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

2010 ◽  
Vol 154-155 ◽  
pp. 1705-1712 ◽  
Author(s):  
Mohsen Hamedi ◽  
Milad Vismeh ◽  
Parisa Salimi
Keyword(s):  
Thin Layer ◽  
Active Material ◽  
Input Voltage ◽  
Rotary Table ◽  
Design Strategies ◽  
Temperature Dependent ◽  
Finite Element Software ◽  
Simulation Procedure ◽  
Shape Structure ◽  
Assembly Unit

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 <100> 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.

Modeling of Thermoplastic Materials for the Process-Simulation of Press-Fit Interconnections on Moulded Interconnected Devices

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Thomas Fellner ◽  
Elena Zukowski ◽  
Jürgen Wilde ◽  
H. Kück ◽  
H. Richter ◽  
...  
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Base Material ◽  
Creep Model ◽  
Assembly Process ◽  
Temperature Dependent ◽  
Reliability Modeling ◽  
Finite Element Software ◽  
Press Fit ◽  
Temperature Loads

This investigation is aimed at the modeling of both the fabrication process and the reliability of press-fit interconnections on moulded interconnect devices (MID). These are multifunctional three-dimensional substrates, produced by thermoplastic injection moulding for large-series applications. The assembly process and subsequently the durability of press-fit interconnections has been modeled and proved with a finite element software. Especially, a simulation tool for process optimizations was created and applied. In order to obtain realistic results, a creep model for the investigated base material, a liquid-crystal polymer (LCP), was generated and verified by experiments. Required friction coefficients between metal pin and base material were determined by adapting simulations and experiments. Retention forces of pins pressed into substrate holes during as well after the assembly process, and after temperature loads were predicted by simulations. Additionally, the decreasing extraction forces over time due to creep in the thermoplastic base material have been predicted for different storage temperatures as well with finite element analyses. Following, the numerical results of the process and reliability modeling were verified by experiments. It is concluded that the behavior of the mechanical contact of the pin-substrate system, can be suitably described time- and temperature-dependent.

scholarly journals Macromolecular Design Strategies for Preventing Active‐Material Crossover in Non‐Aqueous All‐Organic Redox‐Flow Batteries

2017 ◽  
Vol 56 (6) ◽  
pp. 1595-1599 ◽  
Author(s):  
Sean E. Doris ◽  
Ashleigh L. Ward ◽  
Artem Baskin ◽  
Peter D. Frischmann ◽  
Nagarjuna Gavvalapalli ◽  
...  
Keyword(s):  
Active Material ◽  
Design Strategies ◽  
Redox Flow Batteries ◽  
Flow Batteries

scholarly journals Thermo-Mechanical Modeling of Distortions Promoted during Cooling of Ti-6Al-4V Part Produced by Superplastic Forming

2016 ◽  
Vol 838-839 ◽  
pp. 196-201
Author(s):  
Maxime Rollin ◽  
Vincent Velay ◽  
Luc Penazzi ◽  
Thomas Pottier ◽  
Thierry Sentenac ◽  
...  
Keyword(s):  
Finite Element ◽  
Thermal Stresses ◽  
Superplastic Forming ◽  
Model Material ◽  
Material Behavior ◽  
Mechanical Modeling ◽  
Temperature Dependent ◽  
Finite Element Software ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

In AIRBUS, most of the complex shaped titanium fairing parts of pylon and air inlets are produced by superplastic forming (SPF). These parts are cooled down after forming to ease their extraction and increase the production rate, but AIRBUS wastes a lot of time to go back over the geometric defects generated by the cooling step. This paper investigates the simulations of the SPF, cooling and clipping operations of a part on Abaqus® Finite element software. The different steps of the global process impact the final distortions. SPF impacts the thickness and the microstructure/behavior of material, cooling impacts also the microstructure/behavior of material and promotes distortions through thermal stresses and finally, clipping relaxes the residual stresses of the cut part. An elastic-viscoplastic power law is used to model material behavior during SPF and a temperature dependent elastic perfectly plastic model for the cooling and clipping operations.

