b	exponent of the fatigue limit
bo	exponent of the shear fatigue limit
c	exponent of the plastic fatigue strain
co	exponent of the plastic shear fatigue strain
DPn	damage parameter
E	Young’s modulus of elasticity
G	shear modulus
J	material constant
k	material fitting parameter
Nf	number of cycles to failure
β	coefficient taking into account the best fit for a given material
$d{\epsilon }_{ij}^p$	plastic strain tensor
${\epsilon }_a$	normal strain amplitude
εn*	normal strain excursion between adjacent turning points of the maximum shear strain range on the critical plane
${{\epsilon }^{\prime }}_f$	coefficient of the plastic fatigue strain
$\gamma$	material-dependent exponent
${\gamma }_a$	shear strain amplitude
${{\gamma }^{\prime }}_f$	coefficient of the plastic shear fatigue strain
${\gamma }_{max}$	maximum shear strain
${{\sigma }^{\prime }}_f$	coefficient of the fatigue limit
${\sigma }_{ij}$	stress tensor
σh	hydrostatic stress
${\sigma }_{max}$	maximum normal stress
σu	ultimate strength
σy	yield strength
(στ)max	maximum shear and tensile stress product value
${{\tau }^{\prime }}_f$	shear coefficient of the fatigue limit
${\tau }_{max}$	maximum shear stress
υ	elastic Poisson’s ratio