huangyhg

bolt design and dimensioning
can anyone give me a hint wher to find a program or a formula to calculate the number of bolts and dimensions for an example as the one on the picture below? (its a simplification of the problem)
thanx
i think this is a good link for you to start with. i am assuming that you are an engineer or have engineering background.
regards,
lutfi
oops! i forgot to paste the link. here it is:
i'm having a little trouble making out those arrows in your figure. is that two forces both acting down or is it supposed to be representing torque? it looks like vertical load acting down to me. every thing i'm going to say from this point is assuming this is the case. note the assumptions presented on the page that lutfi posted. first,the gusset plate is perfectly rigid. for the type of loading you seem to be showing here i don't think this would be a good assumption, unless the plate is very thick. what's very thick? depends on the loads.
also, this would cause a prying action which would put the bolts in tension. i just skimmed the ohio state page but i'm very familiar with the concept. this is for a pattern of bolts that's eccentrically loaded and resisting the applied moment by shears only in the bolts. yes, they talk about combining shears with tension and you will need this for your case but you need to understand where this is all coming from.
boy, the more i try to explain the more i realize this is kinda complicated. let me just cut right to the chase and tell you my thoughts. first, i don't think the bolts furthest away from the rod will be picking up much load. you may be saying, "but that's just the opposite of what the oh page is saying!". re
hi tiasimo
from your diagram you clearly show a torsional load on the end of the rod and therefore all your bolts are in shear and are not subject to bending or prying action.
you need to find the centroid of your fixing pattern and resolve forces on each bolt. the bolts furthest away from the load will carry a greater portion of the load. lufti's link to that site of forces on fasteners is all you need.
one word of caution though use a good safety factor, i say this because unlike rivets which completely fill the hole there put into, bolts don't and therefore you may find in practice that not all bolts are taking the shear (ie bolts that don't come into contact with the side of the hole won't take shear, these bolts generate friction forces between the two plates only).
regards desertfox
how is that clear when both arrows appear to point down?
hi dozer
fair point i thought that it was just round dot didn't realise it was an arrowhead, i assumed he was indicating a couple.
however if the rod was in bending one would expect the force to be shown on top of the rod not tangential at the mid point.
regards desertfox
hi yourself desertfox
maybe tiasimo will reappear and clear it up for us. at any rate, lufti's link is a good one and should be very helpful.
sorry for not answering fast, but i cannot login with my normal user, so i had to make a new one.
thanx anyway
to clarify the problem...
i simplyfied the problem to a 1 downward load of 20 tons, assuming that my rod is completely rigid. see underneath the real problem so you can understand the problem.
?

__________________
借用达朗贝尔的名言：前进吧，你会得到信心!
[url="http://www.dimcax.com"]几何尺寸与公差标准[/url]