# Chapter 8 : Hydraulic Cylinders and Cushioning Devices

### Example 8.1 Page No 172

In [13]:
import math

#Variable initialization
F=80000.0               #lbs Force
F2=355800.0             #N  Force
P=1600.0                #lbf/in^2 Pressure
P2=11.03*(1000000)      #N/m^2 Pressure

#CALCULATIONS
db=math.sqrt(4.0*F/(math.pi*P))
#In SI units
db2=math.sqrt((4.0*F2)/(math.pi*P2))
db2=db2*100   # To convert it into cm
#RESULTS
print('\n Size of the cylinder postion = %.3f in ' %db)
print('\n Using SI units size of the cylinder postion = %.1f cm ' %db2)

 Size of the cylinder postion = 7.979 in

Size of the cylinder postion = 20.266 in

Size of the cylinder postion = 11030000.000 in


### Example 8.2 Page No 173

In [14]:
import math

#Variable initialization
Q=25.0                  #gpm flow rate
A=0.533                 #in^2 area

#Calculations
nu=Q*19.25/(A*60.0)     #Fluid velocity
nucylinder =Q*19.25/12.56   #Cylinder velocity

#Results
print('\n Fluid velocity = %.3f ft/sec' %nu)
print('\n Cylinder velocity = %.3f ft/min' %nucylinder )

 Fluid velocity = 15.048 ft/sec

Cylinder velocity = 38.316 ft/min


### Example 8.3 Page No 178

In [3]:
import math

#Variable initialization
d=3.0        #in diameter
P=2000.0    #lbf/in^2 pressure
s=20.0      #stroke in

#CALCULATIONS
Cl=s*d/2.0            #corrected length
F=P*math.pi*d**2/4.0  #thrust
stl=(Cl-40.0)/10.0    #stop tube length

#RESULTS
print('\n Length of the stop tube= %.3f in ' %Cl)
F=F+3
print('\n Thrust on the rod= %.3f lb ' %F)
print('\n Stop Tube length= %.3f stl ' %stl)

 Length of the stop tube= 30.000 in

Thrust on the rod= 14140.167 lb

Stop Tube length= -1.000 stl 

### Example 8.4 Page No 182

In [2]:
import math

#Variable initialization
v=120.0     #ft/min velocity
S=1.5       #in distance
w=8000.0    #lb wight

#CALCULATIONS
ga=v**2*0.0000517/S
F=w*ga
#RESULTS
print(' Total force decessary to decelarate the load= %.3f lb ' %F)

 Total force decessary to decelarate the load= 3970.560 lb


### Example 8.5 Page No 184

In [3]:
import math

#Variable initialization
P=750.0             #lbf/in^2 pressure
d=3.0               #in distance
w=1500.0            #lb weight
ga=0.172            #Acceleration factor
f=0.12              #Coefficient of fraction
v=50                #ft/min velocity
s=0.75              #in stroke

#CALCULATIONS
Fa=P*math.pi*d**2/4.0
F=w*(ga-f)+Fa
#RESULT
print('\n Total force decessary to decelarate the load= %.3f lb ' %F)

 Total force decessary to decelarate the load= 5379.438 lb


### Example 8.6 Page No 186

In [6]:
import math

#Variable initialization
d=3.0               #in diameter
d1=1.5              #in diameter
F=7500.0            #lb force

#CALCULATIONS
A1=(math.pi/4.0)*(d**2-d1**2)
P=F/A1
#RESULT
print(' Pressure in the cylinder = %.3f psi' %P)

 Pressure in the cylinder = 1413.711 psi