Question

Qustion

Answer 1

Looking for the torque a long the whole entire rod.

Answer 2

hey you there?

Answer 3

I am currently working on another problem. I have a solution for it too but not getting the correct answer and I am sure my solution is correct. Lets look at this one for now.

Answer 4

I was comparing my answer to the solution manual. I didn't get what they were doing so that is why I am here.

Answer 5

Here's what I've got so far:
using N, mm (N/mm^2=MPa)
G=70000 MPa
a=1500; b=400; c=1100;
t=-4400 N-mm/mm; tc=4100000 N-mm; td=-2200000 N-mm;
Following values are after independent applications of t, tc and td.
theta_b= \(\Large \int_0^a \frac{tdx (x)}{GJ}\) = -0.17565 rad [ using theta=TL/GJ]
theta_c=tc*(a+b)/(GJ)=+0.27643
theta_d=td*(a+b+c)/(GJ)=-0.23420

Do you have the same numbers?
If yes, then we can get the combined value for theta_b by prorating theta_c and theta_d.
Same goes for combined values of theta_d.

Answer 6

Also, a useful list of formulas are here:
http://www.engineeringtoolbox.com/torsion-shafts-d_947.html

Answer 7

There is no way to get the torque along segment AB?

Answer 8

i meant segment AD I am just having a hard time analyzing segment AB

Answer 9

I would analyze them separately, and use superposition to find the theta's.

Answer 10

How did you use theta_b = the integral.

Answer 11

taking the integral with respect to x?

Answer 12

Since rotations are additive, so we integrate like TL/GJ, replacing T by tdx, and L by x.

Answer 13

Actually dT = tdx.

Answer 14

Oh I see.

Answer 15

Hmmm interesting way to go about solving it. I will give it a go. I want to try something first though. Do you have time to look at one more problem? Part of a problem?

Answer 16

Just post it and tag or PM me.
At least I have decent Internet now! lol

Answer 17

okay sounds good. Thanks.

Answer 18

I will leave it to you to work out the details, and perhaps the combinations!
Remember, contribution of rotation at B from torque at C is prorated according to length,
but contribution of rotation at C from torque AB equals rotation at B because torque stops at B.

Answer 19

Yeah I am going to try one more thing before looking at what you suggested.

Answer 20

Good! Let me know how it goes when you're ready!

Answer 21

I will. thanks.

Answer 22

nvm I guess finding the angle of twist will allow me to find the torque

Answer 23

question. WOuld the torque in BC just be T = Tc - Td?

Answer 24

Yes, but strictly speaking, it's Tc+Td, and let the signs take care of themselves.

Answer 25

The torque applied between AB would also need to be included with the torque at BC right?

Answer 26

"finding the angle of twist will allow me to find the torque"
In this problem, all the torques are given, and the angles of twist are required...unless I misunderstood something.

Answer 27

Yes, to the extent shown in the previous drawing, i.e. Tab 's effect on B and C is the value at B.

Answer 28

Yes, I will need to find the angle of twists eventually. Okay I will solve using the angle of twist.

Answer 29

theta=TL/GJ, right?

Answer 30

Oh, forgot to mention, I have J=402578 mm^4.