Issue 51

K. Bahram et alii, Frattura ed Integrità Strutturale, 51 (2020) 467-476; DOI: 10.3221/IGF-ESIS.51.35

K K K

: Effective minimum stress intensity factor.

min eff

: Minimal values of the stress intensity factor during a cycle. : Maximum values of the stress intensity factor during a cycle.

min

max

: Crack length.

a a a

0

: Initial crack length.

0

: crack length.

i

: Material constants of fatigue crack growth.

,  C n

/ da dN da dN da dN / /

: Fatigue crack growth rate.

: Maximum speed / da dN after applying the overload. : Minimum speed / da dN after applying the overload.

max

min



: Describes the state of constraint.

K K R R

: Maximum value of stress intensity factor at the application of overload.

pic

: critical stress intensity factor.

crit

: Maximum value of load ratio at the application of overload.

pic

: Size of the equivalent plastic zone : Effective stress intensity factor range

eq

K  K 

eff

: Stress intensity factor range

: Residual stress intensity factor due to overload

K

R



: The level of residual stress induced by application of overload : The threshold stress intensity factor for a load ratio 0 R 

K 

TH

0

: Critical value of the overload rate resulting in a stop of the propagation of the crack.





SOR

crit

: Maximum load : Minimum load : Young's modulus : Deformation. : overload rate.

P P

max

min

E



τ

476