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Unformatted text preview: per unit area associated with
in one portion of the crystal, a tilt is created.
internal or external surfaces. It has units of energy/area,
which is equivalent to force/length.
time-dependent deformation Deformation that occurs
syndiotactic Conﬁguration of a vinyl polymer × 105
as a function of time, independent of whether such
Number of cycles
established during polymerization corresponding to side
deformation is elastic or plastic.
FIGURE 14.5–8 Normalized elastic modulus as a function of fatigue cyclesthe glass ﬁber–polymer matrix comin a backbone.
groups positioned on alternating sides of
transference numbers A set of values ranging from 0
posite. (Source: K. K. Chawla, Composites Material Science and Engineering, 1987, Springer-Verlag, New York.
temperature coefﬁcient York resistivity The materials
to 1 that describe the relative contributions of anions,
Reprinted with permission of Springer-Verlag, New
property that describes the magnitude of the change in
cations, electrons, and holes in the transport of electrical
the resistivity of a conductor resulting from a change in
charge through a solid.
true strain t The natural logarithm of the
tempered martensite The result of heat-treating a
instantaneous length divided by the original length.
microstructure containing martensite. Tempered
Numerically, it is essentially equivalent to the
martensite consists of a ﬁne dispersion of Fe3C particles
engineering strain for strains up to about 0.1.
in an -ferrite matrix. The ductility and toughness of a
true stress t The force divided by the instantaneous
martensitic microstructure are enhanced by tempering.
area normal to the applied force.
temporary dipole An atom or molecule in which the
twin A portion of a crystal in which all of the atoms
spatial center of positive charge is momentarily different
are in mirror-image positions compared with atoms in
from the center of negative charge.
the bulk of the crystal.
tetrahedral 0site 10 A 102 103 in a crystal 106 107 by four
position 104 105 deﬁned
twist boundary A boundary that is composed of a
Number of cycles, N
grid of screw dislocations of like sign on the same plane.
FIGURE 14.5–9 Number of fatigue cycles required to achieve different fractions of stiffness reduction as a function
thermal capacitance The extrinsic counterpart of
of applied maximum fatigue stress. (Source: K. K. Chawla, Composites Material Science and Engineering, 1987, As a result of the displacements around the grid, a twist
speciﬁc heat obtained by multiplying speciﬁc heat by
Springer-Verlag, New York. Reprinted with permission of Springer-Verlag, New York Publishers.) the
mass of the object under investigation.
ultimate tensile strength uts The maximum value of
fails. The elastic modulus of the composite decreases continuously as fatigue damage
thermal conductivity The constant of proportionality
accumulates and is frequently used as an...
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