MIE 302 Quiz

Hardness is a measure of a material's

Resistance to indentation

The Rockwell hardness number (on any scale) is

None of the above

The Rockwell C test - used, for example, on hardened steels - employs a

Diamond (brale) indenter

Typically, the tensile strength of a material and its hardness are

Directly proportional

Means of normally-distributed populations (of unknown variance) evaluated using small sample

sizes follow a

t-distribution

Using the crosshead displacement to calculate specimen strain is less reliable than using the

extensometer reading because

The accuracy of the crosshead reading is compromised by machine compliance

Tensile-testing specimens are machined to have a dog-bone shape because

This increases the stress and thus localizes failure within the reduced (gauge) section

With reference to Fig. 1, a reasonable estimate

of the yield stress is obtained by

reporting the minimum (or average) value

of stress across the Lüders region (B)

(Fill in the blank) The load cell of a universal testing machine measures the applied

to the specimen.

Force

In today's experiment, you will test only one sample of a given material and thus report only a

single value for the ultimate tensile strength of the material. The uncertainty in the tensile strength

will be quantified by applying

The method of error propagation

The Griffith criterion pertains to

Fracture in brittle materials

The probability that a brittle solid of volume V survives a tensile stress σ is given by the expression

Ps(V) = exp [-(σ/σ0)

m]. The parameter m in this formula is called the

Weibull modulus

Typically, the tensile strength of a (single-phase) material and its fracture toughness are

Inversely proportional

(Fill in the blank) On average—i.e., statistically—scaling up (increasing) the size of a ceramic

component leads to _______________ in its failure strength.

a decrease

With reference to the four-point bend test setup in Figure 1, which of the following statements is

correct?

The bending moment in segment BC is constant

Ductile-to-brittle transitions are typically displayed by

Low-strength steels

The impact energy vs. temperature plots for a low

carbon steel (BCC) and stainless steel (FCC) are

shown schematically in Fig. 1. Which material

matches which curve?

Stainless Steel (Striaght)

Low-Carbon Steel (Curved)

Increasing the carbon content of a BCC steel will

lower the fracture toughness and raise the ductile-to-brittle transition temperature

Precision resistance measurements are generally made using a

Wheatstone bridge

The gauge factor is a constant of proportionality that relates

the relative change in gauge resistance ΔRg/ Rg to the applied strain ε

Determining the complete two-dimensional (in-plane) state of strain at a point on a surface requires

at minimum ______ strain measurements along independent (non-collinear) directions at that point.

3

Which of the following materials is commonly used in a strain gauge?

Constantan