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Indian Journal of Engineering and Materials Sciences (IJEMS) >
IJEMS Vol.17 [2010] >
IJEMS Vol.17(1) [February 2010] >
| Title: | Mechanoluminescence technique for real-time monitoring of cracks produced during application of loads on crystals |
| Authors: | Chandra, B P
Mahobia, S K
Nema, S K
Jha, P
Kuraria, R K
Kuraria, S R |
| Issue Date: | Feb-2010 |
| Publisher: | CSIR |
| Abstract: |
When a load is applied on
to a crystal, then the fracto- mechanoluminescence (ML) emission takes place in
the form of light pulses. The number of ML pulses and the time duration tc for the appearance of ML
increase with increasing value of the load and the average ML intensity from a
single ML pulse decreases with increasing value of the load. For a given value
of the applied pressure, the total number NT
of ML pulses, the total ML intensity IT
and the time duration tc
of ML emission increase with increasing size of the crystals. As the total ML
intensity is directly related to the area of newly created surfaces, the
pressure dependence of the total ML intensity indicates that initially the
total area of newly created surfaces increases with increasing value of the
applied load and later on it tends to attain a saturation value for higher
values of the applied load. As the strain rate is maximum at a particular time
after the application of load on to a crystal, the rate of the emission of ML
pulses is maximum at a particular time after the application of load on to the
crystals. The dependence of NT,
IT, and tc on the applied pressure Po
follows the following expressions, respectively
NT = Mo Vy
[1 – exp{–δc (Po – Pf)}]
IT = D b Mo V [1 –
exp{–δc (Po
– Pf)}]
and,
tc=1/αln( P0/Pf)
where V is volume of crystal, y is an exponent, δc =1/Pc, Pc is the critical pressure, Pf is the fracture stress, Mo, D, b, and α are constants. A good agreement
is found between the theoretical and experimental results.
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| Page(s): | 61-66 |
| ISSN: | 0975-1017 (Online); 0971-4588 (Print) |
| Source: | IJEMS Vol.17(1) [February 2010]
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