Question Set 40 – Mechanical Engineering

# Question Set 40

Question No.1

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

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

The relation is, Kf = 1 + (Kt-1)

Question No.2

What are the factors that affect notch sensitivity?

The factors effecting notch sensitivity are:

1.     Material

3.     Size of component

5.     Grain Structure

Question No.3

What is the use of Goodman & Soderberg diagrams?

They are used to solve the problems of variable stresses.

Question No.4

Define machinability

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?

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?

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

Question No.7

Give some example for curved beam.

C frame, crane hook

Question No.8

What is principle stress and principle plane?

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.

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.

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)