Analytical Modeling and Simulation of S-Drive Piezoelectric Actuators

This paper presents a structural geometry for increasing piezoelectric deformation, which is suitable for both micro- and macro-scale applications. New and versatile microstructure geometries for actuators can improve device performance, and piezoelectric designs benefit from a high-frequency response, power density, and efficiency, making them a viable choice for a variety of applications. Previous works have presented piezoelectric structures capable of this amplification, but few are well-suited to planar manufacturing. In addition to this manufacturing difficulty, a large number of designs cannot be chained into longer elements, preventing them from operating at the macro-scale. By optimizing for both modern manufacturing techniques and composability, this structure excels as an option for a variety of macro- and micro-applications. This paper presents an analytical compact model of a novel dual-bimorph piezoelectric structure, and shows that this compact model is within 2% of a computer-distributed element model. Furthermore it compares the actuator’s theoretical performance to that of a modern actuator, showing that this actuator trades mechanical efficiency for compactness and weight savings.

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Development of 3D Finite Element Model for Predicting Process-Induced Defects in Additive Manufacturing by Selective Laser Melting (SLM)

Volume 2: Advanced Manufacturing ◽

10.1115/imece2016-66245 ◽

2016 ◽

Author(s):

Bilal Hussain ◽

A. Sherif El-Gizawy

Keyword(s):

Additive Manufacturing ◽

Laser Beam ◽

Selective Laser Melting ◽

Thermal Stresses ◽

Cost Effective ◽

Element Model ◽

Laser Melting ◽

Two Phase ◽

Free Process ◽

Manufacturing Techniques

Selective Laser Melting (SLM) is one of the important Additive Manufacturing techniques for building functional products. Nevertheless, the absence of accurate models for predicting the SLM process behavior, delays development of cost effective and defects free process. This work presents a coupled thermo-mechanical numerical model to capture the two phase (solid-liquid) solidification melting phenomena that occur in the process. The proposed model will also predict the evolvement of process-induced properties and defects particularly residual stresses caused by temperature gradient and thermal stresses. CO2 or Nd:YAG laser beam can be used as a heat source with a Gaussian distribution for the laser beam energy.

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Modern Manufacturing Techniques

Manufacturing Engineering and Materials Processing - Manufacturing ◽

10.1201/9780203911204.ch9 ◽

2003 ◽

Keyword(s):

Modern Manufacturing ◽

Manufacturing Techniques

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Pore design and engineering for filters and membranes

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2005.1690 ◽

2005 ◽

Vol 364 (1838) ◽

pp. 161-174 ◽

Cited By ~ 41

Author(s):

Richard Holdich ◽

Serguei Kosvintsev ◽

Iain Cumming ◽

Sergey Zhdanov

Keyword(s):

Experimental Data ◽

Fluid Flow ◽

Pore Size ◽

Suspended Material ◽

Slot Length ◽

Depth Filtration ◽

Flow Through ◽

Pore Flow ◽

Modern Manufacturing ◽

Manufacturing Techniques

In filtration, the concept of pore size is not easy to define. In microfiltration, there are numerous advantages in employing a surface filtering membrane, rather than one relying on depth filtration mechanisms from a tortuous pore flow channel. Modern manufacturing techniques provide means to produce surface filtering membranes. For filtration, it is shown that a suitable pore design is an array of long thin slots. An analysis of fluid flow through the slots suggests that a short slot is adequate, but experimental data with suspended material indicates that slot length is important. Using long slots and careful control of the flow through the membrane it is possible to filter deforming particles such as oil drops from water.

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Modelling of 4H-SiC VJFETs with Self-Aligned Contacts

Materials Science Forum ◽

10.4028/www.scientific.net/msf.858.913 ◽

2016 ◽

Vol 858 ◽

pp. 913-916 ◽

Cited By ~ 3

Author(s):

Konstantinos Zekentes ◽

Konstantin Vassilevski ◽

Antonis Stavrinidis ◽

George Konstantinidis ◽

Maria Kayambaki ◽

...

