scholarly journals Shear waves generation by mode conversion in picosecond ultrasonics: Impact of grain orientation and material properties

2020 ◽  
Author(s):  
Yuzhou Wang ◽  
Marat Khafizov
Keyword(s):  
Material Properties ◽  
Grain Orientation ◽  
Mode Conversion ◽  
Shear Waves ◽  
Picosecond Ultrasonics

scholarly journals On the propagation, reflection, and transmission of transient cylindrical shear waves in nonhomogeneous four-parameter viscoelastic media

1973 ◽  
Vol 8 (3) ◽  
pp. 397-411 ◽  
Author(s):  
T. Bryant Moodie
Keyword(s):  
Material Properties ◽  
Outer Boundary ◽  
Shear Waves ◽  
Infinite Plate ◽  
Radial Distance ◽  
Viscoelastic Plate ◽  
Reflection And Transmission ◽  
Viscoelastic Media ◽  
Finite Plate ◽  
Arbitrary Thickness

The purpose of this paper is to study the propagation of cylindrical shear waves in nonhomogeneous four-parameter viscoelastic plates of arbitrary thickness. The plates have a transverse cylindrical hole and their material properties are functions of the radial distance from the center of this opening. They are initially unstressed and at rest. A suddenly rising shearing traction is applied uniformly over the boundary of the opening and parallel to the faces of the plates and thereafter steadily maintained; they are otherwise free from loading. We consider both the case of a finite plate with a stress-free cylindrical outer boundary, and an infinite plate composed of two media in welded contact along a cylindrical surface symmetrical with respect to the center of the opening. We find that a reflected pulse is produced at the outer boundary of the finite plate while reflected and transmitted pulses are produced at the interface in the infinite bi-viscoelastic plate. Ray techniques are used throughout, and formal asymptotic wavefront expansions of the solution functions are obtained.

VSP measurement of shear‐wave velocities in consolidated and poorly consolidated formations

Geophysics ◽  
1992 ◽  
Vol 57 (12) ◽  
pp. 1583-1592 ◽  
Author(s):  
John O’Brien
Keyword(s):  
Shear Wave ◽  
Poisson’S Ratio ◽  
Mode Conversion ◽  
Shear Waves ◽  
Vertical Motion ◽  
Seismic Source ◽  
Poisson's Ratio ◽  
The Arctic ◽  
Wave Velocities ◽  
Shear Wave Velocities

Mode conversion in the subsurface can generate shear waves with sufficient amplitude so that they can be used to measure shear‐wave propagation effects. Significant mode conversion can occur even at near vertical incidence if there is sufficient contrast in Poisson’s ratio across the interface. This can be exploited to measure shear‐wave velocities in the underlying section in the course of vertical seismic profile (VSP) acquisition. The technique is effective even in poorly consolidated formations with low shear‐wave velocities where sonic waveform logging fails. Where shear‐wave velocity data are available from sonic waveform logs, the VSP data can be used to verify the wireline data and to calibrate these data to seismic frequencies. The technique is illustrated with a case study from the North Slope, Alaska, in which several shear‐wave events are observed propagating downward through the subsurface. The seismic source is a vertical‐motion vibrator; shear waves are generated via mode conversion in the subsurface and also radiated from the source at the surface, and they are observed with both far‐ and near‐source offsets. The shear‐wave events are strong even on the near‐offset data, which is attributed to the contrast in Poisson’s ratio at the interfaces where mode conversion occurs. The technique is not limited to the hard surfaces of the Arctic and should work in any well, either land or marine, that penetrates shallow interfaces where mode conversion can occur.

The free shock wave as a seismic source

1995 ◽  
Vol 450 (1939) ◽  
pp. 351-370
Keyword(s):  
Shock Wave ◽  
Mode Conversion ◽  
Shear Waves ◽  
Incident Shock ◽  
Seismic Survey ◽  
Physical Parameters ◽  
Wave System ◽  
Wave Source ◽  
Simultaneous Generation ◽  
Free Shock

The free shock wave has particular advantages as a source for seismic survey. Its physical parameters can be precisely defined and its interaction with the rock environment predicted. In particular, the wave mode conversion which occurs leads to the simultaneous generation of both strong compression and shear waves in the rock matrix. The first part of the present study outlines the basic principles of design for a source that will generate, repetitively, free shock waves with associated pressure fields that range over two orders of magnitude (measured in bars). The second part of the paper describes the wave system which develops when shocks, generated by such a source, interact with water in, for example, a water-filled surface bore-hole. The multiplication of incident shock pressure in water, which is characteristic of the operational performance of the shock-wave source, is shown to be a consequence of the complex interactions that take place between wave systems transmitted and reflected at the gas-water interface and those that are reflected at the water-solid interface. The third part of the paper illustrates the behaviour of compressional and shear waves generated by the shock-wave source in both sedimentary rock and granite. It is shown that the mode conversion to compressional and shear waves in granite leads to near-ideal behaviour in terms of the ratio of velocities of propagation for the two types of wave in the rock.

