MSE 220 MIDTERM 2 QUESTIONS WITH VERIFIED
ANSWERS
Mechanical properties are usually measured by - Answers - destructive test
modulus of elasticity is a ____ property - Answers - mechanical
stress - Answers - force distributed over an area
sigma = F/A
elastic deformation - Answers - structure returns to its original shape on removal of load
plastic deformation - Answers - load causes permanent deformation
strength - Answers - a materials ability to accommodate stress
types of strength/stress - Answers - -tensile
-torsional
-shear
-compressive
-creep
-stress rupture
-flexural
the tensile test - Answers - laboratory technique for determining a number of important
material properties:
-tensile strength
-yield strength
-modulus of elasticity
-%reduction in area
-%elongation
with different techniques the same machine can be used for:
-compressive strength
-shear strength
-flexural strength
materials that exhibit a linear stress-strain curve in the elastic range are said to be... -
Answers - Hookean
modulus of elasticity - Answers - slope of the linear portion of the stress-strain curve,
calculated by delta(stress)/delta(strain)
, elastic limit, or yield point - Answers - point of deformation of a material from elastic to
plastic
engineering yield point - Answers - yield point but at a 0.2% strain offset
many testing standards and published handbook data designate the stress at 0.2%
offset strain as the yield stress
ultimate tensile stress point - Answers - where the reduction in cross-sectional area
occurs in a localized spot in the test sample, known as necking
ductility - Answers - a measure of a material's ability to be stretched or drawn, typically
reported as precent elongation or percent reduction in area
strain hardening - Answers - when a metal is plastically deformed, interactions with
dislocations in the material's structure can cause it to harden and become stronger
also known as work hardening
toughness - Answers - The ability of a material to absorb energy before fracturing.
The amount of energy required to fracture a given volume of material.
(impact resistance)
It is the area under the stress-strain curve up to the point of fracture.
Huber Von Mises-Henkey
distortion energy theory for ductile material
failure - Answers - Shear strength ~ 57.7% of the tensile strength
shear stress-strain relationship - Answers - σs=Gεs
shear stress = shear modulus * shear strain
Harness - Answers - wear resistance and durability
in steels, it serves as a measure of abrasion and strength
Hardness testing - Answers - Tested for hardness by filing an
edge.
The hardness of ceramics and minerals was
and still, is measured by scratching the surface
with different types of minerals, called
the Mohs hardness test.
Most present-day hardness tests consist of
pushing a penetrator into the material and
measuring the effects.
Brinell Hardness Test - Answers - A 10-mm diameter ball is pushed into the surface,
and an optical measuring device is used to measure the diameter of the resulting
indentation. This diameter is then used to calculate a Brinell hardness number (HB).
ANSWERS
Mechanical properties are usually measured by - Answers - destructive test
modulus of elasticity is a ____ property - Answers - mechanical
stress - Answers - force distributed over an area
sigma = F/A
elastic deformation - Answers - structure returns to its original shape on removal of load
plastic deformation - Answers - load causes permanent deformation
strength - Answers - a materials ability to accommodate stress
types of strength/stress - Answers - -tensile
-torsional
-shear
-compressive
-creep
-stress rupture
-flexural
the tensile test - Answers - laboratory technique for determining a number of important
material properties:
-tensile strength
-yield strength
-modulus of elasticity
-%reduction in area
-%elongation
with different techniques the same machine can be used for:
-compressive strength
-shear strength
-flexural strength
materials that exhibit a linear stress-strain curve in the elastic range are said to be... -
Answers - Hookean
modulus of elasticity - Answers - slope of the linear portion of the stress-strain curve,
calculated by delta(stress)/delta(strain)
, elastic limit, or yield point - Answers - point of deformation of a material from elastic to
plastic
engineering yield point - Answers - yield point but at a 0.2% strain offset
many testing standards and published handbook data designate the stress at 0.2%
offset strain as the yield stress
ultimate tensile stress point - Answers - where the reduction in cross-sectional area
occurs in a localized spot in the test sample, known as necking
ductility - Answers - a measure of a material's ability to be stretched or drawn, typically
reported as precent elongation or percent reduction in area
strain hardening - Answers - when a metal is plastically deformed, interactions with
dislocations in the material's structure can cause it to harden and become stronger
also known as work hardening
toughness - Answers - The ability of a material to absorb energy before fracturing.
The amount of energy required to fracture a given volume of material.
(impact resistance)
It is the area under the stress-strain curve up to the point of fracture.
Huber Von Mises-Henkey
distortion energy theory for ductile material
failure - Answers - Shear strength ~ 57.7% of the tensile strength
shear stress-strain relationship - Answers - σs=Gεs
shear stress = shear modulus * shear strain
Harness - Answers - wear resistance and durability
in steels, it serves as a measure of abrasion and strength
Hardness testing - Answers - Tested for hardness by filing an
edge.
The hardness of ceramics and minerals was
and still, is measured by scratching the surface
with different types of minerals, called
the Mohs hardness test.
Most present-day hardness tests consist of
pushing a penetrator into the material and
measuring the effects.
Brinell Hardness Test - Answers - A 10-mm diameter ball is pushed into the surface,
and an optical measuring device is used to measure the diameter of the resulting
indentation. This diameter is then used to calculate a Brinell hardness number (HB).
