Page 392 - Engineered Interfaces in Fiber Reinforced Composites

Symbols and abbreviations 313

CTE of matrix
volume ratio of fiber to matrix (= a2/(b2 - a2))
displacement
6, residual displacement
E (tensile) strain (q fiber; E, matrix; E, composite)
AE differential strain between fiber and matrix
r gamma function
surface free energy
I
Ysv surface free energy at the solid-vapor interface
YLV surface free energy at the liquid-vapor interface
surface free energy at the solid-liquid interface
1’SL
Yd surface free energy due to dispersion forces
YP surface free energy due to polar contribution
9 viscosity of fluid
o inclined angle of fiber to the applied stress direction
contact angle (Or: change in contact angle due to rough surface)
r. reciprocal length giving effective shear stress transfer
11 coefficient of friction
11 shear modulus
Pc effective in-plane shear modulus
1’ Poisson ratio (vf fiber; v, matrix; v, composite; vi interlayer or
coating)
vo velocity of fiber pull-out
% spreading pressure
P density
(T longitudinal stress or strength
asymptotic debond stress
frictionless initial debond stress
residual stress at the fiber-coating interface in the radial direction
interface bond strength in tension
composite strength
residual stress at the coating-matrix interface in the radial direction
debond stress
partial debond stress
maximum debond stress
fiber axial stress
fiber tensile strength
matrix axial stress or tensile strength
matrix yield strength
net compressive stress
external stress for interfacial debonding
external stress for fiber fragmentation
initial frictional pull-out stress
fiber tensile strength at critical transfer length
crack tip debond stress