Examples:

Example 4.1: Calculate  for AS4-3501-6 Epoxy material for fibre orientation of .

Solution:

Calculate the Poisson’s ratio  as

Calculate the reduced stiffness matrix entries in principal material directions as

Now, calculate  and  as from Equation (4.33), Equation (4.35) and Equation (4.36) with and .

and

Now, . This gives us

Example 4.2: In the above example, if the state of strain at a point in principal material directions is , then find the corresponding state of stress in global directions for fibre orientation of .

Solution:

We find stresses in global directions as

We calculate the strains in global directions as

And

Example 4.3: In Example 1, the coefficients of thermal expansion in principal material directions are . Calculate the stresses developed due to temperature rise of  in principal material directions as well as in global material directions.

Solution:

Stresses in principal material directions due to thermal strains alone are given as

Here, . Thus,

And stresses in global directions are