Mr. Ronny Calixto Carbonari Profile

Ronny Calixto Carbonari

at Escola Politecnica da USP

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Publications (6)

Proceedings Article | 18 April 2007 Paper

Piezoactuator design considering the optimum placement of FGM piezoelectric material

Ronny Carbonari, Shinji Nishiwaki, Glaucio Paulino, Emílio Nelli Silva

Proceedings Volume 6523, 65230C (2007) https://doi.org/10.1117/12.715411

KEYWORDS: Optimization (mathematics), Actuators, Dielectrics, Electrodes, Computer programming, Aluminum, Finite element methods, Manufacturing, Matrices, Instrument modeling

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Functionally Graded Materials (FGMs) possess continuous variation of material properties and are characterized by spatially varying microstructures. Recently, the FGM concept has been explored in piezoelectric materials to improve properties and to increase the lifetime of piezoelectric actuators. Elastic, piezoelectric, and dielectric properties are graded along the thickness of a piezoceramic FGM. Thus, the gradation of piezoceramic properties can influence the performance of piezoactuators, and an optimum gradation can be sought through optimization techniques. However, the design of these FGM piezoceramics are usually limited to simple shapes. An interesting approach to be investigated is the design of FGM piezoelectric mechanisms which essentially can be defined as a FGM structure with complex topology made of piezoelectric and non-piezoelectric material that must generate output displacement and force at a certain specified point of the domain and direction. This can be achieved by using topology optimization method. Thus, in this work, a topology optimization formulation that allows the simultaneous distribution of void and FGM piezoelectric material (made of piezoelectric and non-piezoelectric material) in the design domain, to achieve certain specified actuation movements, will be presented. The method is implemented based on the SIMP material model where fictitious densities are interpolated in each finite element, providing a continuum material distribution in the domain. The optimization algorithm employed is based on sequential linear programming (SLP) and the finite element method is based on the graded finite element concept where the properties change smoothly inside the element. This approach provides a continuum approximation of material distribution, which is appropriate to model FGMs. Some FGM piezoelectric mechanisms were designed to demonstrate the usefulness of the proposed method. Examples are limited to two-dimensional models, due to FGM manufacturing constraints and the fact that most of the applications for such FGM piezoelectric mechanisms are planar devices. An one-dimensional constraint of the material gradation is imposed to provide more realistic designs.

Proceedings Article | 27 March 2006 Paper

Optimum place of piezoelectric material in the piezoactuator design

Ronny Carbonari, Shinji Nishiwaki, Emílio Silva

Proceedings Volume 6166, 616608 (2006) https://doi.org/10.1117/12.658470

KEYWORDS: Actuators, Finite element methods, Electrodes, Aluminum, Ferroelectric materials, Optimization (mathematics), Dielectrics, Microelectromechanical systems, Structural design, Chemical elements

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Piezoelectric actuators offer significant promise in a wide range of applications. The piezoelectric actuators considered in this work essentially consist of a flexible structure actuated by piezoceramics that must generate output displacement and force at a certain specified point of the domain and direction. The flexible structure acts as a mechanical transformer by amplifying and changing the direction of piezoceramics output displacements. The design of these piezoelectric actuators are complex and a systematic design method, such as topology optimization has been successfully applied in the latest years, with appropriate formulation of the optimization problem to obtain optimized designs. However, in these previous design formulations, piezoceramics position are usually kept fixed in the design domain and only the flexible structure is designed by distributing only some non-piezoelectric material (Aluminum, for example). This imposes a constraint in the position of piezoelectric material in the optimization problem limiting the optimality of the solution. Thus, in this work, a formulation that allows the simultaneous search for an optimal topology of a flexible structure as well as the optimal positions of the piezoceramics in the design domain, to achieve certain specified actuation movements, will be presented. This can be achieved by allowing the simultaneous distribution of non-piezoelectric and piezoelectric material in the design domain. The optimization problem is posed as the design of a flexible structure together with optimum positions of piezoelectric material that maximizes output displacements or output forces in a certain specified direction and point of the domain. The method is implemented based on the SIMP material model where fictitious densities are interpolated in each finite element, providing a continuum material distribution in the domain. Presented examples are limited to two-dimensional models, once most of the applications for such piezoelectric actuators are planar devices.

