Symbol	Description	Unit
AIR(z)	Contact area of the inner sealing ridge under deformation	mm2
APmax(z)	Area of the maximal pore as a function of ridge immersion	mm2
ATmax, AVmax	Maximum cross-sectional areas of the top peak and the valley peak, respectively	mm2
b(z)	Contact width of the inner sealing ridge	mm
B 0	Linear strain–displacement transformation matrix	no unit
B L	Linear strain–displacement transformation matrix, which depends on the displacement	no unit
B N	Nonlinear strain–displacement transformation matrix	no unit
D, Df	Fractal dimension and fractal dimension of tortuous capillaries, respectively	no unit
D	Elasticity matrix	no unit
E, Eu	Young modulus, elastic, and tangent in plastic zone, respectively	MPa
G	Fractal roughness constant	no unit
h	Height of the porous structure	mm
K 0	Small displacement stiffness matrix	no unit
K d	Large displacement stiffness matrix	no unit
K T	Tangent stiffness matrix	no unit
KV	Permeability	mm2
K σ	Initial stress matrix dependent on the stress level	no unit
lTmax, lVmax	Base lengths of the maximum top peak and valley peak, respectively	mm
L	Sample length	mm
n	Frequency index of asperities	no unit
M	Number of superposed ridges	no unit
po, pt	Pressure inside and outside of the cylinder, respectively	MPa
PPmax(z)	Perimeter of the pore as a function of ridge immersion	mm
PTmax, PVmax	Perimeters of the maximum top peak and valley peak, respectively	mm
Qm	Mass flow per perimeter	mg/(s·m)
ri, ro, rIRi, rIRo, rIRm, rAV	Radius, inner, outer, and inner of the inner ridge, outer of the inner ridge, mean of the inner ridge, and average radius of the cylinder, respectively	mm
Rp 02	Yield strength	MPa
S	Cross-section of the flow	mm2
S	Piola–Kirchhoff second stress tensor	no unit
T	Temperature	°C
x, y, z	Coordinates in vertical and horizontal positions, respectively	mm
α	Opening angle of the sealing ridge	°
αc	Coefficient of the thermal expansion	1/°C
δTmax, δVmax	Maximum height of the top peak and valley peak, respectively	mm
ΔF	Difference between applied force and resistance force (vector)	no unit
ΔU	Generalised displacement vector	no unit
ε(z)	Porosity level as a function of ridge immersion	no unit
η	Dynamic viscosity	Pa·s
λmax, λmin	Diameter of the pore, maximum and minimum, respectively	mm
ν	Poisson ratio	no unit
ρ	Fluid density	kg/m3
γ	Frequency spectrum	no unit
τ	Tortuosity of the capillaries	no unit
${\phi }_a$	Random number	no unit