Chemistry Reference
In-Depth Information
(a) TENSILE DEFORMATION
(b) SHEAR DEFORMATION
CROSS-
SECTIONAL
AREA A
TOP FACE
HAS AREA A
f
α
l
o
l
f
TENSILE
STRAIN:
SHEAR
STRAIN:
SHEAR
STRESS:
ε =
(l - l
o
)/ l
o
γ =
tan
α
TENSILE
STRESS:
σ
=
f/A
λ =
f/A
SHEAR
MODULUS:
TENSILE
MODULUS:
G
= λ /γ
Y
=
σ/
ε
TENSILE
COMPLIANCE:
SHEAR
COMPLIANCE:
D
= ε/λ
J
= λ/
σ
(c) BULK COMPRESSION
BULK MODULUS = PV/∆ V
=
K
BULK COMPLIANCE = L/K
=
B
PRESSURE = -P
FIGURE 4.14
(a) Elastic constants in tensile deformation. (b) Elastic constants in shear deformation. (c)
Elastic constants in volume deformation.
permanent deformation in solid polymers while rapid shearing will induce elastic
behavior in some macromolecular liquids. It is also frequently observed that the
value of a measured modulus or viscosity is time dependent and reflects the man-
ner in which the measuring experiment was performed. These phenomena are
examples of
viscoelastic
behavior.
