Structural Design & Scantling with ISO 12215

[Pablo Sopelana]

Hi @Alan Cattelliot ,

Thanks for the input.

Not sure about what you mean by "misleading".

Let me explain how I see it from my point of view:

We have this course where we teach about "Structural Design" and also about "Scantling with ISO 12215". The course's name is "Structural Design & Scantling with ISO 12215" (https://navalapp.com/courses/structural-design-and-scantling-with-iso-12215/).

We have included this thread in the "Education" part of the forum. Our understanding is that the people reading this thread will understand that we have this course where we discuss these two subjects.

Also, in the part of the course where we focus on ISO 12215, we mention what is positive about the standard and also its limitations. But the fact that the standard has limitations does not change the fact that the course focuses on both "Structural Design" and "Scantling with ISO 12215". Therefore its name.

 

[TANSL]

@Alan Cattelliot , I greatly respect your comments, always interesting and clarifying. On this occasion, however, I think I do not fully agree with you. I don't know how to distinguish at this moment between scantling with ISO, according to ISO or following ISO advice. What is clear to me is that if the ISO says that the design pressure to be applied is one of a certain value, I believe it and use that value. If the ISO tells me that the maximum admissible tension must be a certain one, it seems to me very good that the materials that I use do not exceed it. If the ISO indicates a procedure, accepted by everyone, to analyze the stresses in each layer of a laminate, I use that procedure. If the ISO tells me that, given the diversity of opinions that could exist, use certain formulas, recognized throughout the world, to calculate the mechanical properties of a compound, I, delighted with life, use them. If the Administration of my country delegates the approval of my calculations to some entities that prefer to have the calculations presented to them as indicated by the ISO, I prepare the information as they like (I even blatantly copy the formats to expose the results expected by the ISO). And, of course, not only with the ISO but with any other regulation, from any Classification Society, the values they ask for are always the minimum admissible. The calculator can put the value he wants, as long as his structure forms a balanced set, and the required minimums are exceeded. If acting like this is called "scantling with ISO", then I, for my part, am delighted.
Anyone embarking on scantling a hull, or trying to teach how "it" is done, should have minimal experience in this discipline and shipbuilding. Scantiling, in my opinion, overlaps between the conceptual project and the development engineering of the construction plans. You can't say what to do without knowing how to do it. But that is an opinion, I think, very particular since many tutors of courses like these do not yet have such practical experience.

 

[Alan Cattelliot]

The important fact to keep in mind is that ISO prescribes minimal scantlings, based on statistical data, but does not take into account structural details of every possible configuration, nor some particular efforts, that would add to the "local" efforts calculated with the standard. As a consequence, a boat could be ISO compliant, but with an insufficient local scantling. Load paths are not described in the standard, and any user of the standard should be able to determine by itself which load and which boundary conditions are to be used to design any part of the boat.

The strenght of the materials is also idealized in the standard. As a consequence, it is important to insist that every builder should verify its materials characteristics, by testing in a recognized laboratory, or at least, by making some flexural tests with a correct apparatus. This is especially important for composite materials, which mechanical characteristics will vary a lot, regarding the materials used, the building method and the building conditions.

I am very delighted that the use of the ISO standard could be spread, providing the fact that it is rigourously established what can be done with this standard, and what cannot be done.

 

[Pablo Sopelana]

@Alan Cattelliot , thanks for your comments. I subscribe: "a boat could be ISO compliant, but with an insufficient local scantling", and also "it is important to insist that every builder should verify its materials characteristics, by testing in a recognized laboratory"

In your comment, you mention composite materials, and I wanted to say that we also have a complete course dedicated to them: definition, design, and manufacturing. The course is "Composite Materials 1": Composite Materials 1 https://navalapp.com/courses/composite-materials-1/

As one of the students has put it regarding the course "Composite Materials 1" << the information presented in it is very valuable, and I did not find it with this amount and depth anywhere else. I appreciate the effort and time spent to collect this information because, as I see it, it requires professional experience in the field to collect it. >>

As is the case with "Structural Design & Scantling with ISO 12215" (Structural Design & Scantling with ISO 12215 https://navalapp.com/courses/structural-design-and-scantling-with-iso-12215/), "Composite Materials 1" also provides calculation templates. Moreover, in "Composite Materials 1" we also guide the students in the process of creating them:

 

[Pablo Sopelana]

If you need/require any clarification on the LL rule, please do not hesitate to ask...

