Quantification of Bolt Tension by Surface Acoustic Waves: An Experimentally Verified Simulation Study

Quantifying bolt tension and ensuring that bolts are appropriately tightened for large-scale civil infrastructures are crucial. This study investigated the feasibility of employing the surface acoustic wave (SAW) for quantifying the bolt tension via finite element modeling. The central hypothesis is that the real area of contact in a bolted joint increases as the tension or preload is increased, causing an acoustical signature change. The experimentally verified 3-D simulations were carried out in two steps: A preload was first applied to the bolt body to simulate the realistic behavior of bolted joint; and the SAW propagation was then excited on the top surface of the plate to reflect from the bolted joint. The bolt tension value was varied between 4 and 24 kN (properly tightened bolt) in the steps of 4 kN to study the effect of the bolt tension. The results indicate an increased reflected wave amplitude and a gradual phase shift, up to 0.5 µs, as the bolt tension increased. Furthermore, the result shows that the distance between the first reflected wave and the source becomes shorter as the preload increases, as hypothesized. A 1.9 mm difference in the distance between the maximum and minimum preload was observed. As part of this study, the simulation results were also compared with the experimental results, and a good agreement between the simulation and experiments was demonstrated.

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Determination of Adhesion Forces Between Smooth and Structured Solids

ASME/STLE 2012 International Joint Tribology Conference ◽

10.1115/ijtc2012-61132 ◽

2012 ◽

Author(s):

Hartmut R. Fischer ◽

Edwin R. M. Gelinck

Keyword(s):

Adhesion Force ◽

Smooth Surfaces ◽

Adhesion Forces ◽

Real Area Of Contact ◽

Study Results ◽

Colloidal Probes ◽

Good Agreement ◽

Real Area

The tendency of smooth surfaces to stick spontaneously to each other is becoming a serious problem, with: a) the increasing quality in surface finish for many components and systems, b) on miniaturization in mechanical components, and c) in demanded precision of positioning of parts in high-end equipment machines and systems. Surfaces tend to be made smoother in order to gain flatness or in order to fulfill the need for more precise and reproducible positioning of parts. Adhesion or even sticking of the surfaces is a major showstopper for these applications. There are several measures that can be taken in order to reduce spontaneous adhesion. Quantification of the effectiveness of the chosen solution is most often done using an AFM with probes varying from 1 nm to 8 micron of contact diameter. A serious disadvantage in measuring adhesion by sharp tips is the wear of the tips. Sharp tips wear easily, resulting in undefined contact areas. When the real area of contact is not well defined, the quantification of the adhesion force is not significant. In the current study results of AFM measurements from literature with different tip diameters of colloidal probes are compared with measurements we performed using AFM cantilevers with a plateau tip and using probes from large spheres using an alternative setup (UNAT). These methods give results that are in good agreement with values found in literature. Large contacting surface enhance the quality of the measured adhesion values. Another part of the study deals with a deliberately roughening of smooth surfaces to minimize (spontaneous) adhesion. Good agreement has been found with existing results. For the use of larger surfaces it is important that the surfaces to be tested are extremely clean. Particles on smooth surface do influence the measurements quite easily. Especially for larger areas, the possibility of encountering particles on the surface are more likely, when particles are present. For the measurements in this study a lot of care has been taken therefore to remove contamination: particles as well as contamination of organic origin.

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Friction of diamond, graphite, and carbon and the influence of surface films

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1951.0173 ◽

1951 ◽

Vol 208 (1095) ◽

pp. 444-455 ◽

Cited By ~ 131

Keyword(s):

Shear Strength ◽

Large Scale ◽

Physical Adsorption ◽

Surface Films ◽

Low Friction ◽

Real Area Of Contact ◽

Carbon And Graphite ◽

Strong Adhesion ◽

Frictional Behaviour ◽

Real Area

This paper describes an experimental study of the frictional behaviour of diamond, graphite and of carbon which have been outgassed in vacuo . The removal of surface films which are normally present causes a large increase in the friction. The admission of a small amount of oxygen, water vapour or other contaminant will reduce the friction. Both physical adsorption and chemical adsorption are important. There is evidence that with clean graphite surfaces there is strong adhesion at the interface, so that when sliding takes place slip and shearing occurs beneath the surface. Carbon and graphite have a negative tem perature coefficient of friction. The low friction normally observed with diamond is due to the presence of adsorbed oxygen and other gases. The friction of clean diamond on diamond is high, and the shear strength at the interface is comparable with the shear strength of diamond. Large-scale seizure does not occur because the deformation of the diamond in the region of contact is elastic and the real area of contact necessarily remains small.

