[FSE] Antwort: Re: FSG 2011; SEF car E34

Čtvrtek Červen 23 09:38:42 CEST 2011

Dear Mr Fric,

I give you some answers down in your originaly email. 

With best regards

Ulf Bulling 
Fachspezialist / Specialist 
--------------------------------------------------------
DEKRA Automobil GmbH
Technology Center * Automobil Test Center * Abt.: AG71
Senftenberger Str. 30 * 01998 Klettwitz
Tel.: ++49.35754.7344-592 * Fax: ++49.35754.7345-500
datc na dekra.com * ulf.bulling na dekra.com 
http://www.dekra.com * http://www.datc.de
--------------------------------------------------------

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DEKRA. Alles im grünen Bereich.
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DEKRA Automobil GmbH
Sitz Stuttgart, Amtsgericht Stuttgart, HRB-Nr. 21039
Vorsitzender des Aufsichtsrates: Stefan Kölbl
Geschäftsführer: Clemens Klinke (Vorsitzender),
Wolfgang Linsenmaier, Dr. Gerd Neumann, Dieter Roth

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Ondra Fric <fricik na seznam.cz> 
22.06.2011 16:06

An
ulf.bulling na dekra.com
Kopie
FSE <fse na fel.cvut.cz>
Thema
Re: FSG 2011; SEF car E34

Dear Mr Bulling,

our last year car (more accurately our 2010 combustion engine powered car 
before splitting of the team) uses almost the same solution. The SEF we 
had last year was very similar to this year's one and it passed through 
check up correctly because it was considered as a frame diagonal member 
substitution and not as a monocoque.

I am not sure if I understood correctly to the shearing test. Is it meant 
to be some kind of a steel ball/cylinder pushed perpendicularly to the 
surface of the sandwich? How shall we support the sandwich? Does it have 
to be supported by desk with the hole of the same shape as of the 
impacting member? Is it necessary to fasten the sample against tensioning 
of upper skin?
I hope you understand my sketch that is attended at this email.

So if we will consider it as a monocoque side impact I understood your 
email that it is necessary to fasten it by bolts ("So your sandwich-panel 
is to use as an "Monocoque side impact" (see rule B3.37.3). "). Do I 
understand it correctly? According to my opinion it is not necessary to 
bolt it to the frame. I had calculated that bonding to the outer side 
surface of the frame tubing is sufficient.
Yes, we talkt to Mr. Steinfurth (FSG). And the result is that you should 
use (at least) 2 bolts per side (front/ back).

On the page 22 of the SEF you have marked that I used wrong surface of 
bonding for shearing and you consider it as tensional loaded. If I push to 
the outer skin of the sandwich it bends into the car and it means that the 
skins will slide on the outer side of the surface of the tubes where it is 
bonded (this is not brittle material as carbon). With such ductile 
material as aluminum it is not correct to think that the skins bends out 
of the bonding surface. Shearing on the surface between the tube and the 
sandwich as you have marked will surely occur but bonding at this place 
will be done only as redundant because of accuracy of manufacturing.
Pelase see my 2nd sketch at this email. If there is a bad worst case 
structur, that only  stress your sandwich panel. So your sandwich panel 
can crack in the critical areas and your side impact structure is limited 
in their function.

Concerning the shoulder harness we had already find the solution by 
gusseting to the main hoop and also supporting the firewall.

Best regards

Ondrej Fric

> ------------ Původní zpráva ------------
> Od:  <ulf.bulling na dekra.com>
> Předmět: FSG 2011; SEF car E34
> Datum: 22.6.2011 13:04:32
> ----------------------------------------
> Dear Mr Fric,
> 
> I have checked your SEF. My remarks you can find in the attachment. In 
> fact of your sandwich-panel we talk to Mr Steinfurth (FSG). So your 
> sandwich-panel is to use as an "Monocoque side impact" (see rule 
B3.37.3). 
> 
> At least I can't find your shear test to rule B3.31.3.
> 
> You status at the FSG website is changed to fail.
> 
> With best regards
> 
> Ulf Bulling 
> Fachspezialist / Specialist 
> --------------------------------------------------------
> DEKRA Automobil GmbH
> Technology Center * Automobil Test Center * Abt.: AG71
> Senftenberger Str. 30 * 01998 Klettwitz
> Tel.: ++49.35754.7344-592 * Fax: ++49.35754.7345-500
> datc na dekra.com * ulf.bulling na dekra.com 
> http://www.dekra.com * http://www.datc.de
> --------------------------------------------------------
> 
> **********************************************************************
> DEKRA. Alles im grünen Bereich.
> **********************************************************************
> DEKRA Automobil GmbH
> Sitz Stuttgart, Amtsgericht Stuttgart, HRB-Nr. 21039
> Vorsitzender des Aufsichtsrates: Stefan Kölbl
> Geschäftsführer: Clemens Klinke (Vorsitzender),
> Wolfgang Linsenmaier, Dr. Gerd Neumann, Dieter Roth
> 
> 
> Diese e-mail und beiliegende Dokumente können vertrauliche Informationen 

> enthalten. Wenn Sie nicht der Adressat sind, sind Sie 
> nicht zur Verwendung der erhaltenen Informationen befugt. Bitte 
> benachrichtigen Sie uns sofort über den irrtümlichen Zugang.
> 
> This e-mail and any files transmitted may contain confidential 
> information. If you are not the addressee you are
> not authorized to make use of the information. Please inform us 
> immediately if you have received it by mistake. 
> 
> 
> 

--------------------------------------------------------------------------------------------------------------------------------------------------------------
Ondřej Fric
CTU CarTech Electric - Formula student electric racing team
Czech Technical University in Prague
icq#:  394-760-523
tel:     +420 775 396 531

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