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Electrically Responsive Materials and Devices Directly Driven by the High Voltage of Triboelectric Nanogenerators
摘要： Smart materials with electrically responsive characteristics and devices relying on different electrostatic effects can be directly driven by triboelectric nanogenerators (TENGs). The open circuit voltage from a TENG can easily reach thousands of volts with a separation distance of a few millimeters and this high output voltage can be used to effectively drive or control some devices with high internal resistance. This kind of combination is the most straightforward way for achieving a self-powered smart system. Hence, a detailed survey of electrically responsive materials and devices that can be successfully combined with TENG is summarized, including dielectric elastomers, piezoelectric materials, ferroelectric materials, electrostatic manipulators, electrostatic air cleaners, and field emission and mass spectrometers. Moreover, key factors in determining suitable materials or devices to work with TENG are clarified and an in-depth discussion of the current challenges related to these combined systems is provided. With the cost-effectiveness and simple manufacturing process, these TENG-based composite systems have great application prospects in the field of smart mechanics, human–machine interaction systems, intelligent storage systems, self-powered microfluidic chips, portable mass spectrometers, and so on.
关键词： piezoelectric materials,mass spectrometers,electrostatic air cleaners,dielectric elastomers,electrically responsive materials,self-powered systems,field emission,electrostatic manipulators,triboelectric nanogenerators,ferroelectric materials
更新于2025-09-10 09:29:36
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Smart Materials and Structures: State of the Art and Applications
摘要： The world of materials is an exciting and challenging field of research since it has always played a dominant role in the evolution of human civilization. The demands from aerospace, defence, automotive and industrial branches on more advanced and innovative materials has led to the development of a new generation of materials with much better performance and capabilities than the existing conventional structural and functional materials. As a result, the era of smart materials has started. Smart materials can change their physical properties in response to a specific stimulus input. However, there is still a blurry image over the types and potential applications of smart materials. The objective of this paper is to define the field of smart materials and structures, together with its current status and potential benefits. However, more focus will be devoted to piezoelectric materials and results are presented and discussed. Finally, and in order to demonstrate the characteristics of one class of smart materials, two numerical examples are proposed and results are presented.
关键词： Piezoelectric materials,Actuators and sensors,Smart materials,Shape memory alloys
更新于2025-09-10 09:29:36
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Finite Element Modellingand Simulations of Piezoelectric Actuators Responses with Uncertainty Quantification
摘要： 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.
关键词： finite element method,uncertainty quantification,piezoelectric materials,unimorph actuator,energy harvesting,PZT
更新于2025-09-10 09:29:36
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Applications of Piezoelectrics: Old and New
摘要： Piezoelectric materials convert electrical energy to mechanical energy and vice versa, resulting in observed properties that are electromechanically coupled. When a piezoelectric is deformed, that mechanical energy is transformed to electrical energy, which is known as the direct piezoelectric effect. When the reverse occurs, and an electric field is applied, the material physically deforms, resulting in the converse piezoelectric effect. Therefore, piezoelectric materials can be used in both sensor and actuator applications. The magnitude of the piezoelectric response is often expressed as the longitudinal piezoelectric coefficient, d33. When measuring the direct piezoelectric effect, d33 is the polarization generated per unit of mechanical stress, where the field and stress are along the same direction. In the converse effect, d33 is the induced mechanical strain per unit of electric field applied, with the field and stress also in the same direction. Another measure of effectiveness of a piezoelectric is called the electromechanical coupling factor, k. This value expresses the efficiency of conversion from mechanical to electrical energy or vice versa.
关键词： actuator applications,electromechanical coupling factor,sensor applications,direct piezoelectric effect,Piezoelectric materials,converse piezoelectric effect
更新于2025-09-09 09:28:46