Failure Identification Methodology for Woven Composites Incorporating Sensor Degradation

Materials ◽  
2004 ◽  
Author(s):  
James Pearson ◽  
Mohanraj Prabhugoud ◽  
Mohammed Zikry ◽  
Kara Peters
Keyword(s):  
Experimental Study ◽  
Crack Nucleation ◽  
Fiber Composite ◽  
Bragg Reflection ◽  
Sensor Data ◽  
Woven Composites ◽  
Structural Systems ◽  
Material System ◽  
Sensor Degradation ◽  
Failure Identification

The long-term goal of this project is the development of embedded, optimally distributed, multi-scale sensing methodologies that can be integrated into material systems for failure identification in structural systems. The coupling of sensor data fusion with a three-dimensional predictive framework will provide insight and understanding of events that are difficult, if not impossible, in any experimental study, such as subsurface damage and crack nucleation in structural systems. The current work presents an experimental study of the survivability and degradation behavior of an optical fiber Bragg grating sensor, surface mounted on a woven fiber composite material system during multiple low velocity impacts. The results reveal that as sensor degradation occurs, additional coupling phenomena other than Bragg reflection are observed in the grating sensor. From these additional modes, information on the sensor/host bond and fiber degradation is obtained.

Experimental study on flexural behavior of concrete beam reinforced with GFRP and steel-fiber composite bars

2021 ◽  
pp. 103087
Author(s):  
Shu-Hua Xiao ◽  
Jia-Xiang Lin ◽  
Li-Juan Li ◽  
Yong-Chang Guo ◽  
Jun-Jie Zeng ◽  
...  
Keyword(s):  
Experimental Study ◽  
Concrete Beam ◽  
Steel Fiber ◽  
Fiber Composite ◽  
Flexural Behavior

Reflection of water waves in a channel with corrugated bed

1987 ◽  
Vol 185 ◽  
pp. 249-274 ◽  
Author(s):  
T. Brooke Benjamin ◽  
B. Boczar-Karakiewicz ◽  
W. G. Pritchard
Keyword(s):  
Experimental Study ◽  
Surface Waves ◽  
Water Waves ◽  
Bragg Reflection ◽  
Water Channel ◽  
Sand Bars ◽  
Multiple Processes ◽  
Linearized Theory ◽  
Coastal Sand ◽  
Frictional Effects

Intended as a contribution towards understanding the multiple processes entailed in the development of coastal sand bars due to wave action, this theoretical and experimental study deals with the Bragg reflection of long-crested surface waves in a water channel whose bed is corrugated sinusoidally. The present findings complement and in a few respects improve upon those in previous investigations, particularly Davies & Heathershaw (1984).In §2 a linearized theory is presented, being directed to the elucidation of experimental situations where monochromatic waves propagate into a channel with a limited stretch of corrugations on its bed and an imperfectly absorbing beach at its far end. Allowance is made fully for dispersive effects (§2.2) and approximately for small frictional effects (§2.3). Points of interpretation (§2.4) include accounts of degenerate but non-trivial solutions that apply at frequencies terminating the stopping band, wherein the spatial wavefield has an exponential envelope. The experimental results presented in §4 derive from measurements of the wavefield over a stretch of 24 corrugations, at various frequencies both inside and outside the stopping band. Quantitative comparisons (§4.2 and 4.3) demonstrate close agreements with the theory.

scholarly journals 272 Experimental study of photosensitive material system in female chest Xlay (lst report)

1995 ◽  
Vol 51 (10) ◽  
pp. 1343
Author(s):  
Takashi Shiraki ◽  
Seiji Katoh ◽  
Shirou Yamamoto ◽  
Toshimitsu Kumaki ◽  
Kinji Abe ◽  
...  
Keyword(s):  
Experimental Study ◽  
Material System ◽  
Photosensitive Material

Controlled Initiation of Short Fatigue Cracks in 316L Steel

2005 ◽  
Author(s):  
D. Stefanescu ◽  
J. Marrow ◽  
M. Preuss ◽  
A. Sherry
Keyword(s):  
Experimental Study ◽  
Stainless Steel ◽  
Crack Opening Displacement ◽  
Crack Nucleation ◽  
Fatigue Cracks ◽  
Crack Opening ◽  
Crack Tip ◽  
Image Correlation ◽  
Opening Displacement ◽  
R Ratio

Validation of models for short crack behavior requires accurate measurement of crack opening displacement and crack tip strain fields. Development of reliable measurement procedures, using new techniques such as Image Correlation (IC), requires specimens containing cracks with a well defined geometry. In this paper, results of an experimental study concerning controlled initiation of short fatigue cracks at positive R-ratio in laboratory specimens made from 316L stainless steel are presented. Experimental techniques, including hardness testing and X-ray diffraction were employed in order to investigate the effect of surface preparation on the surface mechanical properties and residual stresses. Crack nucleation is difficult in smooth specimens of 316L austenitic stainless steel at positive R-ratio due to the high fatigue limit and low tensile strength. Specimens with a thin ligament were therefore developed to enable nucleation of a single short fatigue crack. An experimental study of the crack growth aspect ratio evolution was then carried out using a beach marking technique. The technique described in this paper enables single short fatigue cracks of well defined geometry to be nucleated under tensile cyclic loading. Stress corrosion cracks can be developed using the same specimen geometry. Miniature tensile specimens can then be extracted to perform in-situ measurements of the crack opening displacement and crack tip strain field by Image Correlation from Scanning Electron Microscopy observations.

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