scholarly journals Fabrications of L-Band LiNbO3-Based SAW Resonators for Aerospace Applications

Micromachines ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 349 ◽  
Author(s):  
Baofa Hu ◽  
Shaoda Zhang ◽  
Hong Zhang ◽  
Wenlong Lv ◽  
Chunquan Zhang ◽  
...  
Keyword(s):  
Electron Beam ◽  
Design Parameters ◽  
Strain Sensing ◽  
Aerospace Applications ◽  
Fem Method ◽  
Submicron Scale ◽  
L Band ◽  
Band Saw ◽  
Quality Factor Q ◽  
Saw Resonators

High frequency surface acoustic wave (SAW) technology offers many opportunities for aerospace applications in passive wireless sensing and communication. This paper presents the design, simulation, fabrication, and test of an L-band SAW resonator based on 128° Y-X LiNbO3 substrate. The design parameters of SAW resonator were optimized by the finite element (FEM) method and the coupling-of-mode (COM) theory. Electron-beam lithography (EBL) technology was used to fabricate the submicron-scale of interdigital transducers (IDTs) and grating reflectors. The effects of some key EBL processes (e.g., the use of electron beam resist, the choice of metal deposition methods, the charge-accumulation effect, and the proximity-effect) on the fabrication precision of SAW devices were discussed. Experimentally, the LiNbO3-based SAW resonators fabricated using improved EBL technology exhibits a Rayleigh wave resonance peaks at 1.55 GHz with return loss about −12 dB, and quality factor Q is 517. Based on this SAW resonator, the temperature and strain sensing tests were performed, respectively. The experimental results exhibit a well linear dependence of temperature/strain on frequency-shift, with a temperature sensitivity of 125.4 kHz/°C and a strain sensitivity of −831 Hz/με, respectively.

Correlation Between Microstructure and Mechanical Properties in an Inconel 718 Deposit Produced Via Electron Beam Freeform Fabrication

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Wesley A. Tayon ◽  
Ravi N. Shenoy ◽  
MacKenzie R. Redding ◽  
R. Keith Bird ◽  
Robert A. Hafley
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Crystallographic Texture ◽  
Inconel 718 ◽  
Electron Backscatter Diffraction ◽  
Microstructural Characterization ◽  
Freeform Fabrication ◽  
Aerospace Applications ◽  
Evolution Of Microstructure ◽  
Texture Characterization

Electron beam freeform fabrication (EBF3), a metallic layer-additive manufacturing process, uses a high-power electron beam in conjunction with a metal feed wire to create a molten pool on a substrate, which on solidification produces a component of the desired configuration made of sequentially deposited layers. During the build-up of each solidified layer, the substrate is translated with respect to the electron beam and the feed wire. EBF3 products are similar to conventional cast products with regard to the as-deposited (AD) microstructure and typical mechanical properties. Inconel 718 (IN 718), a high-temperature superalloy with attractive mechanical and oxidation properties well suited for aerospace applications, is typically used in the wrought form. The present study examines the evolution of microstructure, crystallographic texture, and mechanical properties of a block of IN 718 fabricated via the EBF3 process. Specimens extracted out of this block, both in the AD and in a subsequently heat treated (HT) condition, were subjected to (1) microstructural characterization using scanning electron microscopy (SEM); (2) in-plane elastic modulus, tensile strength, and microhardness evaluations; and (3) crystallographic texture characterization using electron backscatter diffraction (EBSD). Salient conclusions stemming from this study are: (1) mechanical properties of the EBF3-processed IN 718 block are strongly affected by texture as evidenced by their dependence on orientation relative to the EBF3 fabrication direction, with the AD EBF3 properties generally being significantly reduced compared to wrought IN 718; (2) significant improvement in both strength and modulus of the EBF3 product to levels nearly equal to those for wrought IN 718 may be achieved through heat treatment.

