Skirt Allowable Stress in PVE Lite 2

[mechengineer]

The Skirt Allowable Stress.
I have another unpleasant experience with PVE lite and the support team working recently.
The case number is 00196823. If you are interested, please go to PPM Smart Community (you shall be a listened PVE Lite user). This may help you to understand what the after-sale service provided by PVE Lite support team is currently.
Please allow me simply to state the case 00196823 here and welcome all to comment.
Subject (revised): The skirt allowable stress shall be in accordance with AISC or equivalent, not ASME pressure vessel code.
The answered from the development engineer:
I agree that the allowable skirt stress could be based on design rules from AISC or equivalent. However, to the best of my knowledge, the general expectation from the vast majority of users, Notified Bodies etc. is to use the ASME or Code based computed allowable stress.
I replied:
PVE is to selectively treat customer requests according to the size the customer (the majority of users). There is discrimination against small companies.
For engineering design and technical issues, the requirements from major customers go beyond the engineering design principles themselves.
This approach discards the respect for those users from small companies and also goes against engineering design principles and professional ethics.
The Manager of Support team:
Requested the justification from a published document, interpretation based on research, adopted in practice etc.
I replied:
I showed up the Pressure Vessel Handbook (10th Ed) Eugene F. Megyesy that indicate the skirt allowable stress shall be for structural purpose.
And I asked the manager, what is the justification that PVE Lite uses the pressure vessel code allowable stress for the skirt? Any reliable justification from a published document, interpretation based on research (have had no answer till now from the support team)
The Manager of Support team:
He requested me to explain the allowable request of the Pressure Vessel Handbook and said that I think this case is done and requires no further discussion unless more data is provided or found.
I replied:
I really don’t understand what are the ‘more data’ you’re required. As you required, I already showed you the Pressure Vessel Handbook (10th Ed) Eugene F. Megyesy that state to use structural allowable stress for the skirt design, which is the published and widely used in the industry. Even if I don’t think that is necessary because that is a normal sense that structure design shall be as per a structural code and pressure vessel design as per pressure vessel code.
The manager of support team:
PV Elite Support and Dev are not in the capacity to change what is accepted in the industry.
I replied,
You are like saying that all errors/mistakes in PVE Lite are accepted in industry because PVE Lite has used in industry. The material allowable stresses shall be from the relative design codes rather than the vast majority of users, Notified Bodies.
The manager of support team,
If you wish to use AISC you will have to do a separate analysis. If you have evidence that this becomes accepted in industry we'd be happy to consider.
I replied,
I think that you may not know about the G-2 Supports Consideration in the code. You have been doing nothing on the study and research for it since the customer revealed this mistake to you. And instead of that, you keep asking customer to do this for you for free. You are extracting your customers' labor and technical resources for your business software for free. You are too much to request the customer to give you an evidence that this becomes accepted in industry. But also you have no any evidence that the skirt allowable stress used in PVE Lite accepted in industry except the software has used in industry.
Note: the case already closed by the namager without any further reply. PVE Lite has still used pressure vessel code allowable stress for the skirt.
PS: ASME Sec VIII Div 1 - Nonmandatory Appendix -G
G-2 SUPPORTS CONSIDERATIONS
The details of supports should conform to good structural practice, bearing in mind the following items (see Manual for Steel Construction, latest edition, by the American Institute of Steel Construction).
The skirt support design and allowable stress shall be as per AISC that confirmed by Appendix-G.

 

[mechengineer]

@r6155,
You have never responded directly to your wrong opinion I pointed out to you. When your idea is not correct but you advise other people to learn.
I have no objection to the importance of welding and flaw detection in the design and manufacture of pressure vessels. But it doesn't seem this is directly related to my topic to discuss here, because the skirt is a structural component (non-pressure part) which is not in the pressure vessel code scope. The confused guy is just you.
What do you say about other people if you don't know them at all? The way seems same as you would talk about your technical opinion here. It’s not very hurtful, but very insulting. Tell you, I had 8 years’ experience of pulling slide rule calculator and using drawing board to design pressure vessel in that time of 80’s. And the snap shot of the calculation is from a famous PV manufacturer (since 1940) in US. That is the same way to calculate the skirt thickness widely used in the industry, such Moss's Pressure Vessel Design Manual and others Pressure Vessel Design HandBokkes. But also, it clearly gives the allwoable stresses which are from AISC, not pressure vessel codes.
I'm answering you out of respect for this tech forum and you are MVP in the forum. There is no win or lose in technical discussion. That is to learn and help each other. What is needed is your sincerity, not sorry. If you are not happy, you may not participate in my discussion.

Regards,

 

[mechengineer]

@DG2,
Please read the last para. in my post:

 

[r6155]

@ mechengineer
Maybe ASME PTB-4 ASME VIII Example Problem Manual will convince you.

Regards

 

[GD2]

mechengineer,

If I understand your concern correctly, you had an unpleasant experience from the PVE Lite support team on allowable stress for skirt design per AISC rule as ASME Sec VIII Div 1 and 2 allows you to do.
My understanding is the following:
PVE Lite being an application primarily built on designing pressure vessels, most likely it will take into consideration the ASME Sec VIII code rules while developing the application.
Yes, Sec VIII direct you to use AISC rules for designing the supports and structures, but then you need to use a different application built with AISC rules. All Civil and Structural engineers will use the AISC based application for designing the supports and structures.
It's very normal in the oil and gas industry that we provide the loads to an Structural engineers and he/she will design the support/structure using their structural application.
Now, I see two options for you:
1. If you want to use PVE Lite for the skirt design, follow the Sec VIII Div. 2 para 4.3.10 rules. It will give you the load combinations to use with allowable stress.
2. If you want to use the AISC direction, give the loads to an structural engineer and he/she will design the skirt for you using AISC rules for load combinations and allowable.

