Constrained Acoustic Metamaterial (CAM)

Overview

Constrained Acoustic Metamaterial (CAM) is the best applied where air flow to the device is not a requirement for operation.  Our engineering team has experience in creating custom solutions in commercial aviation manufacturing where noise control is the focus of our work.  In this situation the environment on each side of the surface is separate for many reasons.  Sound levels vary within the cabin with an emphasis placed on flight crew and First Class cabin areas.   Traditionally, those in the forward cabins endure a less intense noise level than those aft of the engines and flight control surfaces.  Our ongoing work provides for an acoustic panel custom engineered for each location within the aircraft.   The results are dramatic, no longer are the quiet seats only forward of the jet engines.

After receiving a profile of the noise your team is working to abate, using our custom designed computer technology we will develop a three-dimensional structure unique to your solution.  Looking at the image to the right, we will determine the best value of each variable in the design equation.  Only is this way can optimum performance be achieved – we do not attempt to provide a one-size-fits-all solution.  Your application is important and merits the time and energy of a custom solution.  The design of the frame and constraint stick along with the proper membrane material are elements of the custom design which vary based on the noise profile.

Applications

Our design team will test and recommend the correct product for your application.  CAM offers a constrained membrane as an integral part of the custom designed solution.  The materials used in the membrane and the frame will be specific and unique to your application.  Our team will consider changes in temperature, pressure in addition to vibration etc.  Through testing we can be certain of the effectiveness of the solution.  Generally CAM is used where the exchange of air or air flow is not required for operation of the equipment.  Aircraft fuselage is a highly probable application where we have years of experience.  Medical equipment in the healthcare sector is another application.  Sound barriers in the outdoors or on the exterior of buildings is a good example also.

Case Studies

CAM system vs. Aluminum Plate

The images below are from the work our team completed and demonstrate the effectiveness of the CAM System.  Notice Figure 1 which shows no noise reduction material – the dB level is 91.8.  Contrast this to a solid aluminum plate, which from Figure 5 we can see weighs 191.90 grams, the result on the sound level from the placement of the solid aluminum plate is 74.7 dB – Figure 2.  Figure 3 and 4 clearly show the effectiveness of the CAM solution – the noise level is reduced to 65.7 dB and the weight of the plate is only 41.51 grams.

We can achieve similar results for you – contact us today.

Figure 1: 91.8 dB, No CAM Applied

Figure 2: 74.7 dB, Aluminum Plate Applied

Figure 3: 65.7 dB, CAM Applied

Diagram 1: Sound Transmission Loss

Figure 4: CAM, .7 kg/m2

Figure 5: Aluminum Plate, 3.3 kg/m2

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