Chapter 11: Mechanical Properties

Example 11.1, page no-332

In [3]:
# Stress produced in an Al

import math
#Variable Declaration
ld=2000.0                        # Load applied
g=9.8                            # Acceleration due to gravity in m/s^2
r=0.005                          # radious of test piece

#Calculation
force=ld*g
stress= force/(math.pi*r**2)

#Result
print('The stress produce in an aluminium alloy is %.1f MPa'%(stress*10**-6))

The stress produce in an aluminium alloy is 249.6 MPa

Example 11.2, page no-332

In [6]:
# perentage elongation and reduction

import math
#Variable Declaration
lf=53.75*10**-3
l0=50*10**-3
df=9.4*10**-3
d0=8.8*10**-3

#Calculation
pl=(lf-l0)*100.0/l0
pa=((math.pi*df**2)-(math.pi*d0**2))*100.0/(math.pi*df**2)

#Result
print('\nThe %% elongation is %.1f%% and \nthe %% reduction in area is %.2f%%'%(pl,pa))

The % elongation is 7.5% and 
the % reduction in area is 12.36%

Example 11.3, page no-332

In [7]:
#Brinell Hardness Number

import math
#Variable Declaration
ts=937.0                # Tensile strength of steel


#Calculation
bhn=ts/3.45

#Result
print('The Brinell Hardness Number is %.2f'%bhn)

The Brinell Hardness Number is 271.59

Example 11.4, page no-333

In [12]:
#Tensile strength and fatigue limit of Steel plate

import math
#Variable Declaration
p=3000.0                         # Load applied
D=10.0                           # diameter of the indenter
d=2.2                            # diameter of the impression

#Calculation
Hb=2*p/(math.pi*D*(D-math.sqrt(D**2-d**2)))
Hb= math.floor(Hb*10)/10
ts=3.45*Hb
fl=0.5*ts

#Result
print('\nBrinell Hardness Number of steel Plate, Hb=%.1f\n'%Hb)
print('\nThe Tensile strength of steel plate is %.3f MPa\n'%ts)
print('\nThe Fatigue limit of steel plate is %.4f MPa'%fl)

Brinell Hardness Number of steel Plate, Hb=779.5


The Tensile strength of steel plate is 2689.275 MPa


The Fatigue limit of steel plate is 1344.6375 MPa