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Arnaud Deraemaeker

   
Keywords piezoelectricity, point load actuaor, piezocomposite
   

Motivation

Piezoelectric transducers are commonly used in active vibration control and structural health monitoring applications. In particular, thin piezoelectric sensors and actuators are used to induce bending vibrations or propagating waves in plate-like structures The main advantages of such transducers are their small size, their high bandwidth and their relatively low price. Typical piezoelectric transducers found on the market are rectangular or circular. Different researchers have however studied the possibility to use more complex shapes. This idea was mainly driven by the active control applications. The first developments in this direction concern triangular actuators. We have developped the correct expressions of the equivalent loads of a triangular piezoelectric transducer in [1]. They are represented in Figure 1. Based on these formulae, we can show that the moment M2 can be canceled if the piezoelectric constants e31 and e32 are of opposite sign (which requires the use of interdigitated electrodes), and the ratio b/l is chosen according to the expression below.

Figure 1 : equivalent loads for a triangular piezoelectric actuator and design of a point load actuator.

Now if the transducer is clamped along its base, the moment M1 and the two point forces P/2 are canceled. We are left with a single point load at the tip of the triangle. The use of such a transducer is illustrated in Figure 2 where the collocated FRF is computed and compared to the FRF for a point actuation. The graph shows the excellent agreement demonstrating that the design of the point-load actuator is efficient. Such transducer can be very usefull for collocated active control applications.

Figur 2 : Clamped plate with a triangular point load actuator : collocated FRF using the triangular actuator and a point load actuation

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Selected publications

[1] A. Deraemaeker, G. Tondreau, and F. Bourgeois. Equivalent loads for two-dimensional distributed anisotropic piezoelectric transducers with arbitrary shapes attached to thin plate structures. Journal of the Acoustical Society of America, 129(2):681–690, 2011.

[2] G. Tondreau, S. Raman, and A. Deraemaeker. Point load actuation on plate structures based on triangular piezoelectric patches. Smart Structures and Systems, 13(4):547–565, 2014.