Numerical Investigation of Propagation of Ultrasonic Waves in the Waveguides with Mode Conversion

2013 ◽  
Vol 543 ◽  
pp. 219-222
Author(s):  
Elena Jasiūnienė ◽  
Egidijus Žukauskas ◽  
Rymantas Kažys
Keyword(s):  
Numerical Investigation ◽  
Longitudinal Wave ◽  
Mode Conversion ◽  
Incidence Angle ◽  
Ultrasonic Transducer ◽  
Shear Waves ◽  
Ultrasonic Waves ◽  
Ultrasonic Transducers ◽  
Special Cases ◽  
Longitudinal And Shear Waves

Ultrasonic investigation techniques are widely used in materials characterisation and non-destructive testing applications. In special cases of applications, such as investigation of properties of melted polymers, metals and hot liquids, measurements must be performed in a wide temperature range. However conventional piezoelectric transducers cannot withstand higher temperatures than the Curie temperature. Therefore in order to protect conventional ultrasonic transducers from influence of a high temperature and to avoid depolarization, measurements must be performed using special waveguides with a low thermal conductivity between the object under investigation and the ultrasonic transducer. For measurements of the material properties, such as viscoelastic properties of materials, additional shear wave transducers must be used. In this work approach how to excite both, longitudinal and shear waves using special waveguides with mode conversion, using pair of conventional ultrasonic longitudinal wave transducers is presented. In this work numerical investigation of propagation of longitudinal and shear ultrasonic waves in the waveguides with mode conversion using finite element method and CIVA software was carried out. Modelling of propagation of simultaneously generated longitudinal and shear waves using pair of longitudinal ultrasonic transducers was performed. Influence of temperature gradient to the required incidence angle of the longitudinal wave was evaluated.

Understanding and Controlling Cu Protrusions in 3D TSV Processing

2012 ◽  
Vol 2012 (1) ◽  
pp. 000023-000030
Author(s):  
Seth Kruger ◽  
Klaus Hummler ◽  
Robert Geer ◽  
Kathleen Dunn ◽  
Colin McDonough ◽  
...  
Keyword(s):  
Material Properties ◽  
Grain Orientation ◽  
Room Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Electron Backscatter ◽  
Main Factors ◽  
Underlying Mechanisms ◽  
On Chip ◽  
Silicon Vias ◽  
Secondary Ion

Cu-filled through-silicon vias (TSVs) are an essential building block of 3D and 2.5D integrated chips. In the TSV-mid processing flow, which has emerged as an industry mainstream, one or more on-chip wiring levels are formed after the TSV Cu fill is completed, which exposes the fill to peak temperatures of up to 400 °C. Due to the higher coefficient of thermal expansion (CTE) of Cu than the surrounding silicon and dielectrics, the TSV fill protrudes above the level previously defined by the TSV chemical mechanical polishing (CMP) step. Even after returning to room temperature, the top of the TSV will not occupy the same space due to plastic deformation during the thermal treatment. This phenomenon is known as Cu protrusions, pumping, or popping. Excessive amounts of Cu protrusion present a risk to yields and reliability because the expansion can damage dielectrics and wiring above or adjacent to the TSVs. In this study, we report the underlying mechanisms as well as process remedies for Cu protrusions. The SEMATECH 5 um × 50 um TSV process and learning vehicle is used to conduct process split experiments comparing various plating chemistries, plating recipes, and post-plating anneal conditions. Stresses in the surrounding silicon are studied by micro-Raman, and a distinct signature distinguishing good from bad Cu protrusion behavior is identified. Cu material properties such as contamination, grain size, grain orientation, and strain may also influence the protrusion behavior; these factors are studied by micro-secondary ion mass spectroscopy (SIMS) and electron backscatter spectroscopy (EBSD). Our results shows that the choice of plating chemistry and subsequent optimized post-plating anneal are the main factors in suppressing Cu protrusions. Our best known method is able to reduce Cu protrusions to about 15 nm after typical thermal loads.