I have taught at post graduate level, so I know a lot of preparatory back ground work is required for teaching... so good luck.

Thanks @Ad_Hoc, your offer to help is much appreciated.

In my experience you need to separate rules from practice.
Many people can and do learn rules of structures using the said rules. But very very few actually 'understand' structural design...the practice of the theory one is taught.
Having examples of boats etc...is good and does lend itself to degree of understanding 'practice'. But understanding how structures "work"...and why..is the key to being a structural designer, of sorts.

I totally subscribe to what you say.

 

[TANSL]

I subscribe: "a boat could be ISO compliant, but with an insufficient local scantling"

Exactly the same can happen with a boat calculated with any Classification Society. That depends, above all, on the designer, not on the standard applied.
I wonder, Pablo, in which chapter of your scantlings course can be applied what you learned in the course on composites. Both courses cannot be independent, as I think you want us to understand. Thanks.

 

[Pablo Sopelana]

Thanks, Ad Hoc, one more time, but why don't you inform yourself correctly before speaking?. You make statements based on your own assumptions (facts!, facts! as a great friend of mine bellows) and that is not right, it is not honest.

I confirm this is a fact. @TANSL , you have deleted your own thread, probably (what comes from now is my personal opinion) after you realized your writing was showing much more about you (I mean, the real you) than you actually allow others to know. And, I imagine, this is something you cannot stand.

@TANSL you know that we both know each other in real life. You also know that I know who the real @TANSL behind the mask is, and I don't mean the name, but the professional and also his personality. And I can imagine how the fact that you know I know could be driven you crazy (= annoy / irritate).

 

[TANSL]

I confirm this is a fact.

What exactly is "a fact", Pabl0, could you, please, explain what are you talking about.
I asked the moderator to delete my own thread because you were using it to give yourself visibility on this forum, which you greatly need while I don't. By plagiarizing my course you were saying that you do the same as me and that is not true. Now you have started your own thread, which is what everyone does when they have something to say, and I take advantage of it to clarify some of the half-truths that you tell in it. Also, of course, I take the opportunity to try to make everyone see the difference between the original (my course) and the copy (yours).
But speaking of something else, Pablo, you scare me because of the knowledge you seem to have of me and my circumstances. I don't know if you know something about me that I don't or if you're just telling us about a horror movie.
I have no frustrations, that I know of, but of course you will know better than me. Please, please, if you know something, tell me, even in this public forum.

 

[Ad Hoc]

.... As a consequence, a boat could be ISO compliant, but with an insufficient local scantling. Load paths are not described in the standard,....

Indeed.
Understanding load paths, is the key to understanding structural design and analysis.

I have reviewed and surveyed many boats in the past - all "class approved".
And yet...they fail owing to a lack of understanding of structural design and more importantly localised details.

 

[Ad Hoc]

... because you were using it to give yourself visibility on this forum, which you greatly need while I don't....

What an incredibly arrogant statement.
This is not TANSL's Forum, ergo it is not your forum, ergo, it is open to anyone and to post on any subject they like. It does not require your approval and it does not require you to agree or disagree with the postings/subject.
Whether one needs "visibility" is irrelevant. But on that subject, it is clear you require visibility as you come to this forum, as many do, seeking advice and guidance on subjects you know little about.

This forum is to help, guide assist those that are requiring such help and guidance in any issue marine related. And importantly, it is open to anyone and not one persons ego.
Just as you have requested help and guidance endlessly over the years on subjects that you do not understand and/or know the answers, noted:
Here and
Here and
Here and
Here and
Here and
Here
to name but a few of many....

Since as you note:

...I am not an expert on strength of materials ...

Which is fine, hence coming to the forum for assistance and help - as per the MO of the Forum.

