FEA Analysis on Pressure Vessel Using Patran/Nastran

[110303]

Hello My Friends,

Anyone has any experiences using Patran/Nastran (MSC Software) to analyze a pressure vessel under a 20g shock test? If you do, please let me so that I could ask you some specific questions.

Thanks a lot for your time and help.

Regards,

 

[CESSNA1]

110303: Many years ago I sued NASTRAN to do shock analysis on ships. Don't know I I can help but let's try

Regards
Dave

http://www.wsec1.com

 

[rb1957]

Nastran NL ? ... the key to the problem is how quickly does the pressure vessel stop. After 18" it'll be falling at about 10 ft/sec. if it stops instantly, the g's are infinite; if it stops (deaccelerating linearly) in roughly 0.06sec, it'll experience 20g

 

[110303]

Thanks rb1957. How did you get 20g with the given time of 0.06 sec. I got 10 / 0.06 = 167 ft/sec2, which I believe is 5.2g. Where did I do wrong?

Thanks a lot for your help.

 

[rb1957]

duh, 1/64 is not equal to 1/16 (0.06) !!!

20g = 640 ft/sec2

t = v/a = 10/640 = 1/64 = 0.015

BUT remember this is constant deceleration, which may be conservative, and who knows how long the original test took ? (so how do you justify the number ?) the best answer to this i think is what is general practice.

good luck

 

[110303]

Thanks rb1957 for your help. I will use this analysis for now before I do the FEA analysis.

Regards

 

[Drej]

I'm sorry, but I have to say this. There is no such thing as a Finite Element Analysis Analysis (FEA Analysis). There is, however, such a thing as an FE Analysis or just FEA.


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[110303]

You are correct. My mistake.