Page 27 - Materials Science and Engineering An Introduction

List of Symbols • xxiii

P r = dielectric constant or relative s¿ m = stress in matrix at composite
permittivity (18.18) failure (16.5)
.
P s = steady-state creep rate (8.12) s T = true stress (6.7)
P T = true strain (6.7) s w = safe or working stress (6.12)
h = viscosity (12.10) s y = yield strength (6.6)
h = overvoltage (17.4) t = shear stress (6.2)
2u = Bragg diffraction angle (3.16) t c = fiber–matrix bond strength/
u D = Debye temperature (19.2) matrix shear yield strength
l = wavelength of electromagnetic (16.4)
radiation (3.16) t crss = critical resolved shear stress
m = magnetic permeability (20.2) (7.5)
m B = Bohr magneton (20.2) x m = magnetic susceptibility
m r = relative magnetic permeability (20.2)
(20.2)
m e = electron mobility (18.7) Subscripts
m h = hole mobility (18.10)
n = Poisson’s ratio (6.5) c = composite
n = frequency of electromagnetic cd = discontinuous fibrous
radiation (21.2) composite
r = density (3.5) cl = longitudinal direction (aligned
r = electrical resistivity (18.2) fibrous composite)
r t = radius of curvature at the tip of ct = transverse direction (aligned
a crack (8.5) fibrous composite)
s = engineering stress, tensile or f = final
compressive (6.2) f = at fracture
s = electrical conductivity (18.3) f = fiber
s* = longitudinal strength (compos- i = instantaneous
ite) (16.5) m = matrix
s c = critical stress for crack propa- m, max = maximum
gation (8.5) min = minimum
s fs = flexural strength (12.9) 0 = original
s m = maximum stress (8.5) 0 = at equilibrium
s m = mean stress (8.7) 0 = in a vacuum