I want to understand what the effects of a flanged hole on a ribs mechanical properties are in comparison to having no hole in the rib at all.
The end ribs in our RV-10's horizontal stabilizer:
Looking at the ribs, I think that the large holes will significantly reduce the rib's tensile strength. I however believe that this is irrelevant, as it is still significantly higher than the forces which can be transferred by the rivets. Hence, the rivets are still the weak link. Is this correct?
My other assumption is, that the flanged edges of the lighting holes will increase the ribs stiffness. Is this correct and by how much?
I therefore believe that a rib with flanged lightning holes is superior to a rib without any holes. It also saves weight.
Am I on the right track? Are there any disadvantages in putting flanged holes in ribs? Is there possibly an easy to understand explanation somewhere on the internet? I searched, but probably didn't use the right terms.
Oliver
The end ribs in our RV-10's horizontal stabilizer:
![2017-01-27_184546.jpg](/proxy.php?image=https%3A%2F%2Fi1.wp.com%2F2skywalkers.files.wordpress.com%2F2017%2F03%2F2017-01-27_184546.jpg&hash=c138b4e38fcfa7467847fedfcb968265)
Looking at the ribs, I think that the large holes will significantly reduce the rib's tensile strength. I however believe that this is irrelevant, as it is still significantly higher than the forces which can be transferred by the rivets. Hence, the rivets are still the weak link. Is this correct?
My other assumption is, that the flanged edges of the lighting holes will increase the ribs stiffness. Is this correct and by how much?
I therefore believe that a rib with flanged lightning holes is superior to a rib without any holes. It also saves weight.
Am I on the right track? Are there any disadvantages in putting flanged holes in ribs? Is there possibly an easy to understand explanation somewhere on the internet? I searched, but probably didn't use the right terms.
Oliver
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