The stress cracking property was evaluated using the NCLS test, and the test data were subsequently analyzed using the
stress intensity factor K and the J-integral.
Handbook of the
stress intensity factor, Revised edition.
This is the location where a crack was introduced to give the largest
stress intensity factor (KI).
For the fatigue crack growth simulation in Regime III, the constant loading amplitude is applied with [F.sub.max] = 24 kN at R = 0.1, which corresponds to the initial
stress intensity factor range [DELTA] [K.sub.i] = 76 MPa [m.sup.1/2].
The whole
stress intensity factor of breakdown pressure is divided into three parts: [K.sub.1] is the
stress intensity factor of in situ stress; [K.sub.2] is the
stress intensity factor of borehole stress; and [K.sub.3] is the
stress intensity factor in pore stress.
It will help to release (10) and to calculate later the
Stress Intensity Factor (KI) as stated in (13).
Averaging all the results of the tests, critical value of
stress intensity factor [K.sub.Ic] is about 6.76 MPa[square root]m for CT specimens.
The
stress intensity factor of Mode II for the double notch four-point beam due to the external load P, is given by (Guryao, 1996) (Equation 8):
The
stress intensity factors [K.sub.I] and [K.sub.II] at the crack tip can be used to obtain the geometric correction factors [F.sub.I[theta]](a/h) and [F.sub.II[theta]](a/h).