Bimorph

About: Bimorph is a research topic. Over the lifetime, 3339 publications have been published within this topic receiving 51880 citations.

Comparison of collocation strategies of sensor and actuator for vibration control

Abstract: Some possible collocation strategies of sensor and actuator pairs for the application to active vibration control systems are analyzed, compared and discussed in this paper. This is becausea well-designed sensor — actuator collocation configuration can provide a simpler control algorithm with excellent performance and stability, especially when velocity feedback is adopted. As an ideal point collocation pair of a sensor and actuator shows high possibility in actual vibration control problems, the advantage of a collocated accelerometer — shaker pair is proven experimentally and discussed first. Then as a similar approach, a collocated piezosensor — piezoactuator pair is analyzed in depth with the in-plane motion coupling. Finally, two configurations of a practically collocated configuration with an accelerometer — piezoactuator pair and a non-overlapped collocated pair of a bimorph piezosensor — two bimorph piezoactuators are described in detail in terms of performance and stability with experimental results. Those two configurations are expected for the applications to more practical active control of vibration systems with the velocity feedback control scheme.

Resonant Polymeric Waveguide Cantilever Integrated for Optical Scanning

Abstract: We present SU-8 as an optical waveguide and its integration into a functional one- and two-dimensional (1-D and 2-D) scanning device. The waveguide is fabricated as a tapered structure and cantilever beam (100times85times2100 mum). It is mounted onto a 2-D coupled bimorph piezoelectric actuator and driven at resonant frequencies of 4.71 kHz in the vertical and 25 Hz in the horizontal. This raster motion allows for 2-D image scanning when in combination with a light source and detector. An analysis of the polymer's optical capabilities has shown mode coupling efficiencies of 96% and measured a total power output intensity of 20% with a 633-nm light source. The output power can be attributed to the butt-end coupling misalignment, scattering losses due to surface roughness, and absorption. The total vertical tip displacement is 669 mum with an angle of 25 deg when driven with a 47-mum base excitation. A specific application for the design is in the area of endoscopy, where there is a need for a minimally invasive device that reduces the discomfort experienced by the patient. SU-8 as the functional waveguide is the initial phase in creating a microfabricated endoscope system

Material nonlinear characteristics of the 3203HD PZT wafer under high electric fields

Abstract: In this paper, material nonlinear behavior of a PZT wafer (3203HD, CTS) under high electric fields and stress is experimentally investigated and the nonlinearity of the PZT wafer is numerically simulated. Empirical functions that can represent the nonlinear behavior of the PZT wafer have been extracted based on the measured piezoelectric strain under stress. The functions are implemented in an incremental finite element formulation for material nonlinear analysis. New definitions of the piezoelectric constant and the incremental strain are incorporated into the finite element formulation for a better reproduction of the nonlinear behavior. With the new definition of the incremental piezo-strain, the measured nonlinear behavior of the PZT wafer has been accurately reproduced even for high electric fields. For validation of the measured nonlinear characteristics and the proposed approach, a PZT bimorph beam actuator has been numerically and experimentally tested. The predicted actuation displacement based on the material nonlinear finite element analysis showed a good agreement with the measured one.

Finite Element Modellingand Simulations of Piezoelectric Actuators Responses with Uncertainty Quantification

Abstract: Piezoelectric structures are widely used in engineering designs including sensors, actuators, and energy-harvesting devices. In this paper, we present the development of a three-dimensional finite element model for simulations of piezoelectric actuators and quantification of their responses under uncertain parameter inputs. The implementation of the finite element model is based on standard nodal approach extended for piezoelectric materials using three-dimensional tetrahedral and hexahedral elements. To account for electrical-mechanical coupling in piezoelectric materials, an additional degree of freedom for electrical potential is added to each node in those elements together with their usual mechanical displacement unknowns. The development was validated with analytical and experimental data for a range of problems from a single-layer piezoelectric beam to multiple layer beams in unimorph and bimorph arrangement. A more detailed analysis is conducted for a unimorph composite plate actuator with different design parameters. Uncertainty quantification was also performed to evaluate the sensitivity of the responses of the piezoelectric composite plate with an uncertain input of material properties. This sheds light on understanding the variations in reported responses of the device; at the same time, providing extra confidence to the numerical model.