Download or read book Experimental Investigation and Theoretical Modeling of Piezoelectric Actuators Used in Fuel Injectors written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Piezoelectric stack actuators are increasingly used in micropositioning applications due to their precision and responsiveness. Advanced automotive fuel injectors have recently been developed that utilize multilayer piezoelectric actuators. Since these injectors must operate under high dynamical excitations at high temperatures, understanding their thermo-electro-mechanical performance under such operating conditions is crucial to their proper design. In this thesis, the effect on soft Lead Zirconate Titanate (PZT) piezoelectric actuators of different controlling parameters relevant to fuel injection is studied experimentally. These parameters include electric-field magnitude and frequency, driving-field rise time, DC offset, duty-cycle percentage, and ambient temperature. Soft PZT actuators generate a significant amount of heat when driven under high electric-field magnitudes and/or high frequency, both of which occur in fuel injectors. They also exhibit hysteretic nonlinear behavior when driven under high electric-field magnitudes. Self-heating and hysteretic nonlinearity are interconnected, and both are undesirable in applications that require precise positioning, such as fuel injection. Self-heating in PZT stacks is considered to be caused by ferroelectric hysteretic nonlinearity, originating from domain-switching. Theoretical studies of self-heating and domain-switching in PZT materials are developed in this thesis. An analytical self-heating model based on the first law of thermodynamics is presented that accounts for different parameters such as geometry, magnitude and frequency of applied electric field, duty-cycle percentage, and surrounding properties. It also directly relates self-heating in PZT actuators to displacement-electric field loss (displacement hysteresis), which is found to increase linearly with increased temperature. The model shows reasonable agreement with experimental results at low and high electric-field magnitudes. A novel domain-switch.
Download or read book Experimental Investigation and Numerical Modelling of Hydrogen Exposed Piezoelectric Actuators for Fuel Injector Applications written by Yadvinder Singh and published by . This book was released on 2013 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Piezoelectric actuators are increasingly used for the electronic control of fuel injector opening valves. Hydrogen is considered an attractive clean alternative fuel for automobile and power generation applications. Current understanding of the performance of piezoelectric actuators in a hydrogen environment is very limited. This work is aimed at experimentally investigating the performance of hydrogen-exposed piezoelectric actuators under conditions directly relevant to a hydrogen-based fuel injector. The performance is assessed with both quasi-static and dynamic electric loads. It is found that up to 12 weeks of continuous exposure to hydrogen at 100°C and 10 MPa has a negligible effect on the actuator stroke when testing is conducted at temperatures of 5-80°C. Cyclic exposure and exposure done on fatigue cycled actuators also yields similar results. Microstructure and dielectric investigations confirm this behavior. The reason for a negligible effect of hydrogen is attributed to the presence of a protective ceramic insulation around the lateral surface of actuators which deactivates the hydrogen diffusion mechanism. A fully-coupled 3-D FEM-based numerical model of a Thermo-Electro-Mechanical continuum in hydrogen environment is developed using the 'Equation Based Modeling' feature of COMSOL Multiphysics. The model provides a useful tool for understanding the localized responses of the actuators in hydrogen environment and to predict their durability and applicability under different conditions.
Download or read book IUTAM Symposium on Multiscale Modelling of Fatigue Damage and Fracture in Smart Materials written by Meinhard Kuna and published by Springer Science & Business Media. This book was released on 2010-11-12 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Today, multi-functional materials such as piezoelectric/ferroelectric ceramics, magneto-strictive and shape memory alloys are gaining increasing applications as sensors, actuators or smart composite materials systems for emerging high tech areas. The stable performance and reliability of these smart components under complex service loads is of paramount practical importance. However, most multi-functional materials suffer from various mechanical and/or electro-magnetical degra-dation mechanisms as fatigue, damage and fracture. Therefore, this exciting topic has become a challenge to intensive international research, provoking the interdisciplinary approach between solid mechanics, materials science and physics. This book summarizes the outcome of the above mentioned IUTAM-symposium, assembling contributions by leading scientists in this area. Particularly, the following topics have been addressed: (1) Development of computational methods for coupled electromechanical field analysis, especially extended, adaptive and multi-level finite elements. (2) Constitutive modeling of non-linear smart material behavior with coupled electric, magnetic, thermal and mechanical fields, primarily based on micro-mechanical models. (3) Investigations of fracture and fatigue in piezoelectric and ferroelectric ceramics by means of process zone modeling, phase field simulation and configurational mechanics. (4) Reliability and durability of sensors and actuators under in service loading by alternating mechanical, electrical and thermal fields. (5) Experimental methods to measure fracture strength and to investigate fatigue crack growth in ferroelectric materials under electromechanical loading. (6) New ferroelectric materials, compounds and composites with enhanced strain capabilities.