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Analytical Model ◽

Element Model ◽

Experimental Results ◽

Compact Model ◽

Channel Lengths ◽

The Finite Element Model

Purely vertical 4H-SiC JFETs have been modeled by using three different approaches: the analytical model, the finite element model and the compact model. The results of the modeling have been compared with experimental results on a series of fabricated self-aligned devices with two different channel lengths (0.3 and 1.1μm) and various channel widths (1.5, 2, 2.5, 3, 4 and 5 μm). For all the considered models I-V and C-V characteristics could be satisfactorily simulated.

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Contact characteristic analysis of spindle–toolholder joint at high speeds based on the fractal model

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/0954408916652648 ◽

2016 ◽

Vol 231 (5) ◽

pp. 1025-1036 ◽

Cited By ~ 1

Author(s):

Yongsheng Zhao ◽

Jingjing Xu ◽

Ligang Cai ◽

Weimin Shi ◽

Zhifeng Liu ◽

...

Keyword(s):

Finite Element ◽

Hybrid Model ◽

Contact Stiffness ◽

Element Model ◽

Fractal Model ◽

Contact Ratio ◽

Characteristic Analysis ◽

Micro Scale ◽

High Speeds ◽

Macro Scale

Due to the influence of centrifugal force, accurate contact stiffness model of spindle–toolholder joint at high speeds is crucial in predicting the dynamic behavior and chatter vibration of spindle–toolholder system. In this paper, a macro–micro scale hybrid model is presented to obtain the contact stiffness of spindle–toolholder joint in high speeds. The hybrid model refers to the finite element model in macro-scale and three-dimensional fractal model in micro-scale. The taper contact surface of spindle–toolholder joint is assumed flat in macro-scale and the finite element method is used to obtain the pressure distribution at different speeds. In micro-scale, the topography of contact surfaces is fractal featured and determined by fractal parameters. Asperities in micro-scale are considered as elastic and plastic deformation. Then, the contact ratio, radial and torsional contact stiffness of spindle–toolholder joint can be calculated by integrating the micro asperities. Experiments with BT40 type toolholder–spindle assembly are conducted to verify the proposed model in the case of no speed. The reasonable intervals of spindle speed and drawbar force can be obtained based on the presented hybrid model, which will provide theoretical basis for the application and optimization of the spindle–toolholder system.

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Characteristics of Modern Manufacturing Techniques

AMST’05 Advanced Manufacturing Systems and Technology - CISM International Centre for Mechanical Sciences ◽

10.1007/3-211-38053-1_2 ◽

2007 ◽

pp. 5-15 ◽

Cited By ~ 1

Author(s):

H. Schulz

Keyword(s):

Modern Manufacturing ◽

Manufacturing Techniques

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Reliability-based topology optimization of piezoelectric smart structures with voltage uncertainty

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x211072197 ◽

2022 ◽

pp. 1045389X2110721

Author(s):

Bo Yang ◽

Changzheng Cheng ◽

Xuan Wang ◽

Zeng Meng ◽

Abbas Homayouni-Amlashi

Keyword(s):

