Try out this code below:

print("Enter a negetive number to terminate the program ")
while True:
     factorial=1
     x=int(input("Enter the number "))
if x<0:
    print("Negetive number has no factorial\n Thanks for trying")
    break
elif x==0:
    print(x,"!=",1)
else: 
    for i in range(1,x+1):
        factorial=factorial*i
    print(x,"!=",factorial)

while True: in Python

While True, is a while loop that will loop forever as the evaluated condition is always met, always True.

Try this code below:

secret_code=521
while True:
x=int(input(“input a number= “))

if (x!=secret_code):
print (“This is not the right code”)
elif(x==secret_code):
print(“ok”)
break

Creep Analysis of T-joint

It is a common structure seen in ship. These structures remain under a high stress and temperature. If only static analysis is done for this kind of structures, they might look safe as the structures don’t cross the yield stress limit over the time. But creep analysis shows the time and locations of the presence of creep strain for the same working conditions. Where safety is the first priority creep analysis data are valuable to the engineers

See the full analysis PDF

Conclusion

Usually a ship consists of thousand tons of steel structures. These structures need to be designed precisely and built with materials of required properties. These structures normally work under different working conditions. As a result it is necessary to check whether it will be in a good service condition and safe during its lifetime. Creep behavior is an important criterion to be considered on this purpose.

Limitations

Pressure distribution over a propeller blade is normally non-uniform. But here for simplicity we assumed it as uniform. The intention of this analysis was to show a procedure and compare the results to show how it can be used in real cases and for more complicated blade shapes. These two blade designs were designed on AUTOCAD. So it will not be difficult to try for other designs and import to ABAQUS CAE for analysis.

Creep Analysis of Propeller Blades

Propulsion systems for surface ships and underwater vehicles have followed the standard propulsion mechanism for many years. Propellers have to be designed in a way to reduce noise and vibrations and hence cavitation to the lowest possible level in order to achieve propeller efficiency. To ensure the safety and durability of the propeller creep analysis of the design given the material properties is very important. Under a probable working condition the locations can be detected where stress concentration will occur by static analysis. Then creep analysis can show the probable locations where permanent deformation means creep can occur. Prediction of time after which the creep strain value crosses the danger limit is also an important one. Now it will be easier to take necessary precautions at the right time to avoid the initiation of crack propagation or sudden breakdown. The creep analysis will help a designer to modify his blade design considering other criteria to design the best one. For example two simple CAD designs of propeller blade are compared under same working conditions.

**Three bladed propeller designed in AutoCAD**

See the full analysis here PDF

Verification of Working Procedure

First we have to test the method ,we are working with , with experimental data before applying on ship structures.

Time dependent strain graphs are fitting into power equation in order to define the expression for uniaxial creep strain in terms of uniaxial stress σ , time t , and temperature T

The power law equation is modified to Bailey-Norton law in order to define the expression for unaxial creep strain in terms of unaxial stress , time and temperature

A sample creep test data was extracted for Grades of Stainless Steel –Grade 310

Stress to develop a creep rate of 1% at the indicated time at the indicated temperature

Then applied the stress and temperature for two separate time duration to see the results matching with the experimental data or not. We observed two analyses to see creep rate 1% is verified or not.

Read the full verification test here PDF

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Finding factorial of a number using while True in python