High-speed Digital Imaging and Computational Modeling of Hybrid Metal-Composite Plates Subjected to Water-based Impulsive Loading

2015 ◽  
Vol 56 (4) ◽  
pp. 545-567 ◽  
Author(s):  
S. Avachat ◽  
M. Zhou
Keyword(s):  
Computational Modeling ◽  
Digital Imaging ◽  
High Speed ◽  
Composite Plates ◽  
Impulsive Loading ◽  
Metal Composite ◽  
Water Based

The bright future of digital imaging in scanning electron microscopy

1993 ◽  
Vol 51 ◽  
pp. 768-769
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Digital Imaging ◽  
High Speed ◽  
High Performance ◽  
Mass Storage ◽  
Analog To Digital ◽  
Central Processing ◽  
Digital Imaging Technology ◽  
Scanning Electron

One of the major advancements applied to scanning electron microscopy (SEM) during the past 10 years has been the development and application of digital imaging technology. Advancements in technology, notably the availability of less expensive, high-density memory chips and the development of high speed analog-to-digital converters, mass storage and high performance central processing units have fostered this revolution. Today, most modern SEM instruments have digital electronics as a standard feature. These instruments, generally have 8 bit or 256 gray levels with, at least, 512 × 512 pixel density operating at TV rate. In addition, current slow-scan commercial frame-grabber cards, directly applicable to the SEM, can have upwards of 12-14 bit lateral resolution permitting image acquisition at 4096 × 4096 resolution or greater. The two major categories of SEM systems to which digital technology have been applied are:In the analog SEM system the scan generator is normally operated in an analog manner and the image is displayed in an analog or "slow scan" mode.

scholarly journals Shock Tube as an Impulsive Application Device

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Soumya Ranjan Nanda ◽  
Sumit Agarwal ◽  
Vinayak Kulkarni ◽  
Niranjan Sahoo
Keyword(s):  
Heat Transfer ◽  
Shock Tube ◽  
High Speed ◽  
Force Measurement ◽  
Peak Load ◽  
Wave Force ◽  
Impulsive Loading ◽  
Force Balance ◽  
Test Model ◽  
Impulse Facility

Current investigations solely focus on application of an impulse facility in diverse area of high-speed aerodynamics and structural mechanics. Shock tube, the fundamental impulse facility, is specially designed and calibrated for present objectives. Force measurement experiments are performed on a hemispherical test model integrated with the stress wave force balance. Similar test model is considered for heat transfer measurements using coaxial thermocouple. Force and heat transfer experiments demonstrated that the strain gauge and thermocouple have lag time of 11.5 and 9 microseconds, respectively. Response time of these sensors in measuring the peak load is also measured successfully using shock tube facility. As an outcome, these sensors are found to be suitable for impulse testing. Lastly, the response of aluminum plates subjected to impulsive loading is analyzed by measuring the in-plane strain produced during deformation. Thus, possibility of forming tests in shock is also confirmed.

Vocal Fold Vibratory Characteristics in Normal Female Speakers From High-Speed Digital Imaging

2012 ◽  
Vol 26 (2) ◽  
pp. 239-253 ◽  
Author(s):  
Kartini Ahmad ◽  
Yuling Yan ◽  
Diane M. Bless
Keyword(s):  
Digital Imaging ◽  
Vocal Fold ◽  
High Speed ◽  
Normal Female

scholarly journals Relation between Voice Quality and Pathological Vibratory Patterns Using High-Speed Digital Imaging.

1999 ◽  
Vol 102 (3) ◽  
pp. 354-367 ◽  
Author(s):  
Mamiko Miyaji ◽  
Yoshitake Iwamoto ◽  
Makoto Oda ◽  
Seiji Niimi
Keyword(s):  
Digital Imaging ◽  
High Speed ◽  
Voice Quality

Estimation of glottal area function using stereo-endoscopic high-speed digital imaging

2010 ◽  
Author(s):  
Hiroshi Imagawa ◽  
Ken-Ichi Sakakibara ◽  
Isao T. Tokuda ◽  
Mamiko Otsuka ◽  
Niro Tayama
Keyword(s):  
Digital Imaging ◽  
High Speed ◽  
Area Function

Two-dimensional computational modeling of high-speed transient flow in gun tunnel

Shock Waves ◽  
2017 ◽  
Vol 28 (2) ◽  
pp. 335-348 ◽  
Author(s):  
A. M. Mohsen ◽  
M. Z. Yusoff ◽  
H. Hasini ◽  
A. Al-Falahi
Keyword(s):  
Computational Modeling ◽  
High Speed ◽  
Transient Flow ◽  
Two Dimensional

Subsonic and Intersonic Failure of Composites: High-Speed Optical and Thermographic Measurements and Numerical Simulations

2000 ◽  
Author(s):  
A. J. Rosakis ◽  
D. Coker ◽  
C. Yu ◽  
M. Ortiz
Keyword(s):  
Crack Growth ◽  
High Speed ◽  
Large Scale ◽  
Wave Speed ◽  
Epoxy Composite ◽  
Shear Crack ◽  
Crack Tip ◽  
Composite Plates ◽  
Crack Face ◽  
Shear Wave Speed

Abstract In this paper dynamic fracture behavior of unidirectional graphite-epoxy composite plates is investigated experimentally and numerically. Crack propagation experiments are conducted on thick unidirectional graphite-epoxy composite plates subjected to in-plane, symmetric and asymmetric, impact loading. The coherent gradient sensing technique (CGS) is used in conjunction with high-speed photography to visualize the crack growth events. Cracks are found to propagate at subsonic speeds in the Mode-I case, whereas in both mixed mode and Mode-II the crack tip speed clearly exceeds the shear wave speed of the laminate. In the case of symmetric loading (Mode-I), the crack tip speeds approach the Rayleigh wave speed of the composite (1500 m/s), however it never exceeds it as predicted by asymptotic analysis. The situation is found to be entirely different for growing shear (Mode-II) cracks. A shock wave emanating from the crack tip is observed in the optical patterns. This provides direct evidence that the crack propagates faster than the shear wave speed of the composite. The crack tip speed is then observed to jump to a level close to the axial longitudinal wave speed along the fibers (7500 m/s) and then to stabilize to a lower level of approximately 6500 m/s. This speed corresponds to the speed at which the energy release rate required for shear crack growth is non-zero as determined from asymptotic analysis. The CGS interferograms also reveal the existence of large-scale frictional contact of the crack faces behind the moving shear cracks. In addition high speed thermographic measurements are conducted that show concentrated hot spots behind the crack tip indicating crack face frictional contact. Finally, these experiments are modeled by a detailed dynamic finite element calculation involving cohesive elements, newly developed adaptive remeshing using subdivision and edge collapse, composites element, and penalty contact. The numerical calculations are calibrated on the basis of fundamental material properties measured in the laboratory. The numerical methodology is subsequently validated by direct comparison to optical experimental measurements (crack speed record and near tip deformation field structure). For shear crack growth the numerics also reveal the experimentally observed shock wave structure and confirm the optical observation of large-scale crack face contact.

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