monocoque plate equivalency

[Nachsh]

we are developing our first monocoque and working hard on the SES laminate tests those days.
we figured we can get good EI results for laminates that are more 90/0 oriented (more layers of 90/0 than 45/-45).
i wonder if it is allowed to have a plate (side impact strc. for example) with better E1,E2 for certain coordinate sys.

any help or advise would be appreciated.
Nachshon, BGU Racing

[mech5496]

Your observation is correct and indeed, different layups are allowed for different areas of the monocoque. Good luck with it!

[Nachsh]

Hi Harry.
different layups are allowed. my question is, if it is allowed to have directional layups for critical areas (like the side impact strc.).
for a radical example: am i allowed to have only 90/0 fib. directions for the side impact?
this obviously would have a good E1,E2 for the original coord. sys. and bad E1,E2 for a 45 deg. rotated sys. but would pass the bending test of the SES.

[mech5496]

IMO, yes, it should be allowed. There's no wording prohibiting it on the rulebook, and everything not prohibited is legal, right? In theory your entire tub could be comprised of 0/90 layers entirely, as long as it passes all tests specified, although you will find that this is not really a bright idea. I would contact the rules comittee though, an official answer is much better than assumptions based on rational thinking.

[Nachsh]

thanks!