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Surface Wave Propagation in Thin Silver Films under Residual Stress

Zeitschrift für Naturforschung A ◽

10.1515/zna-2002-1-208 ◽

2002 ◽

Vol 57 (1-2) ◽

pp. 58-64

Author(s):

A. Njeh ◽

D. Schneider ◽

H. Fuess ◽

M. H. Ben Ghozlen

Keyword(s):

Residual Stresses ◽

Phase Velocity ◽

Surface Waves ◽

Acoustic Waves ◽

Surface Acoustic Waves ◽

Dispersion Curves ◽

Silver Films ◽

Surface Wave Propagation ◽

Relative Change ◽

Good Agreement

Investigations using surface acoustic waves provide information on the elastic properties of thin films. Residual stresses change the phase velocity of the surface waves. We have calculated the phase velocity and dispersion of surface waves in thin silver films with a strong [111]-fibre texture. A non-linear description of surface waves propagating along the [110]-direction of the substrate has been developed on the basis of an acoustoelastic theory, taking into account residual stresses. The relative change Δc/c of the velocity v was found to be linear for large excitation frequencies. The dispersion curves were measured using a photoacoustic method. For sputtered polycrystalline thin silver films we found good agreement between the experimental and calculated dispersion curves for frequencies up to 225 MHz

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Surface Wave Propagation in Thin Silver Films under Residual Stress

Zeitschrift für Naturforschung A ◽

10.1515/zna-2002-9-1008 ◽

2002 ◽

Vol 57 (9-10) ◽

pp. 58-64

Author(s):

A. Njeh ◽

T. Wieder ◽

D. Schneider ◽

H. Fuess ◽

M. H. Ben Ghozlen

Keyword(s):

Residual Stresses ◽

Phase Velocity ◽

Surface Waves ◽

Acoustic Waves ◽

Surface Acoustic Waves ◽

Dispersion Curves ◽

Silver Films ◽

Surface Wave Propagation ◽

Relative Change ◽

Good Agreement

Investigations using surface acoustic waves provide information on the elastic properties of thin films. Residual stresses change the phase velocity of the surface waves. We have calculated the phase velocity and dispersion of surface waves in thin silver films with a strong [111]-fibre texture. A non-linear description of surface waves propagating along the [110]-direction of the substrate has been developed on the basis of an acoustoelastic theory, taking into account residual stresses. The relative change Δv/v of the velocity v was found to be linear for large excitation frequencies. The dispersion curves were measured using a photoacoustic method. For sputtered polycrystalline thin silver films we found good agreement between the experimental and calculated dispersion curves for frequencies up to 225 MHz.

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Sound-driven single-electron transfer in a circuit of coupled quantum rails

Nature Communications ◽

10.1038/s41467-019-12514-w ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 11

Author(s):

Shintaro Takada ◽

Hermann Edlbauer ◽

Hugo V. Lepage ◽

Junliang Wang ◽

Pierre-André Mortemousque ◽

...

Keyword(s):

Quantum Logic ◽

Integrated Circuit ◽

Acoustic Waves ◽

Large Scale ◽

Piezoelectric Materials ◽

Surface Acoustic Waves ◽

Logic Gates ◽

Building Blocks ◽

Single Electron ◽

Single Shot

Abstract Surface acoustic waves (SAWs) strongly modulate the shallow electric potential in piezoelectric materials. In semiconductor heterostructures such as GaAs/AlGaAs, SAWs can thus be employed to transfer individual electrons between distant quantum dots. This transfer mechanism makes SAW technologies a promising candidate to convey quantum information through a circuit of quantum logic gates. Here we present two essential building blocks of such a SAW-driven quantum circuit. First, we implement a directional coupler allowing to partition a flying electron arbitrarily into two paths of transportation. Second, we demonstrate a triggered single-electron source enabling synchronisation of the SAW-driven sending process. Exceeding a single-shot transfer efficiency of 99%, we show that a SAW-driven integrated circuit is feasible with single electrons on a large scale. Our results pave the way to perform quantum logic operations with flying electron qubits.

