Fatigue Crack Paths 2003

H(H—h)

r0+h

J. 6 y ( r _ r 0 ) d r : 6 n o m g r o s s 2 onomgmss being the nominal stress on the gross area. By intr ducing Eq. 8 into Eqs 13-14

one obtains

701-1

111-1

J-ru+h

(Smax

l _ r — r 0 4 (q_l) 1+atan[(r—r0)m] + q ® li dr:

r0

4(q—1)+q0)l

K

rom

r0

: G n ogrmoss

(15)

JIYU'I'I

omax

1 _ r — r 0 4 (q_1) 1+atan[(r—r0)m]Ml +

Yo

4(q—l)+q0)l

K

rom

111-1

h

H H — h

} ( 2 +_r r0 ) d r : 6 n o m g r o s s

Such equations allow us to determine m and K.

Plate with an edge notch subjected to three point bending (PEN)

In three point bending, it is expected that a localised perturbing effect is provoked on

the weakenedsection by the presence of the force F. O n the other hand, only positive

stresses on the opposite side are really important for crack propagation and their

distribution mainly depends on the notch effect.

Thetwo equilibrium conditions, adapted to this load case, are:

J-ro+h(jyd r z o

r0 +h

h 2

6 y ( r _ r 0 ) d r : 6 n o m n e t ?

r0

In a more explicit form:

1

-

t [( — l l "-1

W1

‘[10 6 m — a x { 1 _ r r 0 ] 1

+q(,t)l i d I ' I O

+

r1

4(q-1)+q0)l

K

form

10