Piezoceramics

Piezoceramics are pretty special, the term piezo means that the material generates electricity based upon mechanical stress.

 

Strength Durability Hardness Weight
N/A (4 / 5) (4 / 5) (4 / 5)
Elasticity Flexibility Plasticity Availability
(1 / 5) (2 / 5) (1 / 5) (5 / 5)

Advantages

Creates electrical energy when deformed, Vibrates when electrical energy is applied, hard, resistant to wear, good resistance to heat

Disadvantages

Brittle, Low flexibility, Eventually loses functionality

Piezoceramics create small amounts of energy when they are placed under pressure or have vibrations run through them they are also capable of creating vibrations when electricity is run through them.This gives them three unique properties detecting vibration, creating vibrations and harvesting energy from vibrations. There are three videos that show these factors working below.

Detecting Vibration – Knock Sensor

  • Detecting vibrations ranges from strong vibrations as seen in the example above to very subtle vibrations down to 20mhz
  • Accurately gives feedback on what vibration is occurring, used as for tuning musical instruments.
  • Sensitivity is lost over time so subtle tones will be lost first, however the piezo still has a very good useful lifetime.
  • High sensitivity makes the piezo more sensitive to high temperatures which will cause the piezo to stop functioning in much the same way a magnet stops functioning.

Creating Vibrations

  • Vibrations create noise and can be controlled by how much power is input.
  • The will be a natural resonant frequency for any piezo where it will move the most.
  • Vibration can be used to control actuators on fine machinery and is used in precise positioning of tools like lasers.

Harvesting Electricity

  • Harvesting electricity requires a capacity or battery, piezo only produces a consistent voltage under a controlled vibration.
  • Energy produced is low but can be amplified with more piezo or clever design.

Factors

Where will you find them?
Easiest place to find them is in starter electronic kits or online electronics shops. They come mostly as discs bonded to a metal disc to provide support. They are cheap and readily available. Can be found as actuators or sheets, there is a large amount of options if you wish to use the piezoceramic in traditional applications.

Whats the lifetime like?
Depends on the sensitivity, the less sensitive the longer the life.

Use in design
Inappropriate for use in large sections and should not be treated like a regular ceramic. Nearly always found bonded to another material to provide support and stop the ceramic from cracking and breaking into shards.

 

Written By

James Burchill

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