Performance Of Piezoelectric Sensors Research Articles

Modeling of Actively Damped Beams with Piezoelectric Actuators with Finite Stiffness Bond

The piezoelectric strain actuation of beams has been extensively studied. It is well known that a number of non-idealities may affect the performance of piezoelectric sensors or actuators. In particular, the existence of a finite stiffness bond between the actuator and the structure causes a reduction in the effectiveness (or sensitivity) of induced strain actuators (or sensors) mounted on the surface of a structure. This effect may be significant for short actuators and/or less stiff bonding layers. The objective of this work is to assess the influence of a finite stiffness bond between piezoelectric sensors/actuators and the structure on the active damping of beams subjected to rigid body rotations and elastic deformations. The depoling of the piezoelectric material is also taken into account in the model. A finite element formulation that incorporates this effect is proposed. The formulation uses an Euler-Bernoulli model for the beam and assumes the bond layer to be in a state of pure shear. The effect of the finite bond stiffness appears explicitly in the electro-mechanical coupling matrix. The present formulation includes the effect of the finite bond stiffness with good approximation without introducing extra degrees of freedom in the system. Active damping is introduced in the beam by a simple control law using rate feedback. A numerical example indicates that, within certain limits, the finite stiffness bond may be compensated for by using a higher gain in the control system. However, the finite bonding stiffness has to be taken into account when designing the control system.

Piezoelectric and Capacitative Microactuators and Devices

AbstractUltrasonic transducers, microactuators and resonators using sol gel PZT films, polymer membranes and silicon machining techniques can take the form of cantilevers, membranes, and array sensors. Static deflections in simple electrode configurations for PZT films supported on silicon or silicon nitride membranes are of the order of 1 μm, while larger deflections can be developed under ac and resonant excitation. High frequency acoustic actuators using capacitative excitation of polymer films have been used to evaluate the performance of piezoelectric sensors.

Force measurement with a piezoelectric cantilever in a scanning force microscope

Detection of surface forces between a tip and sample has been demonstrated with a piezoelectric cantilever in a scanning force microscope (SFM). The use of piezoelectric force sensing is particularly advantageous in semiconductor applications where stray light from conventional optical force-sensing methods can significantly modify the local carrier density. Additionally, the piezoelectric sensors are simple, provide good sensitivity to force, and can be batch fabricated. Our piezoelectric force sensors will be described, the theoretical sensitivity and performance of piezoelectric sensors will be discussed and experimental measurements of sensitivity and imaging results will be presented.

Performance characterization of piezoelectric sensors in smart composite structures

The increased use of fiber‐reinforced composites in primary structural components has created a need for effectively monitoring the structural integrity of these composite components. Piezoelectric sensors may provide one means of ensuring composite integrity. This paper examines the results of a research effort to characterize the performance of piezoelectric sensors in smart composite structures subjected to low‐velocity impact. A series of low‐velocity impact tests was made on composite specimens equipped with attached and embedded piezoelectric sensors. The tests were designed to help establish the relationship of sensor response to impact location and energy for a variety of sensor and composite material configurations. Impact wave characteristics within the composite were studied by theoretical modeling (indentation method, 3‐D F.E M., theory of plates), in order to better understand composite behavior at the sensor site. These results combined with sensor material properties (coupling coefficients, etc.) were used to predict sensor response to impact. Last, a comparison was made of experimental and theoretical sensor responses in order to develop impact detection methodology.