# Shared Flashcard Set

## Details

Intro to Mechanical Properties
N/A
53
Engineering
12/12/2015

Term
 The tensile force divided by the original cross-sectional area of a specimen is the engineering normal ____.
Definition
 stress
Term
 The change in length resulting from an applied force on a specimen divided by the original length is the engineering ___.
Definition
 strain
Term
 The negative of the ratio of the strain transverse to an applied force divided by the strain parallel to the applied force is equal to the ____ ratio.
Definition
 Poisson's
Term
 The tensile force divided by the actual cross-sectional area of a specimen is the ___ stress.
Definition
 true
Term
 If an applied stress is equal in three perpendicular directions, the stress is ___.
Definition
 hydrostatic.
Term
 A(n) ___ material has properties that are equal in three perpendicular directions.
Definition
 isotropic
Term
 In a tensile specimen with uniform strain, the true strain is equal to the natural log of 1 plus the ___.
Definition
 engineering strain
Term
 Recovered strain is ___ strain.
Definition
 elastic
Term
 Permanent strain is ___ strain.
Definition
 plastic
Term
 In an isotropic material subject to a hydrostatic stress, the volumetric strain is equal to ___ times the strain in the x direction.
Definition
 three
Term
 A shear strain causes changes in ___ in a specimen.
Definition
 angle
Term
 The linear relationship between stress and elastic strain is known as _____.
Definition
 Hooke's law
Term
 _____ is equal to the ratio of the applied stress to the elastic strain.
Definition
 Young's Modulus
Term
 In a nonlinear elastic material, the ratio of the applied stress to the total strain is the _____.
Definition
 secant modulus
Term
 In a nonlinear elastic material, the ratio of the increment in applied stress to the increment in strain measured at the total strain is the___.
Definition
 tangent modulus
Term
 The ratio of the hydrostatic stress to the elastic volumetric strain is equal to the ____.
Definition
 bulk modulus
Term
 A material that requires time to fully recover after the stress is reduced to 0 is ____.
Definition
 anelastic
Term
 In crystalline metals, plastic strain at low temperature is due to ____ motion.
Definition
 dislocation
Term
 In glass, plastic strain is due to the ____ and reformation of atomic bonds.
Definition
 breaking
Term
 In a crystalline metal at low temperature, the magnitude of the plastic strain is equal to the mobile dislocation density time the Burger's vector times the average ___ moved by the dislocations.
Definition
 distance
Term
 In the tensile test of single crystals, the proportional limit stress depends upon the angle of the slip plane and the slip ___ relative to the tensile axis.
Definition
 direction
Term
 In the tensile test of single crystals, the proportional limit stress is not constant; the ___ is constant
Definition
 critical resolved shear stress
Term
 The elastic modulus of a material, except for elastomers, is proportional to the ___ of the interatomic potential.
Definition
 curvature
Term
 The tensile stress where plastic strain begins is equal to the ____ limit.
Definition
 proportional
Term
 The tensile stress where plastic strain is equal to .002 is equal to the ___ stress.
Definition
 yield
Term
 The modulus of ___ is the maximum strain energy that a material can absorb and then fully return when unloaded.
Definition
 resilience
Term
 At the ultimate tensile strength, the slope of the engineering stress-strain diagram is equal to ___.
Definition
 zero
Term
 The area under the stress-strain curve to fracture a material is equal to the ___.
Definition
 toughness
Term
 The increase in specimen strength with plastic strain is ___ hardening.
Definition
 strain or work
Term
 The ratio of the change in the cross-sectional area at the location of fracture to the original cross-sectional area is equal to the ___.
Definition
 ductility
Term
 The logarithm of the ratio of initial cross-sectional area to the area at the location of fracture of a specimen is equal to the ___ to fracture.
Definition
 true strain
Term
 Thermosetting polymers are more brittle than thermoplastic polymers, because LCMs are ____.
Definition
Term
 For the low-carbon steel in Figure 6.16, at what strain would a neck start to form in the specimen?
Definition
 0.15
Term
 The tensile yield stress in ductile metals and polymers is approximately ___ of the compressive yield strength.
Definition
 100%
Term
 In crystalline metals and ceramics, elastic strain is due to the stretching or compression of _____ bonds resulting from changes in the lattice parameter.
Definition
 interatomic or chemical or atomic
Term
 The ___ strength of a brittle or composite material is the maximum tensile stress determined from a three-point bend test.
Definition
 flexural
Term
 Hardness is a measure of the resistance of a material to ___ by an indenter.
Definition
 penetration
Term
 During loading in a stress-strain test of a material, we observe that the plot is not linear and has no discontinuities. We can assume that:
Definition
 We CANNOT assume the material is nonlinear elastic, anelastic, or there is elastic and plastic strain.
Term
 Which of the following materials would you expect to have the lowest Young's modulus?
Definition
 Rubber
Term
 At the yield stress in a metal,
Definition
 the plastic strain is equal to .002.
Term
 Which of the following pure annealed materials would you expect to have the highest yield stress?
Definition
 HCP magnesium
Term
 Which of the following materials would you expect to be isotropic?
Definition
 a casting of aluminum
Term
 One reason that dislocation motion is difficult in covalently bonded materials such as diamond is that:
Definition
 Covalent bonds resist changes in angle.
Term
 Plastic strain in silica glass at a temperature just above the glass transition temperature is due to:
Definition
 The breaking and reforming of silicon-oxygen bonds with different neighbors.
Term
 What is the weight percent carbon in a 1040 steel?
Definition
 0.40%
Term
 Which of the following would not contribute to a high modulus of resilience?
Definition
 a high ductility
Term
 At the ultimate tensile strength,
Definition
 the maximum load-carrying capacity is experienced.
Term
 The toughness of a material is:
Definition
 the strain energy per unit volume needed to fracture the material.
Term
 The ratio of the tensile fracture strength of ceramics to the compressive fracture strength is typically:
Definition
 0.1 to 0.2
Term
 Which of the following tests would probably not be successful for a brittle ceramic material?
Definition
 Tensile test with a standard tensile-test specimen, as shown in Figure 6.15a.
Term
 If TiNi is deformed 5% at a temperature above the martensite start temperature, and then the strain is fully recovered upon reduction of the stress to 0, this material is ___.
Definition
 super or pseudo-elastic
Term
 If TiNi is deformed %5 at a temperature below the martensite finish temperature, and then the force is reduced to 0, how would you expect the material to respond?
Definition
 with a small elastic strain and a large plastic strain.
Term
 In the Brinell hardness test, the indenter is steel or tungsten, and the shape is a:
Definition
 sphere with a 10mm diameter
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