is relatively sound transparent and functions as the finished ceiling and the support for the sound-absorbing material. The perforated metal by itself has no acoustical value. 

Pressure-sensitive adhesives (PSAs) based on acrylic, natural rubber and silicone are employed primarily for ease of application. To name Just a few applications, PSAs bond decals to surfaces, interior decorative surfaces to interior panels, interior trim pieces in place directly or hook and loop tape for the same purpose, structural shims in place during manufacturing and acoustic (sound deadening) materials to body skin interior surfaces. Tape products with pressure-sensitive adhesive on one or both surfaces are used for such functions as cargo compartment sealing, as a fluid barrier to prevent spills and leaks in the lavatories and... 

Because of their cellular or open-matrix construction, most insulants have an inherent ability to absorb sound, act as panel dampers and reduce noise breakout from plant by their ability to be a flexible or discontinuous link between an acoustically active surface and the outer cladding. This secondary aspect of thermal insulation specification will gain more prominence when the UK adopts the EC Directive 86/1888, Protection of workers from the risks related to exposure to noise at work . 

Medium-density mat with flexible facings of paper or scrim stitched through. Quilts are used for acoustic absorption behind perforated or slatted panels and ceilings. 

Acoustic louvers constructed of the absorbent panel material (suitable for a small degree of noise reduction only) ... 

Fig. 5.17 Comparison of the experimental PVDOS determined from NIS measurements on Fe (TPP)(NO) (upper panel) with the PVDOS predicted on the basis of DFT calculations using the B3LYP (center panel) and BP86 (lower panel) functionals. Blue traces represent the PPVDOS Dp (v)for oriented crystals (see Appendix 2, Part III, 3 of CD-ROM), scaled by a factor of 3 for comparison with the total PVDOS Dpe(v)of unoriented polycrystalline powder (red traces). Since the X-ray beam direction k lies 6° from the porphyrin plane, modes involving Fe motion in the plane of the porphyrin are enhanced, and modes with Fe motion primarily normal to the plane are suppressed, in the scaled oriented crystal PVDOS relative to the powder PVDOS. In-plane Fe modes dominate the 200-500 cm range of the data, while Fe motion in modes observed at 74, 128, and 539 cm is predominantly out-of-plane. Crosshatching in the upper panel indicates the area attributable to acoustic modes. In the lower two panels, the Fe-NO bend/stretch modes predicted at 386 and 623 cm , have been artificially shifted to the observed 539 cm frequency to facilitate comparison with the experimental results. Predicted PVDOS are convolved with a 10 cm Gaussian (taken from [101])...

A one hour fire wall or "substantial space" should be provided between the turbine and gas compressor. The utilization of explosion blow-out panels in the acoustical enclosure will also limit damage from an explosion. Although strengthen panels could be provided to protect against shrapnel ejection, the cost installation coupled with the low probability of such an occurrence and the low personnel exposure periods, generally render this a non-cost effective safety improvement. 

A high molecular weight PP resin composition, has been prepared which has excellent acoustic properties and rigidity and high specific gravity suitable for use in acoustic instruments including speaker panels or boxes. 

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