Topic
Bimorph
About: Bimorph is a research topic. Over the lifetime, 3339 publications have been published within this topic receiving 51880 citations.
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TL;DR: In this article, the sensing effect of cantilever mounted piezoelectric bimorph unimorph and triple layer benders subjected to external mechanical excitations is discussed based on the constitutive equations of these bending devices.
Abstract: Piezoelectric bending mode elements such as bimorph and unimorph benders can be used as both actuation and sensing elements for a wide range of applications. As actuation elements, these devices convert electric input energy into output mechanical energy. As sensing elements, they convert external mechanical stimuli into electrical charge or voltage. In this article, the sensing effect of cantilever mounted piezoelectric bimorph unimorph and triple layer benders subjected to external mechanical excitations are discussed. General analytical expressions relating generated electric voltage (or charge) to the applied mechanical input excitations (moment M, tip force F, and body force p) are derived based on the constitutive equations of these bending devices. It is found that the clamping effect of each component in the bender devices decreases the dielectric constant. The bimorph bender has a higher voltage sensitivity than the unimorph or triple layer bender with the same geometrical dimensions. The dependence of voltage and charge sensitivities on the thickness ratio and the Young’s modulus ratio of the elastic layer and piezoelectric layer under different conditions are discussed and compared for the unimorph and triple layer benders.
102 citations
TL;DR: By taking advantage of the thermal stresses generated by the huge mismatch of material properties in the polymer-silicon bimorph, unprecedented thermal sensitivities can be achieved and provides the basis to develop the ultimate uncooled IR microsensor with unsurpassable sensitivity.
Abstract: Polymeric nanolayers are introduced here as active, thermal-stress mediating structures facilitating extremely sensitive thermal detection based upon the thermomechanical response of a bimaterial polymer-silicon microcantilever. To maximize the bimaterial bending effect, the microcantilever bimorph is composed of stiff polysilicon, with a strongly adhered polymer deposited via plasma-enhanced chemical vapor deposition. The polymer layers with thickness ranging from 20 to 200 nm possess a rapid and pronounced response to temperature fluctuations due to intrinsic sensitive thermal behavior. We show that by taking advantage of the thermal stresses generated by the huge mismatch of material properties in the polymer-silicon bimorph, unprecedented thermal sensitivities can be achieved. In fact, the temperature resolution of our bimaterial microcantilevers approaches 0.2 mK with thermal sensitivity reaching 2 nm/mK; both parameters are more than an order of magnitude better than the current metal-ceramic design. This new hybrid platform overcomes the inherently limited sensitivity of current sensor designs and provides the basis to develop the ultimate uncooled IR microsensor with unsurpassable sensitivity.
102 citations
TL;DR: The designed graphene‐PVDF bimorph actuator exhibits the overall novel performance compared with many other electromechanical avtuators, and may contribute to the practical actuation applications of graphene‐based materials at a macro scale.
Abstract: Smart actuators have many potential applications in various areas, so the development of novel actuation materials, with facile fabricating methods and excellent performances, are still urgent needs. In this work, a novel electromechanical bimorph actuator constituted by a graphene layer and a PVDF layer, is fabricated through a simple yet versatile solution approach. The bimorph actuator can deflect toward the graphene side under electrical stimulus, due to the differences in coefficient of thermal expansion between the two layers and the converse piezoelectric effect and electrostrictive property of the PVDF layer. Under low voltage stimulus, the actuator (length: 20 mm, width: 3 mm) can generate large actuation motion with a maximum deflection of about 14.0 mm within 0.262 s and produce high actuation stress (more than 312.7 MPa/g). The bimorph actuator also can display reversible swing behavior with long cycle life under high frequencies. on this basis, a fish-like robot that can swim at the speed of 5.02 mm/s is designed and demonstrated. The designed graphene-PVDF bimorph actuator exhibits the overall novel performance compared with many other electromechanical avtuators, and may contribute to the practical actuation applications of graphene-based materials at a macro scale.
102 citations
102 citations
TL;DR: The robust magnetic behaviors against mechanical bending were characterized by hysteresis measurements and magnetic force microscopy, which maintain a saturation magnetization of ∼120-150 emu/cm3 under different bending states.
Abstract: A bimorph composed of ferrimagnetic cobalt ferrite (CoFe2O4, CFO) and flexible muscovite was fabricated via van der Waals epitaxy. The combination of X-ray diffraction and transmission electron microscopy was conducted to reveal the heteroepitaxy of the CFO/muscovite system. The robust magnetic behaviors against mechanical bending were characterized by hysteresis measurements and magnetic force microscopy, which maintain a saturation magnetization (Ms) of ∼120–150 emu/cm3 under different bending states. The large magnetostrictive response of the CFO film was then determined by digital holographic microscopy, where the difference of magnetostrction coefficient (Δλ) is −104 ppm. The superior performance of this bimorph is attributed to the nature of weak interaction between film and substrate. Such a flexible CFO/muscovite bimorph provides a new platform to develop next-generation flexible magnetic devices.
101 citations