scholarly journals Micro Motion Amplifiers for Compact Out-of-Plane Actuation

Micromachines ◽  
2018 ◽  
Vol 9 (7) ◽  
pp. 365 ◽  
Author(s):  
Xin Xie ◽  
Majid Bigdeli Karimi ◽  
Sanwei Liu ◽  
Battushig Myanganbayar ◽  
Carol Livermore
Keyword(s):  
Microelectromechanical Systems ◽  
Unit Area ◽  
Small Scale ◽  
Out Of Plane ◽  
Micro Motion ◽  
Tactile Interfaces ◽  
Flexural Hinges ◽  
Work Done ◽  
Assembly Error ◽  
Force Displacement

Small-scale, out-of-plane actuators can enable tactile interfaces; however, achieving sufficient actuator force and displacement can require larger actuators. In this work, 2-mm2 out-of-plane microactuators were created, and were demonstrated to output up to 6.3 µm of displacement and 16 mN of blocking force at 170 V. The actuators converted in-plane force and displacement from a piezoelectric extensional actuator into out-of-plane force and displacement using robust, microelectromechanical systems (MEMS)-enabled, half-scissor amplifiers. The microscissors employed two layers of lithographically patterned SU-8 epoxy microstructures, laminated with a thin film of structural polyimide and adhesive to form compact flexural hinges that enabled the actuators’ small area. The self-aligned manufacture minimized assembly error and fabrication complexity. The scissor design dominated the actuators’ performance, and the effects of varying scissor angle, flexure thickness, and adhesive type were characterized to optimize the actuators’ output. Reducing the microscissor angle yielded the highest actuator performance, as it maximized the amplification of the half-scissor’s displacement and minimized scissor deformation under externally applied loads. The actuators’ simultaneously large displacements and blocking forces for their size were quantified by a high displacement-blocking force product per unit area of up to 50 mN·µm/mm2. For a linear force–displacement relationship, this corresponds to a work done per unit area of 25 mN·µm/mm2.

Design and Experimental Results of Small-Scale Rotary Engines

2001 ◽  
Author(s):  
Kelvin Fu ◽  
Aaron J. Knobloch ◽  
Fabian C. Martinez ◽  
David C. Walther ◽  
Carlos Fernandez-Pello ◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Microelectromechanical Systems ◽  
Combustion Engine ◽  
Lithium Ion ◽  
Internal Combustion ◽  
Specific Power ◽  
Small Scale ◽  
Efficient Operation ◽  
Rotary Engine ◽  
Rotary Engines

Abstract A research project is currently underway to develop small-scale internal combustion engines fueled by liquid hydrocarbons. The ultimate goal of the MEMS Rotary Internal Combustion Engine Project is to develop a liquid hydrocarbon fueled MEMS-size rotary internal combustion micro-engine capable of delivering power on the order of milli-watts. This research is part of a larger effort to develop a portable, autonomous power generation system with an order of magnitude improvement in energy density over alkaline or lithium-ion batteries. The rotary (Wankel-type) engine is well suited for the fabrication techniques developed in the integrated chip (IC) community and refined by the MicroElectroMechanical Systems (MEMS) field. Features of the rotary engine that lend itself to MEMS fabrication are its planar construction, high specific power, and self-valving operation. The project aims at developing a “micro-rotary” engine with an epitrochoidal-shaped housing under 1 mm3 in size and with a rotor swept volume of 0.08 mm3. To investigate engine behavior and design issues, larger-scale “mini-rotary” engines have been fabricated from steel. Mini-rotary engine chambers are approximately 1000 mm3 to 1700 mm3 in size and their displacements range from 78 mm3 to 348 mm3. A test bench for the mini-rotary engine has been developed and experiments have been conducted with gaseous-fueled mini-rotary engines to examine the effects of sealing, ignition, design, and thermal management on efficiency. Preliminary testing has shown net power output of up to 2.7 W at 9300 RPM. Testing has been performed using hydrogen-air mixtures and a range of spark and glow plug designs as the ignition source. Iterative design and testing of the mini-engine has lead to improved sealing designs. These particular designs are such that they can be incorporated into the fabrication of the micro-engine. Design and fabrication of a first generation meso-scale rotary engine has been completed using a SiC molding process developed at Case Western Reserve University. The fabrication of the micro-rotary engine is being conducted in U.C. Berkeley’s Microfabrication Laboratory. Testing of the mini-engine has lead to the conclusion that there are no fundamental phenomena that would prevent the operation of the micro-engine. However, heat loss and sealing issues are key for efficient operation of the micro-engine, and they must be taken into account in the design and fabrication of the micro-rotary engine. The mini-rotary engine design, testing, results and applications will be discussed in this paper.

