Piezoelectric T-Beam Microactuators

2008 ◽  
Author(s):  
Hareesh K. R. Kommepalli ◽  
Andrew D. Hirsh ◽  
Christopher D. Rahn ◽  
Srinivas A. Tadigadapa
Keyword(s):  
Cross Section ◽  
Fabrication Process ◽  
Mems Fabrication ◽  
Out Of Plane ◽  
Cantilevered Beam ◽  
Piezoelectric Mems ◽  
The Cross ◽  
T Beam ◽  
Cross Section Geometry

This paper introduces a novel T-beam actuator fabricated by a piezoelectric MEMS fabrication process. ICP-RIE etching from the front and back of a bulk PZT chip is used to produce stair stepped structures through the thickness with complex inplane shapes. Masked electrode deposition creates active and passive regions in the PZT structure. With a T-shaped crosssection, and bottom and top flange and web electrodes, a cantilevered beam can bend in-plane and out-of-plane with bimorph actuation in both directions. One of these T-beam actuators is fabricated and experimentally tested. An experimentally validated model predicts that the cross-section geometry can be optimized to produce higher displacement and blocking force.

Displacement and Blocking Force Performance of Piezoelectric T-Beam Actuators

2010 ◽  
Author(s):  
Hareesh K. R. Kommepalli ◽  
Kiron Mateti ◽  
Christopher D. Rahn ◽  
Srinivas A. Tadigadapa
Keyword(s):  
Theoretical Prediction ◽  
Cross Section ◽  
Experimental Validation ◽  
Analytical Models ◽  
Out Of Plane ◽  
Cantilevered Beam ◽  
Beam Displacement ◽  
T Beam ◽  
Meso Scale ◽  
Shaped Cross Section

In this paper, we present the experimental validation of the detailed models developed for the flexural motion of piezoelectric T-beam actuators. With a T-shaped cross-section, and bottom and top flange and web electrodes, a cantilevered beam can bend in both in-plane and out-of-plane directions upon actuation. Analytical models predict the tip displacement and blocking force in both directions. Mechanical dicing and flange electrode deposition was used to fabricate six meso-scale T-beam prototypes. The T-beams were experimentally tested for in-plane and out-of-plane displacements, and out-of-plane blocking force. The analytical models closely predict the T-beam displacement and blocking force performance. A nondimensional analytical model predict that all T-beam designs for both in-plane and out-of-plane actuation, regardless of scale, have nondimensional displacement and blocking force equal to nondimensional voltage. The results from experiments are favorably compared with this theoretical prediction.

Piezoelectric T-Beam Actuators

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Hareesh K. R. Kommepalli ◽  
Kiron Mateti ◽  
Christopher D. Rahn ◽  
Srinivas A. Tadigadapa
Keyword(s):  
Cross Section ◽  
Performance Optimization ◽  
Mechanical Energy ◽  
Analytical Models ◽  
Width Ratio ◽  
Maximum Displacement ◽  
Out Of Plane ◽  
Cantilevered Beam ◽  
Beam Displacement ◽  
T Beam

This paper develops models, fabricates, experimentally tests, and optimizes a novel piezoelectric T-beam actuator. With a T-shaped cross-section, and bottom and top flanges and web electrodes, a cantilevered beam can bend in both in-plane and out-of-plane directions upon actuation. Analytical models predict the tip displacement and blocking force in both directions. Six mesoscale T-beam prototypes are monolithically fabricated by machining and microfabrication techniques and experimentally tested for in-plane and out-of-plane displacements and out-of-plane blocking force. The analytical models closely predict the T-beam displacement and blocking force performance. A nondimensional analytical model predicts that all T-beam designs for both in-plane and out-of-plane actuations, regardless of scale, have nondimensional displacement and blocking force equal to nondimensional voltage. Another form of nondimensional model optimizes the T-beam cross-section for maximum performance. Optimization study shows that a cross-section with width ratio, b*, and thickness ratio, t*, approaching zero produces maximum displacement, b*=t*=0.381 produces maximum blocking force, and b*≈0.25, t*≈0.33 produces maximum mechanical energy.

Design variation of thin-walled composite beam cross-section properties

2016 ◽  
Vol 12 (3) ◽  
pp. 558-576 ◽  
Author(s):  
Aníbal J.J. Valido ◽  
João Barradas Cardoso
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Laminated Composite ◽  
Adjoint System ◽  
Design Sensitivity ◽  
Content Type ◽  
Design Elements ◽  
Thin Walled ◽  
The Cross ◽  
Cross Section Geometry

Purpose The purpose of this paper is to present a design sensitivity analysis continuum formulation for the cross-section properties of thin-walled laminated composite beams. These properties are expressed as integrals based on the cross-section geometry, on the warping functions for torsion, on shear bending and shear warping, and on the individual stiffness of the laminates constituting the cross-section. Design/methodology/approach In order to determine its properties, the cross-section geometry is modeled by quadratic isoparametric finite elements. For design sensitivity calculations, the cross-section is modeled throughout design elements to which the element sensitivity equations correspond. Geometrically, the design elements may coincide with the laminates that constitute the cross-section. Findings The developed formulation is based on the concept of adjoint system, which suffers a specific adjoint warping for each of the properties depending on warping. The lamina orientation and the laminate thickness are selected as design variables. Originality/value The developed formulation can be applied in a unified way to open, closed or hybrid cross-sections.

scholarly journals Testing the effects of topography, geometry, and kinematics on modeled thermochronometer cooling ages in the eastern Bhutan Himalaya

