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Piezoelectric Capture of Energy in Tires

Piezoelectric materials can convert mechanical energy to electrical energy, and vice versa. Some interesting ideas have been proposed to use this property to harness energy from heat or vibration. One such idea is to recover energy from the wheels of a running vehicle. In a typical setup for this application, piezoelectric units are bonded to the inner liners of tires. As the wheels rotate, the tires continually deform and relax as they interact with the road, causing the piezoelectric units to generate a periodic voltage with a speed-dependent frequency. The energy that is generated can be used as auxiliary power to prolong the life of batteries (see Ref.).

In this Brief, we demonstrate this idea using ADINA. The simulation of a rolling wheel was conducted, as shown in the above movie. The movie below shows a small time range of the complete simulation, around the time when the bonded piezoelectric unit rotates to the lowest position and passes over the road.

Figure 1 shows the segment of the tire where the inner surface is bonded with the piezoelectric unit, which is composed of a brass reinforced layer and a PZT (lead zirconium titanate) layer. The brass and PZT layers are both 0.2 mm thick.

Figure 1  Piezoelectric unit embedded in tire

In practice, the brass layer is taken as the bottom electrode while another electrode is put on top of the PZT layer, and both electrodes are separately wired. The bottom electrode is modeled in ADINA by fixing the interface of the two layers at a zero voltage, and the top electrode is modeled using constraint equations to ensure a uniform voltage on the surface during the simulation. The next movie shows the variation of the effective stress around the piezoelectric unit as the tire interacts with the road.

Figure 2 shows the dynamic voltage response of the PZT layer. The three jumps on the voltage response curve correspond to the three times of the piezoelectric unit on the tire interacting with the road.

Figure 2  Voltage response of the embedded PZT layer

This use of ADINA for piezoelectric modeling and simulation demonstrates the great potential for similar applications using ADINA in multiphysics analyses.

For more examples of the powerful multiphysics capabilities of ADINA, see ADINA Multiphysics.

Reference

• N. Makki and R. Pop-Iliev, "Piezoelectric Power Generation In Automotive Tires", Proc. Smart Materials, Structures & NDT in Aerospace Conference, Montreal, Canada 2011.

Keywords:
Piezoelectric, tire, rolling wheel, transducer, voltage response, sensor, PZT, multiphysics