Energy exchanges during indentation tests in fresh-water ice

1991 ◽  
Vol 15 ◽  
pp. 247-253
Author(s):  
Devinder S. Sodhi
Keyword(s):  
Experimental Data ◽  
Heat Dissipation ◽  
Graphical Form ◽  
Small Scale ◽  
Water Ice ◽  
Structure Interaction ◽  
First Law Of Thermodynamics ◽  
Indentation Tests ◽  
Energy Exchanges ◽  
Work Done

The data from a small-scale experimental study on ice-structure interaction are used to compute the energy exchanges that take place during creep deformation and intermittent and continuous crushing of ice. The energy supplied by the carriage is partly stored in the structural spring, partly converted to kinetic energy, partly dissipated in deforming and extruding the ice and partly dissipated as heat in the damping mechanisms of the structure. Except for the heat dissipation, all other forms of energy were computed from the experimental data, and the heat dissipation was computed from the energy balance using the first law of thermodynamics. Plots of all forms of energy are shown in graphical form, in which their relative magnitudes, times of occurrence and interplay can be seen. The main result of this study is the thesis that intermittent crushing or ice-induced vibration takes place whenever there is an imbalance between the rates of work done by the carriage and the indentor and that there are no vibrations when these rates of work are equal.

Microsurgical Devices by Pop-Up Book MEMS

2013 ◽  
Author(s):  
Joshua B. Gafford ◽  
Samuel B. Kesner ◽  
Robert J. Wood ◽  
Conor J. Walsh
Keyword(s):  
Lap Joints ◽  
Small Scale ◽  
Flexible Hinge ◽  
Final Weight ◽  
Out Of Plane ◽  
Return Spring ◽  
Torsional Loads ◽  
Manufacturing Techniques ◽  
Traditional Manufacturing ◽  
Electrical Components

The small scale of microsurgery poses significant challenges for developing robust and dexterous tools to grip, cut, and join sub-millimeter structures such as vessels and nerves. The main limitation is that traditional manufacturing techniques are not optimized to create smart, articulating structures in the 0.1–10 mm scale. Pop-up book MEMS is a new fabrication technology that promises to overcome this challenge and enable the monolithic fabrication of complex, articulated structures with an extensive catalog of materials, embedded electrical components, and automated assembly with feature sizes down to 20 microns. In this paper, we demonstrate a proof-of-concept microsurgical gripper and evaluate its performance at the component and device level to characterize its strength and robustness. 1-DOF Flexible hinge joints that constrain motion and allow for out-of-plane actuation were found to resist torsional loads of 22.8±2.15 N·mm per mm of hinge width. Adhesive lap joints that join individual layers in the laminate structure demonstrated a shear strength of 26.8±0.53 N/mm2. The laminate structures were also shown to resist peel loads of 0.72±0.10 N/mm2. Various flexible hinge and adhesive lap components were then designed into an 11-layered structure which ‘pops up’ to realize an articulating microsurgical gripper that includes a cable-driven mechanism for gripping actuation and a flexural return spring to passively open the gripper. The gripper prototype, with final weight of 200 mg, overall footprint of 18 mm by 7.5 mm, and features as small as 200 microns, is able to deftly manipulate objects 100 times is own weight at the required scale, thus demonstrating its potential for use in microsurgery.

Steric Interaction of Fluid Membranes in Multilayer Systems

1978 ◽  
Vol 33 (3) ◽  
pp. 305-315 ◽  
Author(s):  
W. Helfrich
Keyword(s):  
Unit Area ◽  
Volume Effect ◽  
Membrane Curvature ◽  
Repulsive Interaction ◽  
Steric Interaction ◽  
Multilayer Systems ◽  
Fluid Membranes ◽  
Excluded Volume Effect ◽  
Out Of Plane ◽  
Curvature Elasticity

AbstractThe out-of-plane fluctuations of fluid membranes are sterically hindered in multilayer systems. The repulsive interaction associated with the steric or excluded-volume effect is studied theoretically by two methods. The interaction energy per unit area of membrane is derived as a function of temperature, membrane curvature elasticity and mean membrane spacing; it is inversely proportional to the square of the latter. Steric repulsion is estimated for lecithin bilayers in water. There and in other cases, it may compete with van der Waals attraction.