Three-Dimensional Dynamic Response of Buried Pipelines to Incident Longitudinal and Shear Waves

1985 ◽  
Vol 52 (4) ◽  
pp. 919-926 ◽  
Author(s):  
S. K. Datta ◽  
P. M. O’Leary ◽  
A. H. Shah
Keyword(s):  
Material Properties ◽  
Shear Waves ◽  
Three Dimensional ◽  
Buried Pipelines ◽  
Incident Plane ◽  
Longitudinal And Shear Waves ◽  
Induced Stresses ◽  
Dynamic Amplification ◽  
Hoop Stresses ◽  
Surrounding Soil

An exact analysis is presented here for the three-dimensional dynamics of a long continuous pipeline embedded in an elastic medium. A shell model of the pipe has been used here. It is shown that the dynamic amplification of axial and hoop stresses induced in the pipe due to incident plane longitudinal and shear waves depends crucially on the ratio of rigidities of the surrounding soil and the pipe. Induced stresses are also found to have appreciable frequency dependence for certain combinations of material properties and angles of incidence. Results presented here are also applicable to buried tunnels.

Effect of Timber Grain Orientation on Bonded-In Rod Connection Systems

2012 ◽  
Vol 517 ◽  
pp. 695-704
Author(s):  
Hannah Pearson ◽  
Mark Evernden ◽  
Richard Harris
Keyword(s):  
Failure Criterion ◽  
Material Properties ◽  
Grain Orientation ◽  
Maximum Stress ◽  
Tensile Behavior ◽  
Plate Structures ◽  
Stress Theory ◽  
Pull Out ◽  
Connection System ◽  
Timber Products

Presented in this paper are the results of practical tests to determine some key material properties of engineered timber, in particular glulam. The results are discussed and compared with three known failure criterion, Hankinsons formula, The Tsai-Wu criterion and Maximum stress theory to determine if they are appropriate models for predicting the properties of glulam. The properties considered have been chosen with respect to a connection system for use in folded plate structures utilizing embedded rods. This paper considers the effect of the timber grain angle on the compression, tensile and steel dowel rod pull-out strengths. The test data shows that Hankinson and Tsai-Wu are both good models to predict both the compression and tensile behavior of engineered timber products at non-tangential angles, whereas maximum stress theory had less correlation and over predicts the results and would not be recommended for use in engineered timber materials.

Seismic shear‐wave observations in a physical model experiment

Geophysics ◽  
1983 ◽  
Vol 48 (6) ◽  
pp. 688-701 ◽  
Author(s):  
Robert H. Tatham ◽  
Donald V. Goolsbee ◽  
Wulf F. Massell ◽  
H. Roice Nelson
Keyword(s):  
Reflection Coefficient ◽  
Physical Model ◽  
Shear Wave ◽  
Model Experiment ◽  
Mode Conversion ◽  
Shear Waves ◽  
P Wave ◽  
Wave Reflections ◽  
Sea Floor ◽  
Physical Model Experiment

The observation and common‐depth‐point (CDP) processing of mode‐converted shear waves is demonstrated for real data collected in a physical model experiment. The model, submerged in water, represented water depth scaled to 250 ft, the first subsea reflector at 4000 ft, and the last reflector at 7000 ft below the sea floor with a structural wedge at the center. Very efficient mode conversion, from P to SV and back to P, is anticipated for angles of incidence at the liquid‐solid interface (sea floor) between 35 and 80 degrees. The model, constructed of Plexiglas and 3180 resin, will support elastic shear‐wave propagation. One anticipated problem, internal reflections from the sides of the model, was solved by tapering the sides of the model to 45 degrees off vertical. The P wave reflection coefficient at an interface between Plexiglas and water is 35 percent for vertical incidence, but it diminishes to very nearly zero between 43 and 75 degrees. Thus, by tapering the sides of the model, any undesired internal P wave reflections had to undergo at least two reflections at angles of incidence in the low reflection coefficient range for P waves. Data were collected in both an end‐on CDP mode, with offsets from 1000 ft to 20,000 ft, and a variety of walkaway experiments with scaled ranges from 1000 ft to 31,000 ft. Processing and analysis of the data confirm the existence of mode‐converted shear‐wave reflections in a modeled marine environment. In particular, the S wave reflections from all interfaces are identified on both the 100 percent gathered records and the final stacked records. These SV wave reflections were isolated for stacking by considering those portions of the gathered records, both offset and arrival time, that correspond to optimum angles of incidence. In addition, τ-p processing isolated particular angles of incidence, further confirming the incidence angle‐range criterion. Thus, the desired events are unambiguously identified as mode‐converted shear waves.

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