IN-SITU MONITORING OF FAILURE MECHANISMS IN BRITTLE MATRIX COMPOSITES USING ACOUSTIC EMISSION AND X-RAY FILM RADIOGRAPHIC TECHNIQUES

1992 ◽  
Vol 8-9 (1-6) ◽  
pp. 879-897 ◽  
Author(s):  
ABHISAK CHULYA ◽  
GEORGE Y. BAAKLINI ◽  
ALEX VARY
Keyword(s):  
Acoustic Emission ◽  
Failure Mechanisms ◽  
In Situ Monitoring ◽  
Matrix Composites ◽  
Brittle Matrix ◽  
X Ray ◽  
Brittle Matrix Composites

The Effects of Voids on the Flexural Properties and Failure Mechanisms of Carbon/Epoxy Composites

2014 ◽  
Vol 71 (2) ◽  
Author(s):  
M. A. Suhot ◽  
Chambers A. R.
Keyword(s):  
Mechanical Properties ◽  
Acoustic Emission ◽  
Flexural Strength ◽  
Failure Mechanisms ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Void Content ◽  
X Ray ◽  
Initiation And Propagation

Although the effect of voids on the mechanical properties of composite failures has been well researched, their effect on the failure mechanisms has not been well characterised. This study investigated the effect of the void content on the flexural strength of carbon/epoxy composites and to explain in terms of the failure mechanisms. The results showed that a 2% increase in void content reduced the flexural strength by 12.7%. Using optical microscopy, X-ray tomography and acoustic emission it was found that voids had no effect upon compression crack initiation but were found to influence the initiation and propagation of delaminations. A combination of in-situ acoustic emission and X-ray tomography proved to be a powerful tool in providing evidence of the failure mechanisms.

Brittle Matrix Composites 8

2006 ◽  
Author(s):  
A.M. Brandt ◽  
V.C. Li ◽  
I.H. Marshall
Keyword(s):  
Matrix Composites ◽  
Brittle Matrix ◽  
Brittle Matrix Composites

Brittle matrix composites 7

2003 ◽  
Author(s):  
A. M. Brandt ◽  
V. C. Li ◽  
I. H. Marshall
Keyword(s):  
Matrix Composites ◽  
Brittle Matrix ◽  
Brittle Matrix Composites

Failure Modes in Brittle Matrix Composites (BMC).

1998 ◽  
Author(s):  
Nicholas J. Pagano ◽  
G. P. Tandon ◽  
R. Y. Kim
Keyword(s):  
Failure Modes ◽  
Matrix Composites ◽  
Brittle Matrix ◽  
Brittle Matrix Composites

scholarly journals In situ monitoring of the influence of water on DNA radiation damage by near-ambient pressure X-ray photoelectron spectroscopy

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Marc Benjamin Hahn ◽  
Paul M. Dietrich ◽  
Jörg Radnik
Keyword(s):  
Dna Damage ◽  
Radiation Damage ◽  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
In Situ Monitoring ◽  
Strong Increase ◽  
Oh Radicals ◽  
Strand Breaks ◽  
X Ray

AbstractIonizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further.

Stochastic Aspects of Matrix Cracking in Brittle Matrix Composites

1993 ◽  
Vol 115 (3) ◽  
pp. 314-318 ◽  
Author(s):  
S. M. Spearing ◽  
F. W. Zok
Keyword(s):  
Matrix Cracking ◽  
Matrix Composites ◽  
Brittle Matrix ◽  
Tensile Response ◽  
Brittle Matrix Composites ◽  
Crack Interactions ◽  
The Matrix ◽  
Interface Slip ◽  
Bridging Fibers

A computer simulation of multiple cracking in fiber-reinforced brittle matrix composites has been conducted, with emphasis on the role of the matrix flaw distribution. The simulations incorporate the effect of bridging fibers on the stress required for cracking. Both short and long (steady-state) flaws are considered. Furthermore, the effects of crack interactions (through the overlap of interface slip lengths) are incorporated. The influence of the crack distribution on the tensile response of such composites is also examined.

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