hi everyone,

can anybody please explain me what are the considerations to be taken in the analysis of piping in hull systems. science the piping in hull systems subject to deformation of hull and weight of topsides, in CAESAR tell me how to apply this deformation on to piping inside hull system .

so please tell me how to perform above analysis in CAESAR.

Regards
B.Suresh kumar

Do you really mean sub sea ? Is it a submarine ?

Assuming it's a floating structure, you need to consider in addition to the usual sustained and thermal loads on piping, imposed displacments, accelerations the resulting loads and fatigue aspects. Inadaquately engineered piping on a floating structure, whether topsides or hull, may suffer fatigue failure very quickly. It's been said before ... Get some help from an expert.

Thanks moverz


can u please tell where do we get imposed displacments & acclerations and how to apply these in ceasar. and also please tell me how to define load cases in caesar for imposed displacements & accs.


Regards
B.Suresh kumar

Oh come on!!!!!!!!!!!!!!!!!!
For god sake!

its Easy.

1. Find yellow pages
2. Look up Marine stress analysis experts.
3. Put work in envelope
4. Post to said experts
5. Post Payment and recieve analysis.
6. Tell your boss how good you are.


I swear, we'll kill somebody one day

Its about time the shield of anonymity for posting in this forum be removed. So there should be more direct responsibility on to the user and indirectly to the employer when using this forum.

I understand this can be quite a debate but rather getting to the frustration point its better to put some restriction or exercise good control over the situation. As far as I see if I have to take the responsibility of my posts in reality, better I would think 100 times before asking naive question anonymously and do my homework in first place.

Company policies/ human rights/ identity verification/ additional costs of doing this etc etc may hinder this thing but this is what I think personally. Hope moderators would take this suggestion on board for consideration!

B.Suresh kumar,

On the semi-submersibles that I've worked on the hull displacement data came from the Navel Architect.

You don’t' say much about your system, but the information you need and how you use it will vary dramatically depending on the vessel type and where your system is located in the hull.

You may need to do fatigue analysis considering hull deflections due to current directions and sea states.

Having been employed in this industry during the era of punch cards I will state that Mr. Kamar needs help on a scale other than through a simple internet forum and personally I hope he can forgo his pride and sekk it out.

there are no stupid questions, only stupid answers.

I have asked plenty of very uneducated questions on this forum, its part of the learning process and the sharing of knowledge is half the fun.

Mr B's question in itself is not the problem, rather his willingness to approach such important work with such little (percieved) knowledge.
I suspect he does'nt appreciate what it is he is trying to achieve, or the potential for disaster if he does something wrong.

I honestly could not ask that level of question, knowing full well i have not done floating platforms before.
(i havent done them, and would only tackle same under the close guidence of a experienced collegue)

I would'nt have the neck.

I'm still in shock.

If there is one complaint I would press against Caesar and its competitors, it is the apparent simplicity of creating an input and getting out a load of numbers. Mr Suresh Kumar's question and response epitomises the danger of a such a clever tool in dangerous, cavalier hands.
Sitting in front of a PC in a nice office may seem a long way from struggling to a lifeboat on a sinking FPSO. A fatal accident enquiry may not agree.

Ref. Mr Luf's comments, I have also been around since that era. Punch cards, strictly fielded 80 char. input forms and unitelligable output from the likes of 1970's ADLPIPE di at least put off the chancers, as did the frightening cost per run.

No offence intended to Rich Ay and Tony Paulin, the upsides of Caesar hugely outweigh the (IMHO) downsides.

how about this on the front screen........



WARNING:

INCORRECT ANALYSIS CAN LEAD TO LOSS OF LIFE AND PROPERTY
.................PROCEED WITH CAUTION...................
.....................COADE Inc..........................

Well said MoverZ my compliments....

Superpiper unlikely it would be the only software in the market to so boldly state this and as such would suffer unfairly from it!

It was a joke
(I think)

I liked the idea but it is impractical commercially speaking. I believe there is a warning statement somewhere in the documentation that nobody reads anyhow!

Luf-Sir is right. It is impractical & useless.

Such a trend will reverse; le us just wait & watch & not be one in fuelling such a destructive trend for our own profit. If monkey kills,we must find the man who give the monkey a gun & why?

regards,

sam

Here's a quote from the Forward of ASME Section VIII Division 1:
"The Committee recognizes that tools and techniques used for design and analysis change as technology progresses and expects engineers to use good judgement in the application of these tools. The designer is responsible for complying with Code rules and demonstrating compliance with Code equations when such equations are mandatory. The Code neither requires nor prohibits the use of computers for the design or analysis of components constructed to the requirements of the Code. However, designers and engineers using computer programs for design or analysis are cautioned that they are responsible for all technical assumptions inherent in the programs they use and they are responsible for the application of these programs to their design."

So there you have it. Now, this is not a piping code but it is a pressure vessel code - we're in the same business trying to keep high energy systems safe.

Here's how I see things:

There are three components to a computer analysis: 1)Concept, 2)Program Input, & 3)Program Results. The designer/engineer uses Concept and creates Input and the software vendor uses Input and creates Results. Of course we make mistakes on the vendor side, that's why we issue Builds. But where do you think the majority of problems occur? It's between Concept and Input. And, yes, making input easier makes it easier to produce bad numbers.

A parallel discussion can be had on the status of the piping Codes - they are currently focused on slide rule calculation. B31.3 is slowly pulling in current analysis techniques (e.g. Appendices P & S) but I wonder when this tectonic shift between existing Code rules and advancing analytical technology will quake the earth.

A final thought: The purchase of CAESAR II provides a tool. A purchase of CAESAR II is not a purchase of knowledge. But now I think I'm preaching to the choir...

Amen, Brother!!!!!!!!!!

HI

Thanks for replies

I am working in power piping stress analysis. In our company we also handle hull systems but the analysis of piping in hull system is taken care by our experienced employees. I am no where involved in this hull system piping analysis. I have very less knowledge in hull systems piping and I am very curies to know about pipe stress analysis of hull systems. I know what are the Consequences of wrongly done analysis.
I am asking to you (experience persons) to provide guidance so that I can improve my knowledge, that’s all

Warning: Coffee is hot! McDonald's Inc.

Maybe Rich or Dave will disagree with me on this, but I think these warnings are absurd. It is not the tool that hurts, but incorrect application of it (whether intentional or unintentional), and that is definitely not the toolmaker's responsibility.

Having said that, we try to elucidate our customers to the best of our ability on proper application of all our software, which is why we have this forum and technical support and newsletters and seminars.

If you want to learn how to design and analyze shipboard piping, it appears you have experts available in your company. My guess is that they would be happy to discuss the basics with you if you ask them properly and show some interest as the discussion progresses.