How Does Deformation Measure Change with Large Rigid Body Rotations?

[sara_87]

Homework Statement

What does it mean when a measure of defomation is 'not invariant with respect to large rotations of the body as rigid'?
i found that a measure of deformation is a 3x3 matrix:
cos(a),0,0
0,cos(a),0
0,0,0
where a is a constant
so why does this prove that this measure is 'not invariant with respect to large rotations of the body as rigid'?

Homework Equations

The Attempt at a Solution

 

[tiny-tim]

i found that a measure of deformation is a 3x3 matrix:
cos(a),0,0
0,cos(a),0
0,0,0
where a is a constant
so why does this prove that this measure is 'not invariant with respect to large rotations of the body as rigid'?

Hi sara_87!

I think it means that the deformation is only in the x and y directions, so if for example you swap round the x and z directions, the matrix will be different.