Dynamic Response of Small Cantilever Beams in Viscous Media

2010 ◽  
Author(s):  
A. Mishty ◽  
P. Stewart ◽  
A. Mian
Keyword(s):  
Resonance Frequency ◽  
Resonance Peak ◽  
Laser Vibrometer ◽  
Cantilever Beams ◽  
Q Factor ◽  
Thin Steel ◽  
Viscous Media ◽  
Lubrication Oils ◽  
Steel Foils

We have considered two configurations of cantilever beam for characterization of rheological properties (density and viscosity) of viscous material. Both the beams are made of thin steel foils, having different free end condition. The beams were vibrated in various viscous fluids such as water and lubrication oils under sweeping modes, and the frequency response of the beam was measured using Polytec laser vibrometer. For both beam configurations, the resonance frequency decreased while the width of the resonance peak (related to Q-factor) increased with increasing viscosity and density. Thus, the viscosity and the density of a liquid can be determined simultaneously using the experimentally measured resonance frequency and peak width.

scholarly journals Experimental study and characterization of magnetoelastic ribbons as vibration sensors and their application for the identification of cracks in cantilever beams through the dynamic behavior of the beam

2020 ◽  
Author(s):  
Γεώργιος Σαμουργκανίδης
Keyword(s):  
Experimental Study ◽  
Dynamic Behavior ◽  
Cantilever Beam ◽  
Pattern Matching ◽  
Cantilever Beams ◽  
Q Factor ◽  
Proof Of Concept ◽  
Vibration Sensors ◽  
Matching Process

Στη παρούσα διατριβή λεπτές ταινίες μαγνητοελαστικού υλικού τύπου Metglas (άμορφο μεταλλικό κράμα Metglas 2826MB) μελετήθηκαν, χαρακτηρίσθηκαν και εφαρμόστηκαν ως αισθητήρας δονήσεων. Τέτοια υλικά έχουν την ιδιότητα να αλλάζουν την μαγνητική τους κατάσταση (μαγνήτιση) και να παράγουν μαγνητικά πεδία υπό την επίδραση μιας μηχανικής τάσης (Villary effect), και αντίστροφα να παραμορφώνονται μηχανικά όταν σε αυτά εφαρμοστεί κάποιο μαγνητικό πεδίο (magnetostriction). Στη παρούσα διατριβή, τα υλικά αυτά χρησιμοποιήθηκαν ως αισθητήρες δονήσεων με τη μορφή λεπτών ταινιών, και προσκολλήθηκαν πάνω στην επιφάνεια μιας μηχανικής δομής, όπως μία δοκός προβόλου (cantilever beam), για την παρακολούθηση της μηχανικής υγείας της δομής, παρουσία ρωγμών, μέσω των φυσικών της συχνοτήτων κάμψης. Το πειραματικό μέρος της διατριβής χωρίζεται σε τρεις βασικές φάσεις οι οποίες είναι, η επαλήθευση της χρήσης των υλικών αυτών ως αισθητήρες δονήσεων (proof of concept), ο πλήρης χαρακτηρισμός τους και τέλος η εφαρμογή τους στη ταυτοποίηση της μηχανικής υγείας της υπό μελέτης μηχανικής δομής. Στην παρούσα διατριβή, η σειρά των πειραμάτων ήταν σύμφωνη με την σειρά αυτών των φάσεων. Έτσι, όσον αφορά την πρώτη φάση, διερευνήθηκε η ικανότητα των μαγνητοελαστικών ταινιών να ανιχνεύουν και να μεταδίδουν την δονητική κατάσταση της μηχανικής δομής στην οποία ήταν επικολλημένες, καθώς και η ακρίβεια αυτών στην ανίχνευση της αλλαγής της δονητικής κατάστασης της δομής παρουσία ρωγμών, μέσω των καταγεγραμμένων δεδομένων των ιδιοσυχνοτήτων κάμψης. Για την εκτέλεση του έργου αυτού, ένα πλήθος διαφορετικών δειγμάτων προβόλου, άθικτων και μη, από κράμα αλουμινίου 6063 χρησιμοποιήθηκαν, και τα δεδομένα της ανίχνευσης των ιδιοσυχνοτήτων κάμψης συγκρίθηκαν με αντίστοιχα αριθμητικά αποτελέσματα από φασματικές προσομοιώσεις στο πρόγραμμα ANSYS. Κατά την δεύτερη φάση πραγματοποιήθηκε το πείραμα χαρακτηρισμού των ταινιών αυτών ως αισθητήρες δόνησης και μελετήθηκαν συνολικά επτά διαφορετικοί παράμετροι αισθητήρων όπως είναι η συχνοτική απόκριση, η γραμμικότητα, ο λόγος σήματος προς θόρυβο (SNR), ο συντελεστής ποιότητας (Q factor), η σταθερότητα, η επαναληψιμότητα και η ευαισθησία. Το πείραμα αυτό του χαρακτηρισμού πραγματοποιήθηκε με την χρήση δύο διαφορετικών πειραματικών διατάξεων, μία για την εξέταση της παραμέτρου της συχνοτικής απόκρισης και μία για την εξέταση των υπολοίπων παραμέτρων. Η τρίτη και τελευταία φάση περιλαμβάνει την εφαρμογή των υπό εξέταση αισθητήρων δόνησης για τον εντοπισμό και την ταυτοποίηση ρωγμών σε μηχανικές δομές, όπως η δοκός πρόβολος, μέσω μια προτεινόμενης μεθοδολογίας αναγνώρισης ρωγμών. Η μεθοδολογία περιλαμβάνει της χρήση μιας διεργασίας αντιστοίχισης προτύπων (pattern matching process), μέσω μιας διαδικασίας ελαχιστοποίησης της διασποράς των πειραματικών και θεωρητικών δεδομένων, προκειμένου να ταυτοποιηθεί η θέση και το βάθος της ρωγμής, και να προσδιοριστεί η μηχανική κατάσταση-υγεία της δομής. Οι μέθοδοι εκτέλεσης των πειραμάτων και τα πειραματικά δεδομένα της κάθε φάσης εξετάστηκαν λεπτομερώς και διεξοδικά, με τα αποτελέσματα αυτών να παρουσιάζονται και να περιγράφονται αναλυτικά στο κείμενο της διατριβής.