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Introduction to the discussion: the mechanism of friction

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1952.0093 ◽

1952 ◽

Vol 212 (1111) ◽

pp. 440-449 ◽

Cited By ~ 16

Keyword(s):

Large Scale ◽

Surface Films ◽

Local Pressure ◽

Large Measure ◽

Thermo Electric ◽

The Real ◽

Real Area Of Contact ◽

Rough Approximation ◽

Local Surface Temperature ◽

Real Area

The application of the electron microscope, and of metallurgical, interferometric and other physical methods, shows that even carefully polished or cleaved surfaces have irregularities on them which are large compared with molecular dimensions. When two solids are placed together, the real area of contact is very small, so that the local pressure is high and, in general, exceeds the yield pressure, p m , of the metal. Plastic flow of the solid occurs at the summits of the irregularities so that the real area of contact A is proportional to the applied load W , i.e. A = W / p m . There is adhesion at these local regions of contact and the friction is, in a large measure, the force required to shear them. As a rough approximation F = As , where s is the shear strength of the junctions. Since A is proportional to W and independent of the size of the surfaces, this can explain the classical laws of friction. The mechanism of this process has been studied by optical and metallurgical methods and by the use of artificially radioactive metals. The strength and nature of the adhesion between metals is profoundly influenced by the oxide films which are normally present on them. It is the presence of these films which enables sliding to occur. If these surface films are removed in high vacuo and naked metals are placed in contact, there is strong adhesion—an attempt to slide them may cause further plastic deformation with consequent increase in the area of contact—and a large-scale ‘cold welding’ of the metals. If the sliding speed is appreciable, the temperature at the local points of rubbing contact will be raised. These surface temperatures have been measured by a thermo-electric method, by a visual or photographic method and by the use of an infra-red cell. All three methods give similar results and show that even at moderate speeds the local surface temperature may easily exceed 1000° C. It is limited by the melting of the metal. These high temperatures play an important part in polishing, the formation of the Beilby layer, the machining of metals and a number of other physical processes. Some low-friction materials are also described.

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Contactless Liquid Height and Property Estimation Using Surface Acoustic Waves

Acoustics ◽

10.3390/acoustics2020021 ◽

2020 ◽

Vol 2 (2) ◽

pp. 366-381

Author(s):

Hani Alhazmi ◽

Rasim Guldiken

Keyword(s):

Acoustic Waves ◽

Wave Amplitude ◽

Surface Acoustic Waves ◽

Experimental Studies ◽

Wave Mode ◽

Propagation Path ◽

Liquid Volume ◽

Time Frequency ◽

Reflected Wave ◽

Solid Plate

The propagation of surface acoustic waves over a solid plate is highly influenced by the presence of liquid media on the surface. At the solid–liquid interface, a leaky Rayleigh wave radiates energy into the liquid, causing a signification attenuation of the surface acoustic wave amplitude. In this study, we take advantage of this spurious wave mode to predict the characteristics of the media, including the volume or height. In this study, the surface acoustic waves were generated on a thick 1018 steel surface via a 5 MHz transducer coupled through an angle beam wedge. A 3D-printed container was inserted on the propagation path. The pulse-echo time-domain responses of the signal were recorded at five different volumes (0, 400, 600, 1000, and 1800 µL). With the aid of parametric CAD analysis, both the position and distance of the entire traveling wave in the liquid layer were modeled and verified with experimental studies. The results indicated that the average drop in the reflected wave amplitude due to liquid loading is −62.5% compared to the empty container, with a percentage of error within 10% for all cases. The localized-time frequency components of the reflected wave were obtained via a Short-Time Fourier Transform technique. Up to 10% reduction (500 KHz) in the central frequency was observed due to the liquid volume increasing. The method discussed herein could be useful for many applications, where some of the liquid’s parameters or the ultrasonic wave behavior in the liquid need to be assessed.

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Characterization of RF Sputtered ZnO Piezoelectric Films Using Transmission Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100114050 ◽

1975 ◽

Vol 33 ◽

pp. 86-87

Author(s):

Kemining W. Yeh ◽

Richard S. Muller ◽

Wei-Kuo Wu ◽

Jack Washburn

Keyword(s):

Integrated Circuit ◽

Acoustic Waves ◽

New Technology ◽

Surface Acoustic Waves ◽

Electromechanical Properties ◽

Leading Role ◽

Saw Devices ◽

Transmission Electron ◽

High Degree

Considerable and continuing interest has been shown in the thin film transducer fabrication for surface acoustic waves (SAW) in the past few years. Due to the high degree of miniaturization, compatibility with silicon integrated circuit technology, simplicity and ease of design, this new technology has played an important role in the design of new devices for communications and signal processing. Among the commonly used piezoelectric thin films, ZnO generally yields superior electromechanical properties and is expected to play a leading role in the development of SAW devices.

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