Download or read book Coupled Electro mechanical System Modeling and Experimental Investigation of Piezoelectric Actuator driven Adaptive Structures written by Su-Wei Zhou and published by . This book was released on 1994 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analytical and Experimental Investigation of Flutter Suppression by Piezoelectric Actuation written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-11 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research was to analytically and experimentally study the capabilities of piezoelectric plate actuators for suppressing flutter. Piezoelectric materials are characterized by their ability to produce voltage when subjected to a mechanical strain. The converse piezoelectric effect can be utilized to actuate a structure by applying a voltage. For this investigation, a two-degree-of-freedom wind tunnel model was designed, analyzed, and tested. The model consisted of a rigid wing and a flexible mount system that permitted a translational and a rotational degree of freedom. The model was designed such that flutter was encountered within the testing envelope of the wind tunnel. Actuators made of piezoelectric material were affixed to leaf springs of the mount system. Command signals, applied to the piezoelectric actuators, exerted control over the damping and stiffness properties. A mathematical aeroservoelastic model was constructed by using finite element methods, laminated plate theory, and aeroelastic analysis tools. Plant characteristics were determined from this model and verified by open loop experimental tests. A flutter suppression control law was designed and implemented on a digital control computer. Closed loop flutter testing was conducted. The experimental results represent the first time that adaptive materials have been used to actively suppress flutter. They demonstrate that small, carefully placed actuating plates can be used effectively to control aeroelastic response. Heeg, Jennifer Langley Research Center RTOP 505-63-50-15...
Download or read book Piezoelectric Actuators written by Hu Huang and published by BoD – Books on Demand. This book was released on 2021-12-08 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Taking advantage of high resolution, rapid response, and compact structure, piezoelectric actuators are widely employed for achieving precision positioning in both scientific research and industrial application. With the development of science and technology, the requirements for precision positioning are increasing. Accordingly, great efforts have been made to improve the performances of piezoelectric actuators, and significant progress has been achieved. This book discusses some recent achievements and developments of piezoelectric actuators, in terms of piezoelectric material, driving principle, structural design, modeling, and control, as well as applications.
Download or read book A Theoretical and Experimental Study of Piezoelectric Unimorph Actuators for Active Flow Control written by Jose Mathew and published by . This book was released on 2002 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Piezoelectric Actuators and Generators for Energy Harvesting written by Sergey N. Shevtsov and published by Springer. This book was released on 2018-04-20 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents new approaches to R&D of piezoelectric actuators and generators of different types based on established, original constructions and contemporary research into framework of theoretical, experimental, and numerical methods of physics, mechanics, and materials science. Improved technical solutions incorporated into the devices demonstrate high output values of voltage and power, allowing application of the goods in various areas of energy harvesting. The book is divided into seven chapters, each presenting main results of the chapter, along with a brief exposition of novel findings from around the world proving context for the author’s results. It presents particular results of the Soviet and Russian schools of Mechanics and Material Sciences not previously available outside of Russia.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1992 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Piezoelectric Multilayer Beam Bending Actuators written by Rüdiger G. Ballas and published by Springer Science & Business Media. This book was released on 2007-03-06 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the application of piezoelectric materials, particularly piezoceramics, in the wide field of actuators and sensors. It gives a step-by-step introduction to the structure and mechanics of piezoelectric beam bending actuators in multilayer technology, which are of increasing importance for industrial applications. The book presents the suitability of the developed theoretical aspects in a memorable way.
Download or read book Piezoelectric Actuators Vector Control Method written by Frederic Giraud and published by Butterworth-Heinemann. This book was released on 2019-04-18 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: Piezoelectric Actuators: Vector Control Method: Base, Modeling and Mechatronic Design of Ultrasonic Devices guides researchers and engineers through the process of implementing the vector control method (VCM) in their systems. The book presents which measurements can be made, how to visualize a variable as a rotating vector, about the angular position of the rotating reference frame, how to calculate the parameters of the controllers, and how to observe key variables. Additionally, the book focuses on the modeling of PE ultrasonic transducers and investigates the energy conversion process in an ultrasonic transducer. • Presents the fundamentals of the VCM at a basic level for researchers and practitioners who are new to the field. • Simulates several MATLAB and Simulink examples for deeper learning of the subject. • Presents the application to several test cases, with actual measurements obtained on experimental test benches. • Describes practical implementations of the method.
Download or read book Validation of High Displacement Piezoelectric Actuator Finite Element Models written by Barmac K. Taleghani and published by . This book was released on 2000 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The paper presents the results obtained by using NASTRAN® and ANSYS® finite element codes to predict doming of the THUNDER piezoelectric actuators during the manufacturing process and subsequent straining due to an applied input voltage. To effectively use such devices in engineering applications, modeling and characterization are essential. Length, width, dome height, and thickness are important parameters for users of such devices. Therefore, finite element models were used to assess the effects of these parameters. NASTRAN® and ANSYS® used different methods for modeling piezoelectric effects. In NASTRAN®, a thermal analogy was used to represent voltage at nodes as equivalent temperatures, while ANSYS® processes the voltage directly using piezoelectric finite elements. The results of finite element models were validated by using the experimental results.
