questions about scantling (iso 12215 5-6 :2011)

thank you for your answers



fcfc understood me, it is a boat CE, I can not apply other scantling rules to certify the boat

What do you mean by "The problem lie in May wrinkling / crippling of the web."?

 

Here is something more concrete than theoretical. I assume you are desijning for an inboard mount. Here is one from Volvo Penta engine installation.

My comments are based on your desire to learn calculations and feed in detail info on other class rules if ISO is lacking on the subject. We are discussing the principles behind it rather than just push buttons on the software, otherwise I will just calculate it and give you the answer. I trust you will design in accordance with ISO as noted by fcfc.

 

I think you can compute your "slanted" stringer with annex H, using actual geometry. shear,tensile and compressive stress will be OK.

The problem will be 11.7.2 : web and flange buckling. Table 20 and 21 will not be applicable.

 

I have an idea, tell me what you think about it :
and I chose a commun laminate composition that may correspond
both to A-A' and B-B' sections





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rx i'm sorry but it is a outboard ,it is a Open with Central Console ,
the area where the distance between the stiffeners (port / starboard) is wider, there is a hold.

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TANSL : when I have time I will know you the problems that I spotted

 

marlin974, Your help will be greatly appreciated. Thanks a lot.
Ignacio

 

OB? Then it is much simpler in design.

I reviewed my ISO rules but could not find any rule or calculations on bottom pressure. I am surprised.

Normally I would grab my ABS or LR rule but found this one much simpler from Marine Composite by E Greene just to get you started. The book can be downloaded.

Noted that SCT of TANSL has several load models that will fit your requirements. Try it.

 

Found the missing link. It is ISO 12215 series. Not in my file. I have 8666 to 14946. Sorry for the confusion.

 

hi,

what it means σact and Tact , where these values ​​come from?

I thought it was max. values of column 19 and 24 of Table H4, but i'm not sure

thank you

 

Dear marlin974, you should obtain a copy of ISO 12215-5 and read it. On page 52 (of my norm) explains what are the variables which you are asking for.
If I may, I will give you advice based on my own experience: the scantling with ISO 12215-5 (or any other) is not possible if you do not know it. I'm not saying that you need to understand what it does, but just to meet her.
Knowing this fact, I have tried my program "SCT" had the greatest number of explanations for a non-expert user could use it with "relative ease" but always need a minimum knowledge of the standard to which he aspire. That's why I ask for a feedback from the users, to know their difficulties. (I hope you all can forgive the marketing I do on "SCT")

 

hi TANSL,
I have all iso standards (légal copy) for CE certification of a boat,
I've bought at FIN http://www.fin.fr/frameset.asp?langue=gb,
'and I try to understand the best as I can

my problems are just the understanding and interpretation of some points that no software could do it for me,
because if I do not have inputs values to insert ​​in the software I can not do anything,

page numbering is not the same according each translation , i've got french vesion ;

I know where these variables are in iso, my question is how to get their values?

do you have french version demo of SCT ?

 

I think the values σact and Tact ​​are actual values, those obtained from the calculation and in Table H.4 (in my copy of the standard) are in column 19 and 23 respectively.

 

Annexe H

hello,
does anyone know how should I do to analyze a panel having an aspect ratio l / b <2, with Annex H of the ISO,(isotropic and orthotropic)
because I'm not sure of the procedure.

that is to say what must be taken into into account
what value should i change in table H2

thank you

 

I had no answers



This is what I'd like to know more exactly:

question 1 :
Does the equation of Shear force (33) change?
(when i use Mdl (analysis on large side l)

Eq 33 : KC^0,5 x KSHC x P x b X 10^-3


I guess Kc = 1 because the curvature in the large direction(l), is not borne by the iso

should I replace b by l in equation?
meaning : KSHC x P x l X 10^-3 ?


question 2 :[/U]
should I replace b by l in the H2 table,

I'm waiting for your help
thank you

 

I think you're wrong,
read the beginning of Appendix H, 1st page


"if the ratio of the panel> 2: The panel must be analyzed as a strip (H2 method)(1mm), otherwise as H3 method, according to the two main directions"(that is to say as a plate B x l) (this is a translation, i don't have english version)

it makes no sense to use EInab=EInal,i tried it,

if the panel is isotropic,
therefore flexural stiffness is the same in both directions,
by applying H2.1.12,
Mdb will always be greater than Mdl,
that is to say, there is no need analysis in the direction of "l",
if the direction of the panel b is in conformity with the standard
(" ​​l" side, will inevitably be ok)



I think the shear force of the equation, should not be changed because it is not mentioned in H2.1.12,
after analysis, the H2 method is to check the bending
in both directions of an orthotropic panel,
with a size of L = b, there is only the rigidity which is different,


in short, a square having side panel bxb, so the shear is the same, the aspect ratio, are already included in the formulas (ksch)


H2.1.12 is only for Orthotropic panel



There are still survivors of the forum, where everyone is on vacation

please, I would like to have some feedback,

if you have assumptions, or better yet you have the solution please do not hesitate to intervene on the thread


after this, I summarizes my question:
How to analyze an isotropic panel with: l / b ratio is <2 .


Now I will try to analyze as with Annex H3
that is to say as a plate, and I'll let you know.
fd x l and Md x l


________________
if the standard had set an example for this case, it would be simpler, they prefer to show an example of panel (H2)
for which it is not necessary to use Schedule H because too Pessimistic with monolithic
A sample calculation for a sandwich complex with H2, would have been welcome, panel with <2, or different material as layer and glass and carbon),
________________



thank U