Factor of Safety, N
Ultimate Strength / Working Strength
Mechanical Properties
Elastic Bulk Modulus
P = -K(ΔV/Vo)
K = E / 3(1-2v)
symbol, K
measure of the ability of a substance to withstand changes in volume when under compression on all sides
Elastic Shear Modulus
measure of the ability of a material to resist transverse deformations
τ = Gγ
G = E / 2(1+v)
Shear stress/shear strain
symbol, G
Resilience
the ability of a material to absorb energy when it is deformed elastically, and release that energy upon unloading.
Toughness
the strength with which the material opposes rupture
Ductilty
ability of a material to sustain a large permanent deformation
%EL = [(Lf – Lo) / Lo] x 100
%RA = [(Ao – Af) / Ao] x 100
Poisson's Ratio
Lateral Strain / Longitudinal Strain
ν = εL / ε
Permanent Deformation
Reversible Deformation
General Theory of
Stress and Strain
in Materials
Figure out new words by learning about the individual meanings of suffixes and prefixes.
Stress-Strain Curve
Plastic State
Fracture Point
Breaking Stress
Ultimate Yield Point
Ultimate Stress
Ultimate Yield Strength
Lower Yield Point
Elastic State
Elastic Yield Point
Yield Strength
unit, Pa, psi
Proportional Limit
Yonge's Modulus
or
Modulus of Elasticity
measures how aeasily a material streches or deforms
rise/run
E = Stress/Strain
symbol, E
unit, gPa
Hooke's Law
σ = E ε
Strain
Do you know what a 'prefix' is?
A prefix is an affix placed before a word, base, or another prefix to modify a term's meaning.
Shear Strain
sideways force exerted on a medium
Volumetric Strain
(ΔV/Vo)
Longitudinal Strain
ε = δ / Lo
Lateral Strain
εL = -δL / wo
unit, unitless
unit, Pa or psi
Stress
Do you know what a 'suffix' is?
A suffix is an affix placed at the end of the root word, which can change its tense and/or meaning.
Shear Stress
τ = Fs / Ao
Fs = shear force
Ao = original area (before loading)
Normal Stress
Tensile Stress
σ = Ft / Ao
Fs = tensile force
Ao = original area (before loading)
Compressive Stress
τ = F / Ao
F = compressive force
Ao = original area (before loading)
