t′	Corresponding crack path length
Fx′,i	Nodal forces at nodal position i along the crack path
y	Distance in the direction of cracking at the nodal point
σs	Structural stress
σm	Membrane stress
σb	Bending stress
α	Angular misalignment
R	Stress ratio
N	Fatigue life
$t$	Plate thickness
$l$	Crack depth
$t_1$	Given gap depth
${\sigma }_m^t$	Far field membrane stress
${\sigma }_b^t$	Far field bending stress
$p_m$	Membrane stress on the crack surface
$p_b$	Bending stress on the crack surface
$p_s$	Structural stress on the crack surface
$\sigma$	Stress at the node