Proceedings Article | 27 March 2006 Paper

Design of functionally graded piezoelectric actuators using topology optimization

Ronny Carbonari, Emílio Silva, Glaucio Paulino

Proceedings Volume 6166, 616607 (2006) https://doi.org/10.1117/12.658562

KEYWORDS: Actuators, Finite element methods, Optimization (mathematics), Dielectrics, Gold, Electrodes, Computer programming, Matrices, Systems modeling, Composites

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Proceedings Article | 27 March 2006 Paper

Multi-actuated functionally graded piezoelectric micro-tools design using topology optimization

Ronny Carbonari, Emílio Silva, Glaucio Paulino

Proceedings Volume 6166, 616609 (2006) https://doi.org/10.1117/12.658503

KEYWORDS: Ferroelectric materials, Electrodes, Dielectrics, Finite element methods, Aluminum, Actuators, Solids, Matrices, Microsurgery, Optimization (mathematics)

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The micro-tools considered in this work consist essentially of multi-flexible structures actuated by two or more piezoceramic devices that must generate different output displacements and forces at different specified points of the domain and on different directions. The multiflexible structure acts as a mechanical transformer by amplifying and changing the direction of the piezoceramics output displacements. Micro-tools offer significant promise in a wide range of applications such as cell manipulation, microsurgery, and micro/nanotechnology processes. Although the design of these micro-tools is complicated due to the coupling among movements generated by various piezoceramics, it can be realized by means of topology optimization concepts. Recently, the concept of functionally graded materials (FGMs) has been explored in piezoelectric materials to improve performance and increase lifetime of piezoelectric actuators. Usually for an FGM piezoceramic, elastic, piezoelectric, and dielectric properties are graded along the thickness. Thus, the objective of this work is to study the influence of piezoceramic property gradation in the design of the multiflexible structures of piezoelectric micro-tools using topology optimization. The optimization problem is posed as the design of a flexible structure that maximizes different output displacements or output forces in different specified directions and points of the domain, in response to different excited piezoceramic portions: while minimizing the effects of movement coupling. The method is implemented based on the solid isotropic material with penalization (SIMP) model where fictitious densities are interpolated in each finite element, providing a continuum material distribution in the domain. As examples, designs of a single piezoactuator and an XY nano-positioner actuated by two FGM piezoceramics are considered. The resulting designs are compared with designs considering homogeneous piezoceramics. The present examples are limited to two-dimensional models because most of the applications for such micro-tools are planar devices.

Proceedings Article | 17 May 2005 Paper

Experimental and numerical characterization of multi-actuated piezoelectric device designs using topology optimization

Ronny Calixto Carbonari, Gilder Nader, Shinji Nishiwaki, Emilio Carlos Nelli Silva

Proceedings Volume 5764, (2005) https://doi.org/10.1117/12.599737

KEYWORDS: Finite element methods, Computer aided design, Manufacturing, Laser interferometry, Prototyping, Interferometers, Aluminum, Structural design, Instrument modeling, Optimization (mathematics)

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Proceedings Article | 26 July 2004 Paper

Topology optimization applied to the design of multiactuated piezoelectric microtools

Ronny Carbonari, Emilio Nelli Silva, Shinji Nishiwaki

Proceedings Volume 5383, (2004) https://doi.org/10.1117/12.538584

KEYWORDS: Finite element methods, Optimization (mathematics), Chemical elements, Microelectromechanical systems, Manufacturing, Electrodes, Actuators, 3D modeling, Microsurgery, Nanotechnology

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