Attached plate to a stiffener.

TANSL,

to be honest I have not worked with ISO, so I cannot have an opinion. I just remember while working with ABS 1978 Rules a few years ago, you could not use the attaching plate for wooden members (as far as I remember it was clearly stated), that's why I mentioned it.

 

I, on my side, do not know the ABS 1978 and can not comment. What happens is that in the last 15 or 20 years the regulations have changed a lot, in particular as to the fibers and other inhomogeneus materials are concerned. Things, as always have greatly complicate. Before four formulas were sufficient to scantling a boat but now you have to know strength of materials.

 

TANSL,

ABS HSC 2015 states the following in regard to effective plating of stiffening members:

7 Effective Width of Plating
The section modulus and moment of inertia of stiffening members are provided by the member and a portion of the plating to which it is attached. The effective width is as given in the following paragraphs. The section modulus and moment of inertia of a shape, bar, fabricated section, or laid-up member not attached to plating is that of the member only.
7.1 FRP Laminates
Where the plating is an FRP single-skin laminate, the maximum effective width of plating for floors, frames, beams and bulkhead stiffeners is not to exceed either the stiffening member spacing or the width obtained from the following equation, whichever is less. See 3-1-2/Figure 6.
w = 18t + b
where:
w = effective width of plating, in mm (in.)
t = thickness of single skin plating, in mm (in.)
b = net width of stiffening member, in mm (in.), but not more than 18t

ABS HSC, Hull Construction & Equipment
Part 3, Chapter 1, Section 2, p.20

For ABS HSC, there is no specification regarding wooden members. This also applies to LR if I recall correctly.

Rules are indeed much more complex nowdays, not mentioning surveyor's interpretations of rules.

 

Sorry but no you didn't. You made a statement thus:

Which clearly states you assume all classification societies use the same methodology and thus end up with the same formulae. Thus incorrect.

As RX very clearly demonstrated and should be known by anyone using such rules, or conducting research.

Then you clearly do not understand your own question.

Do you add the weldment of a metal section to its modulus calculation...and there is your answer.

 

I guess if I recognize that you know more than I do, you'll be quiet. Well, yes, you have given me a tremendous lesson. On what ?, who cares, nobody cares. Thank you, once again, master. This thread for me is over.

 

I am constantly perplexed by your postings.

You keep mentioning your structure/ISO software to other posters and links to your website of the software. So either you are a software/computer engineer or a structural engineer. The evidence on this thread especially (and others) indicates the former. Since the question you ask on this thread is so basic it would only be asked by someone who is just beginning to learn about structures and moments of inertia. Thus, if it were asked by a student, it would be fair comment. Yet for someone who pushes their own structural software....it begs the very question....who does your structural analysis, since the basics appear to be beyond you, yet you wish to advise others on such.

Most odd...unless of course you are just beginning a course on structures, in which case..fair enough.

 

Let me speak Latin as your nickname suggests that you have mastered it: superatis hostibus regium is abstinere.

 

So you wish to deviate and deflect, as you always appear to do, rather than answer the question. That being are you a computer or structural engineer?

Either you understand structural theory or you don't. If you don't fine, just say so and let those that do, answer your question so you may be more informed on the subject at hand. But do not give the impression you do understand, by offering advice on such to others and offer software, on such matters from yourself, if you don't.

You can keep on misdirecting and deflecting not wishing to answer the question..but the longer you do so, exposes your lack of comprehension on the subject even more. It's your choice....

And in case you have already forgotten...the question posed is thus:

If you wish to learn, that fine. This website if for all that wish to learn more about a topic/subject. But i fail to see how the same poster seeking advice/information on the basics can then elude to educate others on such matters they seek knowledge on themselves.

 

I was wrong and so I recognized in my post # 13.
Ad Hoc friend, I am what I am but that should not you care to you. I just pretend to be judged by what I say and not for my academic qualifications. I know that the way of my writings in very bad but continue because, perhaps, the background is correct. When I'm wrong, I do, I have no objection to admit it, and I do not look for excuses to justify my mistakes. I do not like the people who first showing is the title of naval architect but I like them even less when these people treat others with arrogance and contempt, speaking from the rostrum of the great masters. I may have more academic qualifications than you. But that is not important.
Regarding my software, I pretend not teach anybody anything, I do not have enough "autoritas". All I say is: "If you have to make a certain calculations by hand, I offer my software, which automatically will do". I does not invent calculation procedures or new methods. What I try is to give tools to the designer so he does not waste time on routine calculations, with some assurance that it has be done the right thing and the possibility that amistake, and having to repeat a calculation, it is not a tragedy. All my software is aimed at giving the designer more time to think and to project, to prevent him from using his time in uncreative work.
Another issue: now I know what to do but let me ask you: when designing fiber boats with reinforced top hat, how do you consider the width of the plate associated with the reinforcement ?. Dont tell me, please, about the CS or the theory of pure bending. Just tell me what you do, because I want to have an opinion more. I assure you that I will be able to understand what you say, as much as you garnish it with great phrases.
Finally I will say that I respect you what you deserve, no more, so I advise you to avoid losing face again, trying to discredit me.
Thank you, on the other hand, to seek as much information about me. You flatter me. Best regards.

Thanks to the other participants that even disagreeing with me, have kept quiet conversation without feeling the need to call me ignorant.

 

Vkstratis- There is a rule by ABS regarding wood plating. Old one but still a rule to guide us.

There is also NK rule, which is similar to post 3.

Found also rule by GL regarding effective width.

Seems this rule is very much covered in order to estimate the moment of inertia.

 

rxComposite,


thank you. What is the GL rule name? Is it still in use?

V. K. Stratis

 

You are welcome. GL rule 2011 edition but I didn't bother to open it.

 

You are not helping yourself with your continual ripostes. So you say this:

So for this to occur the software needs to be programmed, and more importantly programmed correctly to provide the correct answer as theory suggests for consistency and quantitative analysis. I wrote my own for such once excel came onto the market, it is not rocket science for those that understand the theory and basic computing. You should search the forum for the spreadsheets offered by RX on composites, they are excellent.

Thus in calculating the modulus either it is known how to do such a calculation or it is not known. It is that simple. You are saying that your software automatically calculates the answer for the user. Well, if you do not know whether the attached plate of reinforcement is to be added or not, again, how on earth can you offer such software to others?...since your sowaftre will not know unless it is programmed correctly.

This is very basic structural analysis. Either you know how to do it, or you do not. Your post and replies clearly suggest you do not…..since why ask? If you are asking such basic questions, it is self-evident your software will not be correct.

To compound matters, you then suggest that all classification societies are the same. If you knew how to do the calculation and if you have used many different authority/society methods for compliance, as RX has shown, then you would know such a statement is false. They are not all the same. Again, either you know this or you don’t. Clearly you don’t.

Again, just showing your ignorance on the subject. It is not my opinion, it is simple structural theory that provides the answer. One does not guess at structures, one uses known structural theory for analysis. If you understand the theory the answer is very clear and obvious in there, irrespective of my “opinion” or anyone else’s. Engineering, especially structural engineering, does not pander to emotions, it is factually based.

 

GL is now part of DNV. Some rules have changed but not all.

You can find them here:
https://rules.dnvgl.com/ServiceDocuments/dnvgl/#!/home

 

Thanks, Asd Hoc.
Incidentally, I agree with you, anything RX posts in this forum is of great value and is based on his own studies and experience.