scholarly journals Pyrolytic carbon resonators for micromechanical thermal analysis

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Long Quang Nguyen ◽  
Peter Emil Larsen ◽  
Tom Larsen ◽  
Sanjukta Bose Goswami ◽  
Luis Guillermo Villanueva ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Electrical Conductivity ◽  
Resonance Frequency ◽  
Quality Factor ◽  
Pyrolytic Carbon ◽  
Q Factor ◽  
Scanning Calorimetry ◽  
Quality Factor Q ◽  
Poly Caprolactone

Abstract Thermal analysis is essential for the characterization of polymers and drugs. However, the currently established methods require a large amount of sample. Here, we present pyrolytic carbon resonators as promising tools for micromechanical thermal analysis (MTA) of nanograms of polymers. Doubly clamped pre-stressed beams with a resonance frequency of 233 ± 4 kHz and a quality factor (Q factor) of 800 ± 200 were fabricated. Optimization of the electrical conductivity of the pyrolytic carbon allowed us to explore resistive heating for integrated temperature control. MTA was achieved by monitoring the resonance frequency and quality factor of the carbon resonators with and without a deposited sample as a function of temperature. To prove the potential of pyrolytic carbon resonators as thermal analysis tools, the glass transition temperature (Tg) of semicrystalline poly(L-lactic acid) (PLLA) and the melting temperature (Tm) of poly(caprolactone) (PCL) were determined. The results show that the Tg of PLLA and Tm of PCL are 61.0 ± 0.8 °C and 60.0 ± 1.0 °C, respectively, which are in excellent agreement with the values measured by differential scanning calorimetry (DSC).

scholarly journals Synthesis and Piezoelectric Characterization of UV-Curable Nanocellulose/ZnO/AlN Polymeric Flexible Films for Green Energy Generation Applications

Proceedings ◽  
2020 ◽  
Vol 56 (1) ◽  
pp. 36
Author(s):  
Maria Assunta Signore ◽  
Giulio Malucelli ◽  
Donatella Duraccio ◽  
Chiara De Pascali ◽  
Ambra Fioravanti ◽  
...  
Keyword(s):  
Energy Generation ◽  
Green Energy ◽  
Nitride Film ◽  
Cantilever Beams ◽  
Functional Coatings ◽  
Uv Curable ◽  
Mass Insertion ◽  
Flexible Films ◽  
Piezoelectric Behavior

In this work, the fabrication of composites consisting of piezoelectric ZnO ceramic nanostructures and nanocellulose fillers in a UV-cured acrylic matrix has been exploited for the design of new functional coatings for green energy generation. The piezoelectric behavior was investigated at different accelerations applied to cantilever beams. The piezoelectric signal generated by the different ZnO nanostructures was improved by aluminum nitride film integration on the beam and proof mass insertion at the tip.

