Calculus: Verify Thick Walled Cylinder Equations

Ketav
Messages
4
Reaction score
0

Homework Statement



I have a system of two ordinary differential equations as shown below. I have to prove that the Lame's exact solutions for a thick walled cylinder loaded by internal pressure satisfies the equations.

The next step is to integrate the equations to obtain an equation for U and radial stress

upload_2016-11-8_17-15-31.png

Homework Equations


How should i go about the solution of this problem

The Attempt at a Solution


I have tried to find solutions for this but get stuck after the substitution of all given info[/B]
 
Physics news on Phys.org
I have tried to substitute the equations but for the hoop stress I obtain the relationship between b and r as one.
If anyone has any suggestions, I will be very thankful to you.
I have tried solving the differential equations however, i get to a point where I get d2u/dr2 + i/r du/dr + u/r=0 and get stuck with integration constants
 
Ketav said:
I have tried to substitute the equations but for the hoop stress I obtain the relationship between b and r as one.
If anyone has any suggestions, I will be very thankful to you.
I have tried solving the differential equations however, i get to a point where I get d2u/dr2 + i/r du/dr + u/r=0 and get stuck with integration constants
This is really a math problem. I'm going to move it to the math homework forum. Please show us your work in doing the substitutions.
 
So I've done this,

now I am confused about the integration. its a double integral but the boundary conditions are for r and sigma r
upload_2016-11-15_1-0-33.png
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top