Deflection in a Cantilever: Physics EPI

[John B]

Hey I'm doing a Structures and Materials EPI for physics and as part of it we are measuring the deflection in cantilevers when a force is applied to the end of the beam which is attached and fixed at a point on a desk. I was just wondering if anyone could explain anyon could explain Moment of inertia in such a structure and how i could determine it so i could collate a stress-strain graph. I have read up on this equation δ=[F(L^3)]/[3EI} δ=deflection F=force L=length of cantilever E=Young's constant I=moment of inertia but don't really understand moment of inertia. If this is too difficult to explain without me being a second year engineering student what sort of graph should I draw up given that I know the deflection of the beam and the downward force on the beam. I have attached a diagram of the cantilever the force is directed downwards on the beam located free end.
Thanks a lot in advance.

[pi]

OMG, I did a cantilever experiment for my EPI too :O

I'll upload it in a minute (I got A+ haha - no idea how my physics sacs were so good) Might help in some way


edit: yeah, moment of inertia is pretty tough stuff, I stayed clear of it. But honestly, looking at the MHS physics dep, there are probably only a couple of teachers who would get it anyway (and I didn't have one of those)

[John B]

Thanks that would be awesome. I've got Keyte this year so Physics is interesting to say the least.

[DisaFear]

I also did a cantilever'ish EPI, also had Keyte, but unfortunately, my documents no longer exist.
Had a spring at one end of the cantilever attached to the table, and a mass at the other end, and fulcrum point shifts.

Good luck with Keyte

[pi]

lol, "interesting" teacher to say the least, he gave me my "solid" foundations in yr 11 *cough*.

Feel sorry for you mate (I had the army cadet bloke in yr12 lol...), you're going to need a fair bit of self-directed learning

Uploaded mine

[John B]

Thanks a lot. I'll give it a read and work things out. Best of luck with Medicine 

[John B]

Hey Vegimite Pi thanks a lot. Just one question some of the equations didn't come through in the attachment, on page four what was the simplified equation of deflection and the overall relationships. I can see all the words just not symbols. So I'm assuming you grouped all no measured variable so as to create a simplified link between stress and strain so you could determine youngs modulus values later on in the practical.

[pi]

[John B]

You sir are the greatest. Thanks so much. Our groups going to use different strengths of wood instead of the varying lengths but the equations are a huge help.