MSE2001 Exam 1 Terms

Material Property

An intrinsic property of a material that DOES NOT depend upon size or shape

Performance Parameter

The property of a component that is determined by size, shape, and material properties.

Important factors that properties of a material depend upon.

Microstructure, defects, internal strain, crystal

Tensile Test

a test that measures the stress-strain curve for a material.

What mechanical property does the red line demonstrate?

Elastic Regime

Elastic Regime

stretching of atomic bonds; the material will return back to its orginal shape

Elastic Deformation

a deformation that is reversible

Hooke’s Law

a linear relationship between stress and strain; stress = E * strain

What does E represent in Hooke’s Law

the slope of the linear portion of the stress-strain curve; stiffness

What mechanical property does the red line demonstrate?

Plastic Regime

Plasticity

any change in shape that does not revert back to the original

What mechanical property does the green line demonstrate?

Yield Stress

Yield Stress

the stress required to permanently deform the material

What mechanical property does the blue circle demonstrate?

Ultimate Tensile Strength

Ultimate Tensile Strength (UTS)

The stress beyond which the material fails/ fractures.

What mechanical property does the blue circle demonstrate?

Fracture Strain / Ductility

Ductility

the maximum amount of strain at failure

Poisson Ratio

Strain in one direction will cause a shrink in the other.

What mechanical property does the shaded area depict?

Toughness

Toughness

how much energy it requires to break the material (integration under the curve).

What mechanical property does the shaded area depict

Resilience

Resilience

how much energy it requires to permanently deform the material (integration under the elastic regime).

Stiffness

How much force (stress) does it take to flex the material

Elastic Modulus (Stiffness)

The material’s mechanical resistance to stretching, bending, or flexing.

Strength

How much force does it take to permanently deform the material.

Hardness

describes how difficult it is to scratch a material; approximately related to yield strength.

Sound

Sound is transmitted through materials as longitudinal strain waves.

What formula does this represent.

velocity of sound in a material

Sound travels best through materials with what properties?

High Stiffness, Light Weight/Density

What does this formula represent?

Acoustic Impedance

Acoustic Impendance

Determines how much of the sound is transmitted or reflected.

Large Z mismatch

acoustic reflection; most sound is reflected at interface

Small Z mismatch

acoustic transmission; most sound is transmitted into 2nd material