Methods of Controlling
Energy Flow

(206 KB .PDF document)



SmartSkin's innovative technology controls noise and vibration in surfaces and surface structures.  It is applicable across any number of industrial platforms.  Products to be differentiated by either weight reduction, volume reduction, cost reduction or improved noise and vibration related performance (or a combination of the above) may be as small as a micro-motor spindle or computer disk drive arm or as large as a military transport aircraft or luxury cruise liner.  Applications include any where noise and vibration are issues and the goal is to control certain frequencies, control a broad band of frequencies or, in some cases, actually enhance and direct certain vibrations for product efficacy.

Noise and vibration-related problems are addressed by passive and active means. Passive solutions rely on additions of damping material to decrease the vibrations. Active solutions rely on control systems with sensors to detect the vibrations and actuators to apply forces to the system that cancel the vibrations. Both approaches are global in that traditionally they need to be applied throughout the system in question to be effective.

The SmartSkin's Technology1 is unique in that it does not have to be applied throughout a system. The Technology actually diverts the vibrations to pre-selected regions where they are subsequently managed. The Technology is proprietary and is protected by strong patents with broadly written claims. The patents teach that the root cause of vibration-related problems is the flow of vibrational energy within a system. By controlling this flow, vibration levels can be reduced to a degree not achievable by conventional passive or active control methods. Further, the narrow frequency ranges addressed by conventional methods are no longer at issue.

The fundamental Technology is termed Vibration Control by Confinement™ (VCC™). VCC™ is implemented by selecting a region where the vibrational energy is to be confined and then moving the energy to that region. When this is done, a higher level of vibrations suppression is realized throughout the remaining portion of the system. The higher vibration levels in the confined region (energy is not dissipated but confined and, therefore, concentrated) actually respond better to control methods. Because the input signals are higher and the areas of confinement are smaller damping methods are more efficient or, depending on the precise area of confinement, unnecessary.

A simple analogy for Energy Flow Control™ can be made by picturing water poured from a point source into a depression to form a shallow pond. If a dam is laid across the middle of the depression before the water is poured in, half of the depression will contain water and the other half will remain empty. The energy, in this case represented by the water, has been confined to one-half of the depression. The dam creates a physical barrier preventing the water from flowing through. Furthermore the energy has been concentrated as the water is twice as deep as it would have been without confinement and half of the depression remains undisturbed.

The fundamental difference between conventional passive and active vibrational energy control schemes and VCC™ is that a traditional scheme assumes vibrational energy affecting a surface and deals with the entire surface while VCC™ addresses vibrational energy affecting a surface, by creating impedance (the dam in the previous example) causing the energy to follow the path of least resistance thereby channeling it to a confined area where it is controlled.

A second patent that is part of the Technology combines VCC™ with a Concentration of Damping Elements (CDE) in the region of confinement. The combination of VCC™ and CDE to control vibrational energy flow throughout a structure is termed Energy Flow Control™ (EFC™).

A good example of Energy Flow Control™ is shown in the following figures.  This Figure shows, in three dimensions, the displacement fields in a vibrating rectangular plate. Such a displacement field is directly proportional to the energy distribution in the plate. The energy distribution at a single frequency (i.e. in a single mode of vibration) is shown. In other words, we are looking at a snapshot of the energy density of the vibrating plate. The intensity color scale at the right side of the figure indicates that red represents the highest positive and blue the lowest negative displacements. The vibration displacement map of an uncontrolled plate in the left figure shows that, at a particular frequency, energy is distributed across the entire plate surface. This also indicates that there are three high-level vibration regions in the plate.

After an Energy Flow Control™ analysis has been performed and a solution has been implemented, the displacement field has been drastically changed as shown by the right-hand figure. In this case, the energy has been moved over to the right side of the plate leaving the left side quiet and undisturbed. This can be accomplished, in many cases, by simply changing the mass and stiffness distribution by adding or removing mass or stiffness from specific regions of the plate. This is a proactive passive solution. Energy redistribution can also be carried out using transducers attached to the plate to affect movement of vibrational energy. This is a proactive active solution. Combinations of proactive passive and proactive active solutions are also possible and may result in the highest performance.

A key point to note here is that the vibration energy is not cancelled. It is simply moved. The total energy in both figures is the same. Since outside energy is not expended to create a "quiet" area in the plate, the Energy Flow Control™ management process is, by nature, extremely efficient.

Taking the Technology to its extreme, "smart" vibration control systems can be devised that perform self-diagnostics. They can sense changes in a structure's vibrational fields and, through a system of actuators, alter the physical characteristics of the host structure to accommodate such change. For example, assume small cracks develop in the skin of an aircraft. A smart system can be built with the capability to diagnose the cracks in flight and cause minute changes in the surrounding structure to relieve the stress causing those cracks. In this instance the system can trigger a cockpit alarm and allow the plane to get to a landing area in advance of catastrophic failure. This is just one of the "futuristic" applications achievable today with the use of the Technology.

1Variations of proprietary Vibration Control by Confinement™ technology and Energy Flow Control™ technology that are patented or have patents pending by SmartSkin's affiliate, Quality Research, Development and Consulting, Inc.
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