Dynamics of cooling domes of viscoplastic fluid

2000 ◽  
Vol 422 ◽  
pp. 225-248 ◽  
Author(s):  
N. J. BALMFORTH ◽  
R. V. CRASTER
Keyword(s):  
Thin Layer ◽  
Yield Stress ◽  
Stability Theory ◽  
Constitutive Relations ◽  
Linear Stability Theory ◽  
Viscoplastic Fluid ◽  
Surface Cooling ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Dependent Viscosity

A non-isothermal viscoplastic thin-layer theory is developed to explore the effects of surface cooling, yield stress, and shear thinning on the evolution of non-isothermal domes of lava and laboratory fluids. The fluid is modelled using the Herschel–Bulkley constitutive relations, but modified to have temperature-dependent viscosity and yield stress. The thin-layer equations are solved numerically to furnish models of expanding, axisymmetrical domes. Linear stability theory reveals the possibility of non-axisymmetrical, fingering-like instability in these domes. Finally, the relevance to lava and experiments is discussed.

The mechanical effects of deposition patterns in welding-based layered manufacturing

2007 ◽  
Vol 221 (10) ◽  
pp. 1499-1509 ◽  
Author(s):  
M P Mughal ◽  
R A Mufti ◽  
H Fawad
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Three Dimensional ◽  
Layered Manufacturing ◽  
Source Material ◽  
Structural Effects ◽  
Temperature Dependent ◽  
Deposition Patterns ◽  
Finite Element Software ◽  
The One

This paper presents a finite element (FE)-based three-dimensional analysis to study the structural effects of deposition patterns in welding-based layered manufacturing (LM). A commercial finite element software ANSYS is used to simulate the deposition incorporating a double ellipsoidal heat source, material addition, and temperature-dependent material properties. Simulations carried out with various deposition sequences revealed that the thermal and structural effects on the workpiece are different for different patterns. The sequence starting from outside and ending at the centre is identified as the one which produces minimum warpage.

scholarly journals Simplified approach for simulating hermetic compressor startup regime

2021 ◽  
pp. 13-28
Author(s):  
Eduardo P Falcetti ◽  
Álvaro Gardenghi ◽  
Alvaro B Dietrich ◽  
Luben Cabezas-Gómez
Keyword(s):  
Simple Model ◽  
Angular Velocity ◽  
Electric Motor ◽  
Numerical Technique ◽  
Input Voltage ◽  
Oil Viscosity ◽  
Simplified Approach ◽  
Simulation Procedure ◽  
Transient Data ◽  
Hermetic Compressor

It is presented a hermetic compressor startup simulation procedure considering a simplified approach to obtain the transient data of different compressor parameters. The main numerical technique is a four order Runge-Kutta procedure to numerically integrate the systems of ordinary differential equations, which describe the variables’ variation with time in each part of the compressor. The simulations were performed in the Windali software. The results show how the oil viscosity influences the electrical motor torque, the compressor load and crankshaft angular velocity with time for two electric motor input voltage values. The increase of oil viscosity by a factor of 2, retards the compressor startup for more than one second. The presented simple model could be valuable for studying the geometrical and operational influence on compressor startup.

scholarly journals The nature of the ϒ-rays excited by β-rays

1912 ◽  
Vol 86 (590) ◽  
pp. 513-529 ◽  
Keyword(s):  
Thin Layer ◽  
Active Material ◽  
Atomic Weight ◽  
Detailed Account ◽  
Active Matter ◽  
Small Space ◽  
Lead Sulphate

In a previous paper, it was shown that the β -rays of radium E excited ϒ-rays in different materials, the amount increasing with the atomic weight of the substance used. It was found that the ϒ -radiation was largely increased when the β -rays fell on a lead screen suitably placed, and as the active material, radium (D + E + F), was mixed with lead sulphate confined in a small space, it was obvious that some, if not all, of the ϒ -radiation issuing from the mixture was due to ϒ -rays excited by β -rays in the lead impurity. It thus seemed possible that no primary ϒ -rays were emitted by radium E. By using a more suitable source, in which the active material was spread in a thin layer over biter paper, it has been found that a primary ϒ -radiation is emitted from the active matter. This radiation, however, is much sorter than that excited by the β -rays in lead. more detailed account of these primary rays will be given later.

Sign in / Sign up

Export Citation Format

Share Document