Mechanical Properties of Metals - Chapter 8 Flashcards Preview

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Flashcards in Mechanical Properties of Metals - Chapter 8 Deck (15):
1

Engineering stress

= F/Ao

2

Engineering Strain

= Delta[L]/Lo

3

Shear stress

= F/Ao

4

E-modulus

stress/strain

5

Anelasticity

Time-dependent elastic strain component -> elastic deformation will continue after the stress application, and upon load release, some finite time is required for complete recovery.

6

Poisson's ratio

v= Lateral strain/axial strain

7

Relation between shear and elastic moduli?

E = 2G (1 + v)

8

Yielding

The point of yielding may be determined as the initial departure form linearity of the stress-strain curve; this is sometimes called the proportional limit. The strain offset is usually 0.002

9

Ductility

It is a measure of the degree of plastic deformation that has been sustained at fracture.

10

Percentage elongation (%EL)

%EL = [(Lf-Lo)/Lo] x 100

11

Percent reduction in area (%RA)

%RA = [(Ao-Af)/Ao] x 100

12

Resilience

Resilience is the capacity of a material to absorb energy when it is deformed elastically and upon unloading, to have this energy recovered.

13

Modulus of Resilience (Ur)

Ur = Integration[stress d(strain)]

Assuming a linear elastic region:

Ur = 1/2 (stress)(strain)

Also,

Ur = Stress^2/2E

14

Toughness

indicates a material's resistance to fracture when a crack is present.

Also indicates the ability of a material to absorb energy and plastically deform before fracturing.

15

Hardness

Hardness is a measure of a material's resistance to localized plastic deformation.