Kinetic Energy Budget for the Madden–Julian Oscillation in a Multiscale Framework

2012 ◽  
Vol 25 (15) ◽  
pp. 5386-5403 ◽  
Author(s):  
Lei Zhou ◽  
Adam H. Sobel ◽  
Raghu Murtugudde
Keyword(s):  
Kinetic Energy ◽  
Energy Budget ◽  
Small Scale ◽  
Gradient Force ◽  
Pressure Gradient Force ◽  
Madden Julian Oscillation ◽  
Upper Troposphere ◽  
Kinetic Energy Budget ◽  
Work Done ◽  
Multiscale Interaction

Abstract A kinetic energy budget for the Madden–Julian oscillation (MJO) is established in a three-scale framework. The three scales are the zonal mean, the MJO scale with wavenumbers 1–4, and the small scale with wavenumbers larger than 4. In the composite budget, the dominant balance at the MJO scale is between conversion from potential energy and work done by the pressure gradient force (PGF). This balance is consistent with the view that the MJO wind perturbations can be viewed as a quasi-linear response to a slowly varying heat source. A large residual in the upper troposphere suggests that much kinetic energy dissipates there by cumulus friction. Kinetic energy exchange between different scales is not a large component of the composite budget. There is a transfer of kinetic energy from the MJO scale to the small scale; that is, this multiscale interaction appears to damp rather than strengthen the MJO. There is some variation in the relative importance of different terms from one event to the next. In particular, conversion from mean kinetic energy can be important in some events. In a few other events, the influence from the extratropics is pronounced.

THE RELATION BETWEEN COIL AREA, TEMPERATURE OF COOLING MEDIUM AND DEHYDRATION IN A COLD STORAGE ROOM

1933 ◽  
Vol 8 (1) ◽  
pp. 475-487
Author(s):  
O. C. YOUNG
Keyword(s):  
Constant Temperature ◽  
Cold Storage ◽  
Temperature Difference ◽  
Room Temperature ◽  
Unit Area ◽  
Small Scale ◽  
Storage Room ◽  
Ordinary Type ◽  
Temperature Levels ◽  
Cooling Coil

In studies with a small scale cold storage room of ordinary type a relation was obtained between coil area and temperature of brine for a constant room temperature and given outside conditions. The dehydrating effect in the room was found to decrease as the cooling coil area was increased. As the evaporating area of stored material was increased the dehydration per unit area was found to decrease slightly, and at different temperature levels the dehydration for a constant temperature difference between inside and outside air was found to correspond closely to the capacity of air for holding moisture at the respective temperature levels.

Design and Testing of a Thin-Flexure Bistable Mechanism Suitable for Stamping From Metal Sheets

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Benjamin Todd ◽  
Brian D. Jensen ◽  
Stephen M. Schultz ◽  
Aaron R. Hawkins
Keyword(s):  
Compliant Mechanisms ◽  
Elliptic Integral ◽  
Plane Motion ◽  
Acceleration Threshold ◽  
Metal Sheets ◽  
Out Of Plane ◽  
A New Technique ◽  
Bistable Mechanism ◽  
Force Displacement ◽  
Design And Testing

We present a new technique for fabricating compliant mechanisms from stamped metal sheets. The concept works by providing thinned segments to allow rotation of flexural beams 90 deg about their long axis, effectively providing a flexure as wide as the sheet’s thickness. The method is demonstrated with the design and fabrication of a metal bistable mechanism for use as a threshold accelerometer. A new model based on elliptic integral solutions is presented for bistable mechanisms incorporating long, thin flexures. The resulting metal bistable mechanisms are tested for acceleration threshold sensing using a drop test and a vibration test. The mechanisms demonstrate very little variation due to stress relaxation or temperature effects. The force-displacement behavior of a mechanism is also measured. The mechanisms’ switching force is less than the designed value because of out-of-plane motion and dynamic effects.

scholarly journals PROBING ATOMIC LEVEL INTERACTIONS IN NI NANORODS AND AFM CANTILEVER USING ATOMIC FORCE MICROSCOPY BASED F–D SPECTROSCOPY

2017 ◽  
Author(s):  
Sudipta Dutta ◽  
Mahesh Kumar Singh ◽  
M. S. Bobji
Keyword(s):  
Atomic Force Microscopy ◽  
Magnetic Interaction ◽  
Interaction Force ◽  
Small Scale ◽  
Magnetic Composite ◽  
Force Microscopy ◽  
Atomic Force ◽  
Lift Height ◽  
Afm Cantilever ◽  
Force Displacement

