“The vibrations are in the range of just a few kilohertz. They are invisible to the naked eye but very effective. The ice clinging to the wing breaks up and falls off,” explains Denis Becker, a researcher at Fraunhofer LBF.
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Fraunhofer’s innovation bypasses heat altogether. It uses piezoelectric actuators embedded in the wing to send out precise, low-frequency vibrations when sensors detect ice formation. The vibrations cause the frozen layer to crack and detach before it can build up, keeping the surface clean without consuming much power.
Huh. We made them shiver in the cold
Shhh! Don’t tell them about metal fatigue fracture failure!
Have you ever seen a wing during flight? It’s not a stiff structure, they move a lot, and they are designed to withstand a lot vibrations already.
You see motion that is relatively slow and within the fatigue life of the material and within the yield stress. But there’s a reason it called fatigue life. Now let’s take a look at what can happen to metals used in sub sonic applications where the energy levels applied would be less than at sonic levels:
That’s a simple example where the cone is meant to not flex as much as the rubber webbing. Between this application and the use in airplane wings and the use in de-icing the change is frequency. Higher frequency. The wings you can see both the frequency and the amplitude. In the cone you’re only able to see the amplitude unless you illuminated it using a strobe light. Finally as we get into the 20Khz to 100Khz range, both, the amplitude and frequency will be too small to see. But the intent is de-icing so there will be some energy coupled into the material.
Your sonic toothbrush doesn’t last forever. One day you’ll notice that the thing makes the same noise but its weaker. This is either the piezo deaminating or the horn braking off somewhere. But there is definitely a frequency and amplitude range where the fatigue life is infinite or not easily measurable… In 20 years, when none of us are around, these planes start dropping. No problem they’ll call it an investigation, stop flights and give themselves another 20 years. C’mon! Who wants to fly? You? Wait hold on, let me fix the tire hub…we found some issues due to the tragic death of flight whatever. Each issue can be a flight number. Flight numbers are easy to remember. Some design issues could have many flight numbers!
Current aircrafts without this technology also don’t last forever. Airworthiness is checked frequently, using ultrasound and xray for detecting internal microscopic cracks is a standard procedure for some airplanes.
The article mentiones they plan to use it mostly on hidrogen or electric powered aircraft, where there is no usable excess heat from engines. So it’s not something like winglets which are retrofitted on every plane nowadays, they can consider this vibration during design
Oh that sounds more acceptable.