$\lambda$, ${\lambda }_m$, and ${\lambda }_a$	stretch ratio (elongation), mean, and amplitude, respectively;
${\epsilon }_E$	engineering (nominal) strain
${\epsilon }_{G-\mathrm{L}}$	Green–Lagrange strain,
${\epsilon }_{A-E}$	Almansi–Euler strain
${\epsilon }_{\mathrm{L}}$	logarithmic strain
${\epsilon }_o$	octahedral shear strain
$E_{ij}(i,j=1,2,3)$	strain components of Green–Lagrange strain tensor $E$
${\epsilon }_f$	effective tensile strain criterion
${\epsilon }_{fi}(i=1,2,3)$	principal components of ${\epsilon }_f$
${\sigma }_{\max }$	maximum eigenvalue of the Cauchy stress tensor
da/dN	crack growth rate where the crack length is a and the number of cycles is N
Tmax	the maximum tearing energy
U	internal energy stored in the component
A	crack area of a single fracture surface
$W$ and $W_c$	SED and CED, respectively
R-ratio (Rγ, Rε, Rδ or Rθ)	ratio of minimum to maximum load during one cycle
δ and θ	displacement and twist/rotation, respectively
P and T	axial load and torque, respectively
$\gamma$, ${\gamma }_m$, and ${\gamma }_a$	shear strain (the twist per unit length), mean value, and amplitude, respectively
$\omega$	the signal frequency
$\phi$	the phase angle between extension and twist
B	stretch biaxiality ratio (defined as the ratio of log of transverse principal stretch to log of maximum principal stretch)
S–N	stress versus number of cycles to failure
E*	complex modulus
CB	carbon black
HF	hemp fiber
MREs	magnetorheological elastomers
MR	magnetorheological
EOMt	expanded organo-montmorillonite
SR	silicone rubber
NR	natural rubber
SBR	styrene butadiene rubber
SED	strain energy density
CED	cracking energy density
EPDM	ethylene propylene diene monomer rubber
FEA	finite element analysis
ERR	energy release rate
TE	tearing energy
SWT	Smith–Watson–Topper
CXH	Chen–Xu–Huang
CMA	configurational mechanics approach
CPA	critical plane approach
CLD	constant life diagram
1D, 3D, 6D	one-, three-, six-dimensional
CDM	continuous damage mechanics
SENT	single-edged notched tension specimen
LEFM	linear elastic fracture mechanics
MCS	Monte Carlo simulation
ML	machine learning
ISSA-SVR	improved sparrow search algorithm and the support vector regression
BPNN	back-propagation neural network
ISCA	improved sine–cosine algorithm
SVM	support vector machine
CR	polychloroprene rubber
AN2 and AN5	cylindrical hourglass-shaped specimens with notch radii equal to 1.75 and 4.75 mm, respectively.
AE2 and AE42	axisymmetric specimens with curvature radii equal to 2 and 42 mm, respectively.
DENT	double edge notched tension specimen
CCT	center cracked tension specimen
PS	pure shear or planar tension specimen with or without a precut
phr	parts per hundred rubber
NBR	nitrile butadine rubber
CIP	carbonyl iron powder/particle