Atomic force microscopy based force-displacement spectroscopy is used to quantify magnetic interaction force between sample and magnetic cantilever. AFM based F–D spectroscopy is used widely to understand various surface-surface interaction at small scale. Here we have studied the interaction between a magnetic nanocomposite and AFM cantilevers. Two different AFM cantilever with same stiffness but with and without magnetic coating is used to obtain F–D spectra in AFM. The composite used has magnetic Ni nanophase distributed uniformly in an Alumina matrix. Retrace curves obtained using both the cantilevers on magnetic composite and sapphire substrate are compared. It is found for magnetic sample cantilever comes out of contact after traveling 100 nm distance from the actual point of contact. We have also used MFM imaging at various lift height and found that beyond 100nm lift height magnetic contrast is lost for our composite sample, which further confirms our F–D observation.

scholarly journals Aeroelastic stability of idling wind turbines

2017 ◽  
Vol 2 (2) ◽  
pp. 415-437 ◽  
Author(s):  
Kai Wang ◽  
Vasilis A. Riziotis ◽  
Spyros G. Voutsinas
Keyword(s):  
Wind Turbine ◽  
Time Domain ◽  
Operation Mode ◽  
Nonlinear Effects ◽  
Eigenvalue Stability ◽  
Out Of Plane ◽  
Aeroelastic Simulations ◽  
The Time Domain ◽  
Work Done ◽  
Nonlinear Time Domain

Abstract. Wind turbine rotors in idling operation mode can experience high angles of attack within the post-stall region that are capable of triggering stall-induced vibrations. The aim of the present paper is to extend the existing knowledge on the dynamics and aerodynamics of an idling wind turbine and characterize its stability. Rotor stability in slow idling operation is assessed on the basis of nonlinear time domain and linear eigenvalue analyses. The aim is to establish when linear analysis is reliable and identify cases for which nonlinear effects are significant. Analysis is performed for a 10 MW conceptual wind turbine designed by DTU. First, the flow conditions that are likely to favor stall-induced instabilities are identified through nonlinear time domain aeroelastic simulations. Next, for the above specified conditions, eigenvalue stability analysis is performed to identify the low damped modes of the turbine. The eigenvalue stability results are evaluated through computations of the work done by the aerodynamic forces under imposed harmonic motion following the shape and frequency of the various modes. Nonlinear work characteristics predicted by the ONERA and Beddoes–Leishman (BL) dynamic stall models are compared. Both the eigenvalue and work analyses indicate that the asymmetric and symmetric out-of-plane modes have the lowest damping. The results of the eigenvalue analysis agree well with those of the nonlinear work analysis and the time domain simulations.

scholarly journals DISPLACEMENTS OF SIDE WALLS WITH WALL-GIRTS IN INDUSTRIAL BUILDINGS UNDER VERTICAL SETTLEMENTS

2021 ◽  
Vol 30 (1) ◽  
Author(s):  
Noemí M. Subelza ◽  
Verónica A. Pedrozo ◽  
Rossana C. Jaca ◽  
Luis A. Godoy
Keyword(s):  
Computer Modelling ◽  
Computational Modelling ◽  
Full Scale ◽  
Scale Model ◽  
Design Stage ◽  
Small Scale ◽  
Industrial Buildings ◽  
Out Of Plane ◽  
Side Walls ◽  
Lateral Displacements

The localized settlement of columns in large metal industrial buildings induces out-of-plane displacements of side walls of the same order as the settlement, which may affect service conditions in the building. For a structural configuration formed by frames, side-walls and wall-girts, this work reports results from testing a small-scale model together with computational modelling of the full-scale structure. Dimensional analysis was used to scale the geometry and properties from full-scale to small-scale, leading to an overall scale factor of 1:15. Differential settlements having a controlled amplitude were imposed at the central column, and displacements were monitored using mechanical devices. The computational model employed shell elements for side-walls and wall- girts. Good agreement was found between tests and computer modelling. The results at the full- scale level, indicate that, for settlements likely to occur in granular soils, the associated lateral displacements exceed those allowed by current US regulations. Stiffening the structure was investigated by use of stiffer girts, as well as by reducing their spacing. The influence of frame height was also investigated. The overall conclusion is that out-of-plane displacements of side- walls may easily exceed allowable values unless they are specifically considered at a design stage.

Sign in / Sign up

Export Citation Format

Share Document