scholarly journals Characterization of Shear Horizontal Waves Using a 1D Laser Doppler Vibrometer

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2467
Author(s):  
Alaa Elhady ◽  
Eihab M. Abdel-Rahman
Keyword(s):  
Acoustic Waves ◽  
Surface Deformation ◽  
Plane Surface ◽  
Poisson Ratio ◽  
Surface Acoustic Waves ◽  
Laser Doppler Vibrometer ◽  
Element Analysis ◽  
Out Of Plane ◽  
Plane Displacement ◽  
Shear Horizontal

We developed a new technique for the detection of shear horizontal surface acoustic waves (SH-SAW) using a one-dimensional laser-based Doppler vibrometer. It measures the out-of-plane surface deformation at the fingertip of an interdigitated transducer (the boundary of the wave aperture) and uses it to estimate the instantaneous in-plane displacement field given the substrate Poisson ratio. It can also estimate the degree of surface confinement (wave decay rate). The proposed approach was first verified using finite element analysis (FEA) and demonstrated experimentally using a Bleustein–Gulyaev resonator.

Inverse Solution for Bolt Preload Using Surface Deformation

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
A. Zaki ◽  
S. A. Nassar ◽  
S. Kruk ◽  
M. Shillor
Keyword(s):  
Inverse Problem ◽  
Surface Deformation ◽  
Control Method ◽  
Plane Surface ◽  
Joint Surface ◽  
Problem Solution ◽  
Bolted Joint ◽  
Element Analysis ◽  
Out Of Plane ◽  
Axisymmetric Elasticity

In this paper, an inverse biharmonic axisymmetric elasticity problem is solved by invoking measured out-of-plane surface deformation values at discrete locations around a preloaded bolt head, in order to calculate the underhead contact stress and joint clamp load that would have caused that out-of-plane surface deformation. Solution of this type of inverse problem promises to improve the automation process of bolted joint system assembly, especially in critical and safety-related applications. For example, a real-time optically measured joint surface deformation can be utilized for automating process control of bolted joint assembly in a reliable fashion. This would be a significant reliability improvement as compared to the commonly used method in mass production using torque-only control method in which there is wide scatter in the torque–tension correlation due to the normal scatter in frictional variables. Finite element analysis (FEA) method is used to validate the inverse problem solution provided in this paper.

Inverse Solution for Bolt Preload Using Joint Surface Deformation

2013 ◽  
Author(s):  
Amro M. Zaki ◽  
Sayed A. Nassar ◽  
Meyer Shillor ◽  
Serge Kruk
Keyword(s):  
Inverse Problem ◽  
Surface Deformation ◽  
Control Method ◽  
Plane Surface ◽  
Joint Surface ◽  
Problem Solution ◽  
Bolted Joint ◽  
Element Analysis ◽  
Out Of Plane ◽  
Axisymmetric Elasticity

In this paper, an inverse bi-harmonic axisymmetric elasticity problem is solved by invoking measured out-of-plane surface deformation values at discrete locations around a preloaded bolt head, in order to calculate the under head contact stress and joint clamp load that would have caused that out-of-plane surface deformation. Solution of this type of inverse problem promises to improve the automation process of bolted joint system assembly, especially in critical and safety related applications. For example, a real-time optically measured joint surface deformation can be utilized for automating process control of bolted joint assembly in a reliable fashion. This would be a significant reliability improvement as compared to the commonly used method in mass production using torque-only control method in which there is wide scatter in the torque-tension correlation due to the normal scatter in frictional variables. Finite Element Analysis (FEA) method is used to validate the inverse problem solution provided in this paper.

scholarly journals Locally Corroded Stiffener Effect on Shear Buckling Behaviors of Web Panel in the Plate Girder

2015 ◽  
Vol 2015 ◽  
pp. 1-19 ◽  
Author(s):  
Jungwon Huh ◽  
In-Tae Kim ◽  
Jin-Hee Ahn
Keyword(s):  
Corrosion Damage ◽  
Element Analysis ◽  
Buckling Strength ◽  
Lower Shear ◽  
Out Of Plane ◽  
Shear Buckling ◽  
Buckling Failure ◽  
Plane Displacement ◽  
The Web ◽  
Plate Girder

The shear buckling failure and strength of a web panel stiffened by stiffeners with corrosion damage were examined according to the degree of corrosion of the stiffeners, using the finite element analysis method. For this purpose, a plate girder with a four-panel web girder stiffened by vertical and longitudinal stiffeners was selected, and its deformable behaviors and the principal stress distribution of the web panel at the shear buckling strength of the web were compared after their post-shear buckling behaviors, as well as their out-of-plane displacement, to evaluate the effect of the stiffener in the web panel on the shear buckling failure. Their critical shear buckling load and shear buckling strength were also examined. The FE analyses showed that their typical shear buckling failures were affected by the structural relationship between the web panel and each stiffener in the plate girder, to resist shear buckling of the web panel. Their critical shear buckling loads decreased from 82% to 59%, and their shear buckling strength decreased from 88% to 76%, due to the effect of corrosion of the stiffeners on their shear buckling behavior. Thus, especially in cases with over 40% corrosion damage of the vertical stiffener, they can have lower shear buckling strength than their design level.

A Real-Time DSPI System for Measuring Surface Deformation in Clamped Bolted Joints

2008 ◽  
Author(s):  
Aidong Meng ◽  
Sayed A. Nassar
Keyword(s):  
Real Time ◽  
Vibration Isolation ◽  
Surface Deformation ◽  
Plane Surface ◽  
Speckle Pattern ◽  
The Real ◽  
Time Deformation ◽  
Out Of Plane ◽  
Phase Data ◽  
Set Up

A Digital Speckle Pattern Interferometry (DSPI) system is developed for the real-time measuring and monitoring the out-of-plane surface deformation around tightened threaded fasteners that are used to clamp bolted assemblies. Spatial phase shifting is employed to quantitatively determine the distribution of phase data by introducing a spatial carrier fringe pattern to the speckle interferogram. This is achieved by leading the object and reference beams to two separate apertures. The configuration is also suitable for collecting the real-time deformation during bolt tightening. The experimental DSPI system is set-up with optical components on a vibration-isolation table. A Matlab software is developed for the image acquisition and phase data calculation, which yields the out-of-plane surface deformation caused by the bolt preload. An aluminum joint is used with an M12 steel fastener. For miniature screw application, however, a plastic joint is used for collecting data.

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