Definitions /Dictionary/Glossary - nptel

Modulus, Tangent: The ratio of change in stress to change in strain derived from the tangent to
any point on a stress-strain curve.
Modulus, Young's: The ratio of change in stress to change in strain below the elastic limit of a
material (Applicable to tension and compression).
Modulus of Resilience: The energy that can be absorbed per unit volume without creating a
permanent distortion.
Modulus of Rigidity (also Shear Modulus or Torsional Modulus): The ratio of stress to strain
below the proportional limit for shear or torsional stress.
Modulus of Rupture, in Bending: The maximum tensile or compressive stress (whichever
causes failure) value in the extreme fiber of a beam loaded to failure in bending. The value is
computed from the flexure equation:
F
M
=
I
b c
where,
M = maximum bending moment computed from the maximum load and the original moment
arm,
c = initial distance from the neutral axis to the extreme fiber where failure occurs,
I = the initial moment of inertia of the cross section about its neutral axis.
Modulus of Rupture, in Torsion: The maximum shear stress in the extreme fiber of a member
of circular cross section loaded to failure in torsion calculated from the equation:
F
T
=
J
s r
where,
T = maximum twisting moment,
r = original outer radius,
J = polar moment of inertia of the original cross section.
Moisture Absorption: The pick-up of water vapor from air by a material. It relates only to
vapor withdrawn from the air by a material and must be distinguished from water absorption,
which is the gain in weight due to the take up of water by immersion.
Moisture Content: The amount of moisture in a material determined under prescribed condition
and expressed as a percentage of the mass of the moist specimen, i.e., the mass of the dry
substance plus the moisture present.