But as always, your posts/threads very quickly deteriorate.
Which clearly suggests it is not about learning for you, it is about "visibility" of attempting to show you know the answers others seek, and must not be questioned.

... and I take advantage of it to clarify some of the half-truths that you tell in it.....

No, this is hijacking....as your usual MO when you are questioned on your highly questionable claims.
When a poster praises you, you are full of adulation towards them, since you covet praise.
But once a poster questions your statements and lack of understanding on a subject, out come the polemics, truculent and downright rude behaviour towards said poster.
Thus your 'behaviour' for "visibility" is indeed, clear to anyone reading the forum posts.

So, unless you have something to contribute to THIS thread on the subject matter at hand, may I suggest you start your own thread - again - and leave this to those wishing to add to what has already been posted, for the progression of others in their quest for more information and knowledge. Just as you constantly wish to do yourself.

 

[Ad Hoc]

... "a boat could be ISO compliant, but with an insufficient local scantling", and also "it is important to insist that every builder should verify its materials characteristics, by testing in a recognized laboratory"...

Indeed, as a brief posting noted HERE also supports.

 

[TANSL]

So, unless you have something to contribute to THIS thread on the subject matter at hand, may I suggest you start your own thread - again - and leave this to those wishing to add to what has already been posted, for the progression of others in their quest for more information and knowledge. Just as you constantly wish to do yourself.

Since you have not contributed anything to the topic of this thread either, I suggest that you also start a new thread in which you pour your, always affectionate, opinions about me.

You are right, I have entered this forum, first of all for entertainment and, given the high level of knowledge of its members, to ask for help on various topics, on several occasions, or to exchange opinions, indicating, when that was the case, that I am not an expert on many topics. That doesn't mean I don't understand them or can't talk about them (and I don't need your consent). Also, even though I am not an expert, I am able to see clearly when someone does not know what they are talking about, has no experience or tries to convince us that they know more than they really do. That is why I have faced you so many times and that is the origin of your appreciation for me.
As I have told you on several occasions, and I repeat now convinced of it, between your admirable use of the English language and my knowledge of naval architect and naval engineering we would form a fantastic duo. Consider the opportunity I offer you, please.

 

[Ad Hoc]

Dear oh dear oh dear...

You still don't get it do you.
This is not about YOU...despite your own paranoia telling you otherwise.

Replies, certainly mine, are based upon what someone has stated or claimed, and not the person.
I don't know you from a bar of soap, nor do I care. What I do care about is misinformation and false claims/knowledge that are never supported by any facts, just subverted opinions as facts.
For those with an understanding of comprehension...these are poles apart!

If you provide facts and independent support for such where required....you would receive no replies correcting you!
Simple..

Now you have had your usual tantrum, please, for the sake of anyone else wishing to learn on this thread...start you own thread and go bleat to others how important you think you feel you are...

 

[TANSL]

All's well That ends well. For my part, the conversation with you is over, but I reaffirm everything said in post #27. I still believe that I have the right to intervene, even if you don't like it, in this thread. I love you too, @Ad Hoc.

 

[Pablo Sopelana]

Hi,

I just wanted to post an update about the "Structural Design & Scantling with ISO 12215" course (Structural Design & Scantling with ISO 12215 https://navalapp.com/courses/structural-design-and-scantling-with-iso-12215/), which is currently open for Early Access enrolment.

Yesterday we added nine new video lessons to it:

Part 1 – Initial Considerations
- Frame of reference

Part 1 – Fundamentals of strength of materials
- Composite Materials. Physical properties
- Composite Materials. Mechanical properties: the stress-strain curve

Part 2 – The ISO 12215 Norm
- The rudder: geometry
- The rudder: forces and design

Part 3 – Practical examples (composite materials)
- Calculation of composite properties
- Calculation of a monolithic bottom panel – Part 1
- Calculation of a monolithic bottom panel – Part 2

Some unexpected activities prevented us from finalizing last week all the videos related to Parts 2 and 3. We are expecting, however, to be able to do it during this week (latest beginning of next week).

The launching date for the whole course, August 7th, remains unchanged.

We expect to upload more videos related to all three parts between today and tomorrow.