Amorphous Silicon TFTs on Steel-Foil Substrates

1996 ◽  
Vol 424 ◽  
Author(s):  
S. D. Theiss ◽  
S. Wagner
Keyword(s):  
Stainless Steel ◽  
Leakage Currents ◽  
Action Current ◽  
Insulating Layer ◽  
Stainless Steel Foil ◽  
Current Voltage ◽  
Stainless Steel Foils ◽  
Steel Foils ◽  
Current Behavior

AbstractWe describe the successful fabrication of device-quality a-Si:H thin-film transistors (TFTs) on stainless-steel foil substrates. These TFTs demonstrate that transistor circuits can be made on a flexible, non-breakable substrate. Such circuits could be used in reflective or emissive displays, and in other applications that require rugged macroelectronic circuits.Two inverted TFT structures have been made, using 200 gim thick stainless steel foils with polished surfaces. In the first structure we used the substrate as the gate and utilized a homemade mask set with very large feature sizes: L = 45 μm; W = 2.5 mm. The second, inverted staggered, structure used a 9500 Å a-SiNx:H passivating/insulating layer deposited on the steel to enable the use of isolated gates. For this structure we used a mask set which is composed of TFTs with much smaller feature sizes. Both TFT structures exhibit transistor action. Current-voltage characterization of the TFTs with the inverted staggered structure shows typical on/off current ratios of 107, leakage currents on the order of 10-12 A, good linear and saturation current behavior, and channel mobilities of 0.5 cm2/V·sec. These characteristics clearly identify the TFTs grown on stainless steel foil as being of device quality.

Qualitative and Quantitative Characterization of Airport-related Ultrafine Particles using Liquid Chromatography – High-Resolution Mass Spectrometry (UHPLC/HRMS)

2021 ◽  
Author(s):  
Florian Ungeheuer ◽  
Diana Rose ◽  
Dominik van Pinxteren ◽  
Florian Ditas ◽  
Stefan Jacobi ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Ultrafine Particles ◽  
Chemical Characterization ◽  
Engine Oil ◽  
Aircraft Emissions ◽  
Jet Engine ◽  
Qualitative And Quantitative ◽  
Ionization Mode ◽  
Lubrication Oils

<p>We present the results from a chemical characterization study of ultrafine particles (UFP), collected nearby Frankfurt International Airport where particle size distribution measurements showed high number concentrations for particles with a diameter <50 nm. Aluminium filter samples were collected at an air quality monitoring station in a distance of 4 km to Frankfurt airport, using the 13-stage cascade impactor Nano-MOUDI (MSP Model-115). The chemical characterization of the ultrafine particles in the size range of 0.010-0.018 μm, 0.018-0.032 μm and 0.032-0.056 μm was accomplished by the development of an optimized filter extraction method. An UHPLC method for chromatographic separation of homologous series of hydrophobic and high molecular weight organic compounds, followed by heated electrospray ionization (ESI) and mass analysis using an Orbitrap high-resolution mass spectrometer was developed. Using a non-target screening, ~200 compounds were detected in the positive ionization mode after filtering, in order to ensure high quality of the obtained data. We determined the molecular formula of positively charged adducts ([M+H]<sup>+</sup>; [M+Na]<sup>+</sup>), and for each impaction stage we present molecular fingerprints (Molecular weight vs Retention time, Kroll-diagram, Van-Krevelen-diagram, Kendrick mass defect plot) in order to visualize the complex chemical composition. The negative ionization mode led only to the detection of a few compounds (<20) for which reason the particle characterization focuses on the positive ionization mode. We found that the majority of detected compounds belong to homologous series of two different kinds of organic esters, which are base stocks of aircraft lubrication oils. In reference to five different jet engine lubrication oils of various manufacturers, we identified the corresponding lubricant base stocks and their additives in the ultrafine particles by the use of matching retention time, exact mass and MS/MS fragmentation pattern of single organic molecules. As the relevance of the chemical composition of UFP regarding human health is depending on the mass contribution of each compound we strived for quantification of the jet engine oil compounds. This was achieved by standard addition of purchased original standards to the native sample extracts. Two amines serving as stabilizers, one organophosphate used as an anti-wear agent/metal deactivator and two ester base stocks were quantified. Quantification of the two homologous ester series was carried out using one ester compound and cross-calibration. The quantitative determination is burdened by the uncertainty regarding sampling artefacts in the Nano-MOUDI. Therefore we characterized the cascade impactor in a lab experiment using the ester standard. Particle size distribution measurements conducted parallel to the filter sampling enables the determination of jet engine oil contribution to the UFP mass. Results indicate that aircraft emissions strongly influence the mass balance of 0.010-0.018 μm particles. This contribution decreases for bigger sized particles (0.018-0.056 μm) as presumably more sources get involved. The hereby-introduced method allows the qualitative and quantitative assignment of aircraft emissions towards the chemical composition and total mass of airport related ultrafine particles.</p>

scholarly journals Electromechanical Characterization and Locomotion Control of IPMC BioMicroRobot

