Figure 3.4: State of stress (a) in x1, x2, x3 system
(b) with x1-x2 andx2-x3 planes of symmetry |
Alternately, if we consider x1-x3 as the second plane of material symmetry along with x1-x2 as shown in Figure 3.5, then
 |
(3.28) |
And
 |
(3.29) |
This gives us the required strain relations as (from Equation (3.12))
or in contracted notations, we write
Substituting these in Equation (3.18) the function W reduces again to the form given in Equation (3.25) for W to be invariant. Finally, we get the reduced stiffness matrix as given in Equation (3.26).
Figure 3.5: Material symmetry about x1-x2 andx1-x3 planes |
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