# Principle Second Moment Of Area - L shape.

1. Jan 11, 2012

### Roomie

EDIT: I meant to place this in Engineering help. Would a moderator please move it there? Thanks.

1. The problem statement, all variables and given/known data
I need to work out the theoretical principle second moment of area for an L shaped specimen I have.

http://dl.dropbox.com/u/630750/Screen%20Shot%202012-01-11%20at%2013.20.50.png [Broken]

I have attempted this but I'm getting an answer thats way off the experimental data.

http://dl.dropbox.com/u/630750/Screen%20Shot%202012-01-11%20at%2013.11.07.png [Broken]

I first have to work out IA, IB and IAB for this specimen.

Then convert it to Ix and Iy using a Mohr's circle. (The principle second moments of area)

http://dl.dropbox.com/u/630750/Screen%20Shot%202012-01-11%20at%2013.13.53.png [Broken]

2. The attempt at a solution

I've made an attempt at this by splitting the L shaped section into 2 parts.

Here is my attempt:
Page 1: http://dl.dropbox.com/u/630750/5.jpeg [Broken]
Page 2: http://dl.dropbox.com/u/630750/6.jpeg [Broken]

I then used these on a Mohr's Circle to work out Ix and Iy, and I got those to be Iy = 1.2x10-9 and Ix=1.24x10-9

If anyone could check this and see where I've potentially gone wrong I will be hugely grateful.

Last edited by a moderator: May 5, 2017
2. Jan 12, 2012

### Roomie

Anyone?

3. Jan 12, 2012

### Roomie

EDIT 2: I've sorted this now. Please Ignore.

Last edited by a moderator: May 5, 2017