2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Martin J.-D. Otis
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Water Electrolysis ◽  
Laser Vibrometer ◽  
Metal Composite ◽  
Current Consumption ◽  
Polymer Metal ◽  
Multiple Frequencies ◽  
Electromechanical Characterization

This paper presents the electromechanical characterization of Nafion-Pt microlegs for the development of an insect-like hexapod BioMicroRobot (BMR). BMR microlegs are built using quasi-cylindrical Nafion-Pt ionomeric polymer-metal composite (IPMC), which has 2.5 degrees of freedom. The specific manufacturing process using a laser excimer for one leg in three-dimensional configurations is discussed. Dynamic behavior and microleg characteristics have been measured in deionized water using a laser vibrometer. The use of the laser vibrometer shows the linear characteristics between the duty cycle of square wave input and displacement rate of the actuator at multiple frequencies. This linearity is used to design a servo-system in order to reproduce insect tripod walking. As well, BMR current consumption is an important parameter evaluated for each leg. Current passing throughout the IPMC membrane can result in water electrolysis. Four methods are explained for avoiding electrolysis. The hardware test bench for measurements is presented. The purpose of this design is to control a BMR for biomedical goals such as implantation into a human body. Experimental results for the proposed propulsion system are conclusive for this type of bioinspired BMR.

Design and Characterization of Single Beam for Latching Electrothermal Microswitch

2012 ◽  
Vol 468-471 ◽  
pp. 286-289
Author(s):  
Ying Zhang ◽  
Hong Wang ◽  
Yan Wang ◽  
Sheng Ping Mao ◽  
Gui Fu Ding
Keyword(s):  
Mechanical Performance ◽  
Stable State ◽  
Cantilever Beams ◽  
Analysis Software ◽  
Stable States ◽  
Element Analysis ◽  
Single Beam ◽  
Fabrication And Characterization ◽  
Continuous Power

This paper presents the design, fabrication and characterization of single beam for latching electrothermal microswitch. This microswitch consists of two cantilever beams using bimorph electrothermal actuator with mechanical latching for performing low power bistable relay applications. A stable state can be acquired without continuous power which is only needed to switch between two stable states of the microactuator. The single beam is discussed mainly to judge the possibility of realizing the designed function. First, reasonable shape of the resistance is designed using finite element analysis software ANSYS. Then, mechanical performance was characterized by WYKO NT1100 optical profiling system, the tip deflection of single beam can meet the designed demand.

Free-Space Scattering Characterization of Ultrathin Reflective Metasurfaces and High-Q-Factor Sensing Methods for Conductor-Backed Materials

2021 ◽  
Author(s):  
Feng-Yuan Han ◽  
Jin Zhao ◽  
Zi-Wen Zhang ◽  
Ming-Zhe Chong ◽  
Li-Zheng Yin ◽  
...  
Keyword(s):  
Free Space ◽  
Q Factor ◽  
High Q

scholarly journals A Geometrical Study on the Roof Tile-Shaped Modes in AlN-Based Piezoelectric Microcantilevers as Viscosity–Density Sensors

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 658 ◽  
Author(s):  
Víctor Ruiz-Díez ◽  
Javier Toledo ◽  
Jorge Hernando-García ◽  
Abdallah Ababneh ◽  
Helmut Seidel ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Quality Factor ◽  
Q Factor ◽  
Liquid Media ◽  
Roof Tile ◽  
Aln Film ◽  
Monitoring Applications ◽  
Media Monitoring ◽  
Comprehensive Study

Cantilever resonators based on the roof tile-shaped modes have recently demonstrated their suitability for liquid media monitoring applications. The early studies have shown that certain combinations of dimensions and order of the mode can maximize the Q-factor, what might suggest a competition between two mechanisms of losses with different geometrical dependence. To provide more insight, a comprehensive study of the Q-factor and the resonant frequency of these modes in microcantilever resonators with lengths and widths between 250 and 3000 µm and thicknesses between 10 and 60 µm is presented. These modes can be efficiently excited by a thin piezoelectric AlN film and a properly designed top electrode layout. The electrical and optical characterization of the resonators are performed in liquid media and then their performance is evaluated in terms of quality factor and resonant frequency. A quality factor as high as 140 was measured in isopropanol for a 1000 × 900 × 10 µm3 cantilever oscillating in the 11th order roof tile-shaped mode at 4 MHz; density and viscosity resolutions of 10−6 g/mL and 10−4 mPa·s, respectively are estimated for a geometrically optimized cantilever resonating below 1 MHz.

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