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Papers by Parisa Salimi

Research paper thumbnail of Displacement Amplification of Electrostatically-Driven Microgripper in a Hybrid Design with Electrothermal Actuation

Advanced Materials Research, 2010

By the growing development of micro electromechanical systems, the application of microgrippers f... more By the growing development of micro electromechanical systems, the application of microgrippers for handling and assembling of microparts attracts more attention. In this paper, an electrostatic microgripper using comb drive mechanism is designed and a formulation is presented to predict the critical voltage for pull-in instability threshold. Then the advantages of a modified model of electrothermal U-shape actuator with large forces and bilateral displacement are utilized to amplify the output displacement range of microgripper prongs. To show this amplification, finite element simulations are performed on the primary and modified microgripper proposed models.

Research paper thumbnail of A New MEMS Assembly Unit for Hybrid Self Micropositioning and Forced Microclamping of Submilimeter Parts

Advanced Materials Research, 2010

ABSTRACT In this paper we have presented an assembly unit equipped with electrothermally actuated... more ABSTRACT In this paper we have presented an assembly unit equipped with electrothermally actuated microclamps (MCs), piezoelectric pad and rotary table to provide an environment for micropositioning and microclamping of submilimeter parts. The structural material of the system is considered to be oriented Si with 20 µm thickness. Activating MCs, two approaches performed in the simulation procedure and results showed that utilizing 140 nm deposited Chromium thin layer on the U-shape structure as active material, reduces the overall input voltage and temperature in comparison with direct applying of potential difference to Si structure. To obtain more realistic results, both of these methods are simulated using finite element software in line with considering temperature-dependent thermophysical properties for structural and active material due to high operating temperatures. Design strategies and other advantages of using thin layer of chromium as active material are highlighted in the text.

Research paper thumbnail of Design, analysis and fabrication of silicon microfixture with electrothermal microclamp cell

Microelectronic Engineering, 2013

Micro handling devices that are extensively utilized for microfixturing operations are of great i... more Micro handling devices that are extensively utilized for microfixturing operations are of great interest to the researches for investigating their mechanism and actuation principles. Number of microparts that can be handled simultaneously is an important parameters determining efficiency of the microfixture device. However this issue is not sufficiently addressed in the published literature. This paper discusses a microfixturing system equipped with electrothermally actuated microclamps (ETMC) which is used for positioning microparts. The design comprises microclamps on a rotary table, vibrated with random motion through piezoelectric actuation. Each microclamp is composed of two u-shape microactuators which are configured symmetrically to clamp microparts from their sides. Functionality of the microgrippers for submillimeter parts is analytically modeled and simulated using finite element analysis method. The system is then fabricated and experiments are performed to measure variation of microclamp displacement with input voltage change. Comparing analytical and numerical results with the measured values validates the analytical model and simulation results. The microfixture is assembled and its practicality for positioning and clamping microparts is realized.

Research paper thumbnail of Simulation and experimental investigation of a novel electrostatic microgripper system

A thermo-mechanical simulation of the friction stir processing (FSP), using the DEFORM 3D softwar... more A thermo-mechanical simulation of the friction stir processing (FSP), using the DEFORM 3D software based on Lagrangian implicit, was developed and verified by the experimental results. Simulation can successfully predict the temperature and effective strain distributions. Material flow around the tool pin was examined using the point tracking. It was found that the major part of material flow occurs at the advancing side, and consequently, stirred zone (SZ) stretches toward the advancing side. However, material at the retreating side moves slightly in backward direction. The material deformation and the peak temperature influence on the microstructural characters and can determine the width of SZ. Based on the simulation, effective strain and temperature histories of material around the tool pin were also calculated. The amount of effective strain and peak temperature required for recrystallization at the advancing and retreating sides as well as at the bottom of SZ was determined. Therefore, the width of SZ can be predicted by the simulation.

Research paper thumbnail of Displacement Amplification of Electrostatically-Driven Microgripper in a Hybrid Design with Electrothermal Actuation

Advanced Materials Research, 2010

By the growing development of micro electromechanical systems, the application of microgrippers f... more By the growing development of micro electromechanical systems, the application of microgrippers for handling and assembling of microparts attracts more attention. In this paper, an electrostatic microgripper using comb drive mechanism is designed and a formulation is presented to predict the critical voltage for pull-in instability threshold. Then the advantages of a modified model of electrothermal U-shape actuator with large forces and bilateral displacement are utilized to amplify the output displacement range of microgripper prongs. To show this amplification, finite element simulations are performed on the primary and modified microgripper proposed models.

Research paper thumbnail of A New MEMS Assembly Unit for Hybrid Self Micropositioning and Forced Microclamping of Submilimeter Parts

Advanced Materials Research, 2010

ABSTRACT In this paper we have presented an assembly unit equipped with electrothermally actuated... more ABSTRACT In this paper we have presented an assembly unit equipped with electrothermally actuated microclamps (MCs), piezoelectric pad and rotary table to provide an environment for micropositioning and microclamping of submilimeter parts. The structural material of the system is considered to be oriented Si with 20 µm thickness. Activating MCs, two approaches performed in the simulation procedure and results showed that utilizing 140 nm deposited Chromium thin layer on the U-shape structure as active material, reduces the overall input voltage and temperature in comparison with direct applying of potential difference to Si structure. To obtain more realistic results, both of these methods are simulated using finite element software in line with considering temperature-dependent thermophysical properties for structural and active material due to high operating temperatures. Design strategies and other advantages of using thin layer of chromium as active material are highlighted in the text.

Research paper thumbnail of Design, analysis and fabrication of silicon microfixture with electrothermal microclamp cell

Microelectronic Engineering, 2013

Micro handling devices that are extensively utilized for microfixturing operations are of great i... more Micro handling devices that are extensively utilized for microfixturing operations are of great interest to the researches for investigating their mechanism and actuation principles. Number of microparts that can be handled simultaneously is an important parameters determining efficiency of the microfixture device. However this issue is not sufficiently addressed in the published literature. This paper discusses a microfixturing system equipped with electrothermally actuated microclamps (ETMC) which is used for positioning microparts. The design comprises microclamps on a rotary table, vibrated with random motion through piezoelectric actuation. Each microclamp is composed of two u-shape microactuators which are configured symmetrically to clamp microparts from their sides. Functionality of the microgrippers for submillimeter parts is analytically modeled and simulated using finite element analysis method. The system is then fabricated and experiments are performed to measure variation of microclamp displacement with input voltage change. Comparing analytical and numerical results with the measured values validates the analytical model and simulation results. The microfixture is assembled and its practicality for positioning and clamping microparts is realized.

Research paper thumbnail of Simulation and experimental investigation of a novel electrostatic microgripper system

A thermo-mechanical simulation of the friction stir processing (FSP), using the DEFORM 3D softwar... more A thermo-mechanical simulation of the friction stir processing (FSP), using the DEFORM 3D software based on Lagrangian implicit, was developed and verified by the experimental results. Simulation can successfully predict the temperature and effective strain distributions. Material flow around the tool pin was examined using the point tracking. It was found that the major part of material flow occurs at the advancing side, and consequently, stirred zone (SZ) stretches toward the advancing side. However, material at the retreating side moves slightly in backward direction. The material deformation and the peak temperature influence on the microstructural characters and can determine the width of SZ. Based on the simulation, effective strain and temperature histories of material around the tool pin were also calculated. The amount of effective strain and peak temperature required for recrystallization at the advancing and retreating sides as well as at the bottom of SZ was determined. Therefore, the width of SZ can be predicted by the simulation.

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