In another way, I feel your question is like asking if an Apple phone can work with all Samsung apps. Both are smartphones.

Sorry, I don't mean to demean or insult you but to bring an understanding of what you have and what you are asking.


GDD
Canada

 

[Trestala]

@mechengineer, it seems you are concerned only for ASD and not LRFD. You can make a custom material in PVElite to address your issue using MATEDIT if you do not want to use ASME allowable stresses.

You do not need to argue with PVElite team on what is used in the industry. Also, several of the oil majors would specify to use ASME allowable stress for supports and lifting attachments as that is the more conservative design. That is just their standard practice and extra metal is cheap insurance.

Or you could just perform manual calculation for the support using PVElite output of the shear/moment profile under wind/seismic loading if you want to use LRFD.

 

[mechengineer]

@Trestala,
Yes, I can do it by using MATEDIT or by calculating manually.
See some comments from LinkedIn,
The skirt is a cantilever beam under the weight and bending loads and the pressure vessel is a cylinder under the internal/external pressure loads. The loads and failure modes are completely different. Thus the allowable stress for pressure vessels and the allowable stress for structure beam is a different concept. It's an incredible idea to exchange the allowable stresses so confusingly in technical.
For commercial purposes, the allowable stress is from major customer's requirement and go beyond the engineering design principles/rules themselves. I don't know how many just using software engineers would be misleading. This behaviour is disgusting.

Regards,

 

[david339933]

You reference Pressure Vessel Handbook 10th Edition. See page 76. Efficiency is in that skirt thickness calc.

 

[Trestala]

@mechengineer, that is incorrect. You can use Code allowable stress for supports if the material specification is from or have an equivalent in that Code (e.g. A283-C/SA-283-C).

Also, the pressure parts (cylinders) are also designed as cantilever beam under combined loading of pressure, weight, wind/seismic, and other eccentric loading. The difference from your statement is the direction (longitudinal/circumferential). Please study first how PVElite performs these calculations.

Also, PVElite does not have monopoly in PV Calculation softwares. Almost all Vendors where we procure vessels uses Compress.

As I said, you can just modify the allowable stress since you are still calculating in ASD.

 

[mechengineer]

@Trstala,
There are so many people confusing with the pressure part and non-pressure part analysis. To simplify the discussion we don't talk about the pressure parts analysis here. Thanks.

 

[Trestala]

@mechengineer, since you are referring to Bednar's and Moss' books, please read those books first and check again your replies here.

 

[mechengineer]

@saplanti,
Whether my knowledge is sufficient is non your business. On the contrary, I think your nonsense talk is more than enough. I has aleady applied to block you in my discussion. If you're not so ignorant yet, please leave here yourself. Thanks.

 

[mechengineer]

@Trestala,
No. I am not talking about the pressure part and how to calculate the actual stress on the skirt. Just talking about the allowable stress of the skirt. That's all. the resolution is that The skirt support design and allowable stress shall be as per AISC that has confirmed by ASME VIII-1 Appendix-G.

 

[mechengineer]

Another opinion from LinkedIn,

Normally Good Engineering Practice (or Industry practice) is for those area that are not included in codes and no ready formula to use, but this case is not.

 

[Trestala]

@mechengineer, you are confused about pressure/non-pressure parts. The difference lies in the loading and temperature. But both are under weight/wind/seismic/eccentric loading. So you still need to check the loading in longitudinal direction. Please check first how PVElite performs the calculation for allowable stress design.

If you will use AISC, you have to decide between ASD and LRFD and check the load factors if necessary. Do you understand those?

You are only focusing on allowable stress used by PVElite while the software actually doesn't limit you to use Code allowable.

 

[mechengineer]

@Trestala,
Sorry I can't understand you. Of cause PVE lite doesn't limit you to use Code allowable. PVELites uses the code allowable stress for the skirt that's exactly what I'm against.
Again, my opinion is very clear andsimple that is "The skirt support design and allowable stress shall be as per AISC that has confirmed by Appendix-G" rather than use pressure code allowable stresses. I have no doubt on how to calculate the cantilever beam. Your questioning about me is superfluous. Don't think others don't understand what others haven't talked about. For the dicussion point should try to be simple and clear, especially in the public medium. I do not know why you branch to grow new branches on a node.
I don't want to argue with you about what the pressure part and non-pressure part is if you think the skirt is the pressure part (it's been stated very clear that temperature loads are not considered here).

 

[Trestala]

@mechengineer,

Of cause PVE lite doesn't limit you to use Code allowable. PVELites uses the code allowable stress for the skirt that's exactly what I'm against.

It seems you haven't used or understand how the software works. There are workarounds with your problem as I've previously said. If you understand how to calculate per AISC manually, you can modify parameters in the software to get similar results.

As for the cantilever beam/combined loading design, please read the books you've mentioned.

 

[saplanti]

I leave your non-sense discussion myself since you do not have knowledge and respect on people that trying to give you direction. I hope you will understand what you have done in the end.

 

[mechengineer]

@Trestala,
I feel you are to much, what you worry about me may be just your own weakness. It seems you have not even know what is the point that I talk about even through I stressed to you many times.
Do you know where it shows the code allwable stress applied to the skirt in the calculation report of PVElite? If you are intersted, advise you to run PVE lite and study first. You have to buy the software and read the user's manual if you have not used before. Sorry, I'm replying to you in the same way as you speak to me. But we better stop here. What you advise me is more than enough. Thanks.

 

[Trestala]

@mechengineer, we have licenses for PVElite and Compress. And I have read those books and have done manual calculations. If you really know PVElite you should know it doesn't limit you to Code allowables. Try finding it in the software.

 

[mechengineer]

@Trestala, No worry and thanks.