Influence of Planetary Needle Bearings on the Performance of Single and Double Pinion Planetary Systems

2006 ◽  
Vol 129 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Avinash Singh
Keyword(s):  
High Stress ◽  
System Level ◽  
Design Parameters ◽  
Major Influence ◽  
Contact Pattern ◽  
Analysis Model ◽  
Planetary Gears ◽  
Aerospace Applications ◽  
Bending Stresses ◽  
Bearing Loads

Planetary gears are widely used in automotive and aerospace applications. Due to demands for greater power density, these gearsets often operate at extremely high stress levels. This has caused system level influences once considered secondary to become critical to the success of planetary gears. One such system level effect that has been largely overlooked is the influence of support structures like planetary needle bearings. There are interactions between the gear distributed loads and the resulting bearing loads and deflections that have implications for both gear and bearing designs. Also, double pinion planetary arrangements are increasingly becoming common. There are still greater interactions between the gear and bearing components in double pinion planetary arrangements. In this paper, we will examine the influence of the bearing deflections (tilt) on the gear load distribution and contact pattern. We will also show the influence of distributed gear loads on the bearing loads (moments) and deflections (tilts). Both, single and double pinion planetary arrangements will be considered. It will be shown that the tilting stiffnesses of the needle bearings have a major influence on gear contact pattern and consequently on contact and bending stresses. It will also be shown that the double pinion planetary arrangement is more likely to result in off-centered loading. Parametric studies will be performed to show the influence of a few design parameters. Theoretical derivations will be validated by numerical simulations. A system level gear analysis model will be used to illustrate the issues involved and quantify the results.

Mechanism and Bias Considerations for Design of a Bi-Directional Artificial Muscle Actuator

2012 ◽  
Author(s):  
Robert D. Vocke ◽  
Curt S. Kothera ◽  
Norman M. Wereley
Keyword(s):  
Artificial Muscle ◽  
Design Parameters ◽  
Artificial Muscles ◽  
Baseline Design ◽  
Aerospace Applications ◽  
Arbitrary Loading ◽  
Mckibben Actuators ◽  
Improved Design ◽  
Kinematic Mechanism ◽  
Selection Of

Pneumatic artificial muscles (PAMs), or McKibben actuators, have received considerable attention for robotic manipulators and in aerospace applications due to their similarity to natural muscles. Like natural muscles, PAMs are a purely contractile actuator, so that, in order to produce bidirectional or rotational motion, they must be arranged in an agonist/antagonist pair, which inherently limits the deflection of the system due to the high parasitic stiffness of the antagonistic PAM. This study presents two methods for increasing the performance of an antagonistic PAM system by decreasing the passive parasitic moment, rather than increasing the active moment. The first involves selection of the kinematic mechanism geometry, and the second involves the introduction of bias into the system, both in terms of PAM contraction, and passive (antagonistic) PAM pressure. It was found with the proper selection of design parameters, including mechanism geometry, PAM geometry, and bias conditions, that an ideal actuator configuration can be found that maximizes deflection for a given arbitrary loading. When comparing a baseline design to an improved design for a simplified case, a nearly 50% increase in maximum deflection was predicted simply by optimizing mechanism geometry and bias contraction.

scholarly journals Electron beam fabrication of a microfluidic device for studying submicron-scale bacteria

2013 ◽  
Vol 11 (1) ◽  
pp. 12 ◽  
Author(s):  
M Moolman ◽  
Zhuangxiong Huang ◽  
Sriram Krishnan ◽  
Jacob WJ Kerssemakers ◽  
Nynke H Dekker
Keyword(s):  
Electron Beam ◽  
Microfluidic Device ◽  
Submicron Scale

Electron Beam Misalignment Study of MIG for 42 GHz, 200 kW Gyrotron

Frequenz ◽  
2017 ◽  
Vol 71 (11-12) ◽  
Author(s):  
S. K Sharma ◽  
Udaybir Singh ◽  
Nitin Kumar ◽  
Naveen Sahu ◽  
Narendra Shekhawat ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Axial Velocity ◽  
Transverse Velocity ◽  
Velocity Ratio ◽  
Velocity Spread ◽  
Design Parameters ◽  
Simulation Results

AbstractThis paper presents the electron beam misalignment study with respect to cathode position and cathode magnetic field of 42 GHz, 200 kW gyrotron. The performance of gyrotron is affected with the misalignment of cathode position. The simulation results confirm the tolerance of cathode misalignment with respect to the design parameters such as the transverse-to-axial velocity ratio, the maximum transverse velocity spread, etc.

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