Solid Earth ◽  
2018 ◽  
Vol 9 (3) ◽  
pp. 599-627 ◽  
Author(s):  
Michelle E. Gilmore ◽  
Nadine McQuarrie ◽  
Paul R. Eizenhöfer ◽  
Todd A. Ehlers
Keyword(s):  
Cross Section ◽  
Heat Production ◽  
Main Central Thrust ◽  
Radiogenic Heat ◽  
Radiogenic Heat Production ◽  
The Cross ◽  
Viable Approach ◽  
Topographic Evolution ◽  
Cross Section Geometry ◽  
Geometry And Kinematics

Abstract. In this study, reconstructions of a balanced geologic cross section in the Himalayan fold–thrust belt of eastern Bhutan are used in flexural–kinematic and thermokinematic models to understand the sensitivity of predicted cooling ages to changes in fault kinematics, geometry, topography, and radiogenic heat production. The kinematics for each scenario are created by sequentially deforming the cross section with  ∼ 10 km deformation steps while applying flexural loading and erosional unloading at each step to develop a high-resolution evolution of deformation, erosion, and burial over time. By assigning ages to each increment of displacement, we create a suite of modeled scenarios that are input into a 2-D thermokinematic model to predict cooling ages. Comparison of model-predicted cooling ages to published thermochronometer data reveals that cooling ages are most sensitive to (1) the location and size of fault ramps, (2) the variable shortening rates between 68 and 6.4 mm yr−1, and (3) the timing and magnitude of out-of-sequence faulting. The predicted ages are less sensitive to (4) radiogenic heat production and (5) estimates of topographic evolution. We used the observed misfit of predicted to measured cooling ages to revise the cross section geometry and separate one large ramp previously proposed for the modern décollement into two smaller ramps. The revised geometry results in an improved fit to observed ages, particularly young AFT ages (2–6 Ma) located north of the Main Central Thrust. This study presents a successful approach for using thermochronometer data to test the viability of a proposed cross section geometry and kinematics and describes a viable approach to estimating the first-order topographic evolution of a compressional orogen.

Casting of Thin Bare Wire Using Wheel Caster Equipped with Rotating Side-Dam Plates

2020 ◽  
Vol 846 ◽  
pp. 152-156
Author(s):  
Toshio Haga ◽  
Kirito Itou ◽  
Hisaki Watari ◽  
Shinichi Nishida
Keyword(s):  
Aluminum Alloy ◽  
Mild Steel ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Side Surface ◽  
Fabrication Process ◽  
The Cross

A simple twin-wheel caster is proposed for casting thin bare wire. An unequal diameter twin wheel caster equipped with rotating side-dam plates is proposed for casting a thin bare wire of aluminum alloy to shorten the fabrication process. The rotating side-dam plate was made of mild steel. Al-10%Mg bare wire with a rectangular cross section could be cast at wheel speeds of 3 and 4 m/min. Area of the bare wire was less than 100 mm2 at these wheel speeds. The side surface of the bare wire was made flat by the rotating side-dam plates. The rotating side-dam plates prevent the cross section of the bare wire from becoming concave.

Convective Heat Transfer in Elliptical Microchannels Under Slip Flow Regime and H1 Boundary Conditions

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
Pamela Vocale ◽  
Gian Luca Morini ◽  
Marco Spiga
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Aspect Ratio ◽  
Boundary Conditions ◽  
Convective Heat Transfer ◽  
Cross Section ◽  
Convective Heat ◽  
Slip Flow ◽  
The Cross ◽  
Cross Section Geometry

In this work, hydrodynamically and thermally fully developed gas flow through elliptical microchannels is numerically investigated. The Navier–Stokes and energy equations are solved by considering the first-order slip flow boundary conditions and by assuming that the wall heat flux is uniform in the axial direction, and the wall temperature is uniform in the peripheral direction (i.e., H1 boundary conditions). To take into account the microfabrication of the elliptical microchannels, different heated perimeter lengths are analyzed along the microchannel wetted perimeter. The influence of the cross section geometry on the convective heat transfer coefficient is also investigated by considering the most common values of the elliptic aspect ratio, from a practical point of view. The numerical results put in evidence that the Nusselt number is a decreasing function of the Knudsen number for all the considered configurations. On the contrary, the role of the cross section geometry in the convective heat transfer depends on the thermal boundary condition and on the rarefaction degree. With the aim to provide a useful tool for the designer, a correlation that allows evaluating the Nusselt number for any value of aspect ratio and for different working gases is proposed.

Role of the Cross Section Geometry in Rectangular ${\rm Nb}_{3}{\rm Sn}$ CICC Performances

2011 ◽  
Vol 21 (3) ◽  
pp. 2032-2035 ◽  
Author(s):  
Simonetta Turtu ◽  
Luigi Muzzi ◽  
Chiarasole Fiamozzi Zignani ◽  
Valentina Corato ◽  
Antonio della Corte ◽  
...  
Keyword(s):  
Cross Section ◽  
The Cross ◽  
Cross Section Geometry

Out-of-Plane Impact at the Tip of a Right-Angled Bent Cantilever Beam

1995 ◽  
Vol 62 (4) ◽  
pp. 887-892 ◽  
Author(s):  
B. Wang ◽  
T. X. Yu ◽  
S. R. Reid
Keyword(s):  
Cantilever Beam ◽  
Cross Section ◽  
Bending Moment ◽  
Pure Bending ◽  
Concentrated Mass ◽  
Impulsive Load ◽  
Out Of Plane ◽  
History Of ◽  
The Cross

The present paper provides an analysis of the response of a right-angled bent cantilever beam subjected to an out-of-plane impulsive load (i.e., suddenly imposed velocity) applied to concentrated mass at its tip. If T0 and M0 are the fully plastic torque and bending moment, respectively, of the cross section, it is shown that for the case T0/M0 < 1, a double hinge mechanism is required, with a pure bending hinge in the first segment of the beam and a combined bending-torsion hinge in the second segment. The history of deformation is described following impartation of the load.

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