Question Set 40

Question No.1

Explain notch sensitivity. State the relation between stress concentration factor and notch sensitivity.

Answer:

Notch sensitivity (q) is the degree to which the theoretical effect of stress concentration is actually reached.

The relation is, Kf = 1 + q (Kt-1)

Question No.2

What are the factors that affect notch sensitivity?

Answer:

The factors effecting notch sensitivity are:

1.     Material

2.     Notch radius

3.     Size of component

4.     Type of loading

5.     Grain Structure

Question No.3

What is the use of Goodman & Soderberg diagrams?

Answer:

They are used to solve the problems of variable stresses.

Question No.4

Define machinability

Answer:

It is the property of the material, which refers to a relative ease with which a material can be cut. It is measured in a number of ways such as comparing the tool life for cutting different material

Question No.5

What is an S-N Curve?

Answer:

An S- N curve has fatigue stress on ‘Y’ axis and number of loading cycles in ‘X’ axis. It is used to find the fatigue stress value corresponding to a given number of cycles.

Question No.6

What is curved beam?

Answer:

In curved beam the neutral axis does not coincide with the centroidal axis.

Question No.7

Give some example for curved beam.

Answer:

C frame, crane hook

Question No.8

What is principle stress and principle plane?

Answer:

A plane which has no shear stress is called principle plane the corresponding stress is called principle stress.

Question No.9

Write the bending equation.

Answer:

The bending moment equation is, M/I = f/y= E/R,

Where,

M – Bending moment (M is in N-mm)

I - Moment of inertia about centroidal axis (I is in mm⁴)

f – Bending Stress (f is in N/mm²)

y - Distance from neutral axis (y is in mm)

E - Young’s modulus (E is in N/mm²)

R - Radius of curvature (R is in mm)

Question No.10

Write the torsion equation.

Answer:

The torsional equation is, T/J = q/r = GӨ/L

Where,

T – Torsional moment (T is in N-mm)

J - Polar moment of inertia (J is in mm⁴)

q – Shear stress in the element (q is in N/mm²)

r - Distance of element from centre of shaft (r is in mm)

G- Modulus of Rigidity (G is in N/mm²)

Ө – Angle of twist (Ө is in radians)

L – Length of the shaft (L is in mm)