"I'm a Enganeer...I'm a Engenear....I'm an Enginear...................I'm good at math" Sorry for the spelling typos in this one! Hope you all can forgive me ;) Also, to add the solver: Check "Solver Add-In" not the "analysis toolpak"! The analysis toolpak is cool too but that's for a later video! ;) Thanks for watching!
The tensile load is assumed to be distributed evenly over the cross sectional area. In reality it's localized and would be highest at the hole and reduce towards the sides of the part. So I suspect it would start to fail in tension at a lower load than indicated. Please comment. I really liked the video and I learned several valuable capabilities in Excel.
It might start to yield in tension near the hole but when steel is taken to ultimate strength tests show this to average out and the stress concentrations don't matter. This is with respect to common steels used in structural applications. If you were bolting high strength heat treated parts the behavior could be different.
Like to see a spread sheet for rotational torque in the same way, for example torque arm bolting and or drive shaft flange connections. V nice though, thanks.
Conceptually this is correct but if you start applying this to building design there are a lot of the particulars that aren't quite in accordance with building codes such as AISC.
Your calculations do not include the friction put into the plates by the bolt's clamp load. You have modeled your bolt as a simple pin. If this fastener is torqued whatsoever, your calculations become invalid.
“Conservative” is relative the the intent of the design. But I think i understand what you are saying and believe you are correct. There are really three “levels” of failure in a joint like this….1) the point where shear force overcomes friction force causing slip of the plates 2) the point where the shear force overcomes the yield strength of the pin or plate and the material deformed 3) the point where the force overcomes the ultimate tensile strength of the bolt/plate material and fails entirely. Up to us as Engineers to understand which one(s) we need to consider based on the intended use of the design. Some connections we WANT to completely fail at or above a certain load, there are scenarios where no slip is desirable - where the friction force is what bears a load, and of course there are scenarios where all we care about is to avoid any kind of yield/ultimate failures. Here is a link with some good info. www.bgstructuralengineering.com/BGSCM14/BGSCM004/BGSCM00402.htm
In this example I believe I just used a generic value for steel. In practice you would get this from the real properties of the material you are using (which would be acquired from the material supplier or through your own testing)
First of all, thanks for the video. It was helpful and...free. So I have no right to complain, right? Right. I will just make a remark: you are speaking so fast !!! It feels like all young Americans are trying to speak as fast as possible. It's so annoying.
I (I’m sure everyone else reading your comment) would love your explanation as to why this is wrong… Is it wrong because I don’t consider friction? If so I would suggest you mean “incomplete”, not WRONG. The idea behind the video was to demonstrate some basic concepts and to show some capabilities of excel to help with it.
