Hello,
Can anybody guide me that which code is applicable for high pressure (2000 bar) hydraulic tubing. i want to do stress analysis can i do it on caesar II?
thanx and best regards!

Chapter IX of ASME B31.3 deals with piping in excess of PN420 (2500#) flange rating and has no defined upper limit, so should be relevant to your tubing. I don't see why there should be any problems using Caesar II for stress analysis of this sort of pipe.

This is a tough issue. First of all, it's likely that your tubing fittings are not "qualified components" under the B31 Codes. Second, the fatigue loads that are applied to hydraulic and pneumatic power systems are a result of pressure cycles and fluid acceleration and deceleration forces. Most such piping systems see only minor temperature variations during their usual operating cycles.

All this leads to the conclusion that the B31 Codes are not terribly well suited to the analysis of such piping. Neither B31.1 nor B31.3 claim jusisdiction over such piping; B31.1 specifically excludes the drops from the headers to the tools or machines in 100.1.3 (C).

nothing else is better, though. For detailed analysis of a small portion of the system, FEA would be a good tool, but it's clearly not warranted for a whole piping system. And the enclosed volume would be way to small to fall under the jurisdiction of the BPVC, even if you tried to include it. There are other Codes that apply to hydraulic piping systems. You might want to read this for further enlightenment (?).

http://www.wbdg.org/ccb/DOD/UFGS/UFGS%2041%2024%2026.pdf

I would strongly argue that the wall thickness calculations should be done under the rules of B31.3 and after that it's up to the designer. If you are concerned with the margin of safety on wall thickness, you may want to model the system and apply the pressure cycle and fluid transient load cycle to the system. You will then have to go back and do a hand calculation using the methodology of 302.3.5 to determine the "equivalent number of cycles" for the piping system. You could use this to make a good guess at the minimum fatigue life to expect for the system, but it would be little more than that; a statement of the 95% confidence level of the fatigue life of the system. That's pretty good, but one man's 95% confidence level is another man's guess.

Kazi,

I think the beginning of an answer to this question is to try and define an application standard (i.e. the best code for the application). There are a number of standards that cover general fluid power applications, automotive applications, machinery applications, etc and that's before you find out whether there are any particular requirements for the equipment in its country of use.

If possible, can you give more information on this system, where it is to be used and why you think CAESAR II would be a useful tool here.

Dear Stan Mckay,
I already asked in my question that i have to design a hydraulic tubing system at a pressure of 2000bar. i think this is enough to specify an application standard. but to add more on this that the hydraulic system is for a press unit.I studied Chapter IX of ASME B31.3 deals with highr pressure piping in excess of PN420 (2500#) flange rating and has no defined upper limit,but Craig B Arguement is right that have to consider fatigue loads and pressure cycles.

But if i have to ruled out the use of CAESER II than which Code or standard should i use specifically for the design.I think there are code or standard availble ,so please guide me which code i should read.
regards

Kazi:

As I have posted several times on this forum, one of the major things that a practicing engineer has to learn is how to do the research necessary to determine what the rules are that apply to his particular problem. Kazi, I think you may have just found the next of many defining moments in your career. Best of luck!

There are two standards that may be relevant. They are BS 1306 (Specification for copper and copper alloy pressure piping systems) and ISO 4413 (Hydraulic fluid power. General rules relating to systems).

Pulsing pressures and vibration are both major factors that can influence the integrity of a hydraulic system. I don't believe there is a standard that will cover this design aspect fully for your application. The manufacturers of the tube, components and connectors should be approached for info. They may even have fatigue test data that you can use. However, you are probably looking at doing individual stress analysis on each component and a fatigue analysis acc. to ASME VIII Div 2.

Also, if your system involves small bore tube and the tube is to be bent then the fatigue strength will be affected by the bend radius and percentage ovality. CAESAR II would work out code SIF's that would not take this into account.