Topology Optimization ◽

Reliability Analysis ◽

Optimization Method ◽

Polarization Model ◽

Loop Optimization ◽

Design Variables ◽

Index Approach ◽

Piezoelectric Structure ◽

Reliability Constraint ◽

Piezoelectric Structures

Currently, most of the piezoelectric structures are designed under deterministic conditions, where the influence of uncertain factors on the output motion accuracy is ignored. In this work, a probabilistic reliability-based topology optimization method for piezoelectric structure is proposed to deal with the working voltage uncertainty. A nested double-loop optimization algorithm of minimizing the total volume while satisfying the reliability requirement of the displacement performance is established, where the PEMAP-P (piezoelectric material with penalization and polarization) model is used for parameterization of stiffness matrix, piezoelectric coupling matrix, and polarization direction. This strategy consists of an inner loop for reliability analysis and an outer loop for topology optimization. The reliability index approach based on most probable point (MPP) is used for realizing the evaluation of reliability constraint in reliability analysis. The sensitivities of reliability constraint with respect to the random variables and design variables are detailed using the adjoint variable method. Typical examples are performed to illustrate the effectiveness of the proposed RBTO method. A comparison of the optimization results for different reliability indexes, standard deviations of the voltage, spring stiffnesses, and displacement limits are conducted, as well as the deterministic topology optimization results.

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Computational Coupled Method for Multiscale and Phase Analysis

Journal of Engineering Materials and Technology ◽

10.1115/1.4023776 ◽

2013 ◽

Vol 135 (2) ◽

Cited By ~ 3

Author(s):

Moonho Tak ◽

Duhee Park ◽

Taehyo Park

Keyword(s):

Element Model ◽

Discrete Element ◽

Multiscale Methods ◽

Contact Forces ◽

Multiscale Approach ◽

Theoretical Approaches ◽

Macro Scale ◽

Coupling Algorithms ◽

Coupling Algorithm ◽

Element Method

On micro scale the constitutions of porous media are effected by other constitutions, so their behaviors are very complex and it is hard to derive theoretical formulations as well as to simulate on macro scale. For decades, in order to escape this complication, the phenomenological approaches in a field of multiscale methods have been extensively researched by many material scientists and engineers. Their theoretical approaches are based on the hierarchical multiscale methods using a priori knowledge on a smaller scale; however it has a drawback that an information loss can be occurred. Recently, according to a development of the core technologies of computer, the ways of multiscale are extended to a direct multiscale approach called the concurrent multiscale method. This approach is not necessary to deal with complex mathematical formulations, but it is noted as an important factor: development of computational coupling algorithms between constitutions in a porous medium. In this work, we attempt to develop coupling algorithms in different numerical methods finite element method (FEM), smoothed particle hydrodynamics (SPH) and discrete element method (DEM). Using this coupling algorithm, fluid flow, movement of solid particle, and contact forces between solid domains are computed via proposed discrete element which is based on SPH, FEM, and DEM. In addition, a mixed FEM on continuum level and discrete element model with SPH particles on discontinuum level is introduced, and proposed coupling algorithm is verified through numerical simulation.

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Multi-Phase Microstructures for Materials with Extreme Bulk Modulus or Thermal Conductivity

Materials Science Forum ◽

10.4028/www.scientific.net/msf.909.306 ◽

2017 ◽

Vol 909 ◽

pp. 306-310

Author(s):

Arash Radman ◽

Xiao Dong Huang ◽

Mike Xie

Keyword(s):

Thermal Conductivity ◽

Finite Element ◽

Element Model ◽

Homogenization Theory ◽

Topological Design ◽

Evolutionary Structural Optimization ◽

Macro Scale ◽

Constituent Phase ◽

Cost Efficient ◽

Multi Phase

This paper describes a methodology based on “Bidirectional Evolutionary Structural Optimization” (BESO) for topological design of microstructures of materials with more than two constituent phases. The composite material is made by repeating microstructures known as periodic base cells. The aim is to achieve appropriate topology of microstructure phases that enhances the material’s bulk or thermal conductivity performance in macro-scale. Constituent phases are divided into some groups and by performing finite element analyses on microstructure, sensitivity numbers are calculated with the application of Homogenization theory. Properties of elements are gradually changed in the finite element model based on their sensitivity numbers and controlling volume of each constituent phase in the model. Some sample microstructures are generated and presented to show the capability of the approach. The results indicate that the proposed approach is very cost efficient. Moreover, there are distinctive boundaries between the constituent phases in the generated microstructures; which is an inherent advantage of application of BESO approach.

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