Download or read book Experimental Characterization and Modeling of Electro Mechanically Coupled Ferroelectric Actuators written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Piezoelectric actuators used in nano-positioning devices exhibit highly non-linear behavior and strong hysteresis. The rate-dependence of piezoelectric materials resulting from the kinetics of domain switching is an important factor that needs to be included in realistic modeling attempts. This thesis provides a systematic study of the rate-dependent hysteresis behavior of a commercially available PZT stack actuator. Experiments covering full as well as minor loops are conducted at different electro-mechanically coupled loading conditions with polarization and strain recorded. In addition, the creep behavior at different constant levels of the electric field is observed. These experiments provide evidence of kinetics being characterized by strongly varying relaxation times that can be associated with different switching mechanisms. Finally, an electro-mechanically coupled free energy model for polycrystalline ferroelectrics is presented that is based on the theory of thermal activation. It is capable of predicting the hysteretic behavior along with the frequency-dependence present in these materials. The electro-mechanically coupled model also predicts the behavior of spring coupled actuators under various pre-stress levels. The model will be coupled with a SDOF model of a commercial nano-positioning stage (Nano-OP30, Mad City Labs) and is the basis for future control applications.
Download or read book Behavior and Mechanics of Multifunctional and Composite Materials 2007 written by Marcelo J. Dapino and published by SPIE-International Society for Optical Engineering. This book was released on 2007 with total page 738 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of SPIE present the original research papers presented at SPIE conferences and other high-quality conferences in the broad-ranging fields of optics and photonics. These books provide prompt access to the latest innovations in research and technology in their respective fields. Proceedings of SPIE are among the most cited references in patent literature.
Download or read book Modeling Design Testing and Control of a Two stage Actuation Mechanism Using Piezoelectric Actuators for Automotive Applications written by Vijay Anand Neelakantan and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: High bandwidth actuation systems capable of simultaneously producing relatively large forces and displacements are required for use in automobiles and other industrial applications. Conventional hydraulic actuation mechanisms used in automotive brakes and clutches are complex, inefficient and have poor control robustness. For instance, the hydraulic clutch actuation mechanism used in automatic transmissions requires pumping hardware that derives power from the engine. Along with inefficient torque converters these systems lead to reduced fuel economy, controllability issues and other disadvantages. Therefore, using advanced technologies to develop and implement novel devices, as replacements for the conventional hydraulic actuation mechanisms will improve the vehicle fuel economy significantly. This thesis presents the concept, design, development, modeling, testing and control of a novel two-stage hybrid actuation mechanism by combining classical actuators like DC motors and advanced smart material actuators like piezoelectric stack actuators. This two-stage mechanism takes advantage of the unique stiffness (force-stroke) characteristic of a typical clutch or a brake engagement process. This two-stage mechanism is modeled and designed by splitting the system into two operating regimes, namely the stroke phase and the force phase. Importance is placed on modeling the nonlinearities like the hysteresis property of piezoelectric actuators and techniques to overcome it using appropriate analysis and control methodologies. Also a technique to estimate force based on the charge stored in the piezoactuator is discussed, which leads to the elimination of the mechanical force sensor. A simple laboratory prototype experimental setup is built to demonstrate the system functioning and to test the different control strategies. A major part of this research includes the development of robust control methodologies using advanced concepts like Internal Model Control (IMC), Model Predictive Control (MPC) and a new strategy called Model Predictive Sliding Mode Control (MPSMC). The different control strategies are used to guide the two-stage actuation system to track time-varying reference force inputs. The IMC concept is used to develop a robust controller based on the uncertainty-bound on the system model. MPC is used to produce a sub-optimal controller that uses a receding-horizon window for future prediction of system behavior. The new concept MPSMC is developed to overcome the limitations of the conventional discrete-time sliding mode control. In this method, the system is forced to reach the sliding mode in a smooth sub-optimal trajectory. This optimization is carried out using MPC. Experimental results are highlighted in each case comparing the effectiveness of the different methods.
Download or read book Non linear Finite Element Modeling of THUNDER Piezoelectric Actuators written by Barmac K. Taleghani and published by . This book was released on 1999 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: A NASTRAN non-linear finite element model has been developed for predicting the dome heights of THUNDER (THin Layer UNimorph Ferroelectric DrivER) piezoceramic actuators. To analytically validate the finite element model, a comparison was made with a non-linear plate solution using Von Karmen's approximation. A 500 volt input was used to examine the actuator deformation. The NASTRAN finite element model was also compared with experimental results. Four groups of specimens were fabricated and tested. Four different input voltages, which included 120, 160, 200, and 240 Vp-p with a 0 volts offset, were used for this comparison.
Download or read book Piezoelectric Actuators written by Joshua E. Segel and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Piezoelectric actuators are simple structures with compact sizes that provide quick and precise responses to an electrical stimulus. The response of the piezoelectric actuator can be a mechanical displacement or a blocking force with the magnitude determined by the structure's geometry and the electromechanical properties of the materials used. This book presents topical research in the study of piezoelectric actuators. Topics discussed include thick-film piezoelectric actuators prepared by screen-printing; pressure control of vehicle ABS using piezoactuator-based valve modulators; ultrasonic actuators based on the Langevin transducer; the dynamics of hinged-hinged beam using piezoelectric absorbers and modelling and control of piezoelectric actuator systems.
