Page 241 - Plastics Engineering

224 Mechanical Behaviour of Composites
Solution This stacking sequence is similar to that in Example 3.1 1 except
that in this case the laminate is not symmetrical. As shown in Fig. 3.27, the
centre line of the laminate is in the middle of one of the plies and
IQ = -0.25, hl = -0.15, h2 = -0.05, h3 = 0.05,
h4 = 0.15, h5 = 0.25

Fig. 3.27 Non-symmetric laminate

The approach is the same as before. must be determined for each layer as
shown below and thus the values in the A, B and D matrices.

- [ 1.6; 16 4.20 x 16
Ql = 4.20 x lo3 1.51 x lo4
0
4.17 x 104 1.98 x lo4 3.42 x 104 1
7.28 x 104 3.44 x 104 4.17 x lo4
3.44~ 104 2.80~ 104 1.98 x 104

7.28 x 104 3.44 x lo4 4.17 x 104
3.44~ 104 2.80~ 104 1.98~ 104
4.17 x 104 1.98 x 104 3.42 x 104
- 7.28 x 104 3.44 x 104 -4.17 x 104
Q4= [ 3.44 x 104 2.80 x 104 -1.98 x 104 1
-4.17 x 104 -1.98 x lo4 3.42 x lo4
- 7.28 x 104 3.44 x 104 -4.17 x 104
Qs= [ 3.44 x 104 2.80 x 104 -1.98 x lo4 1
-4.17 x 104 -1.98 x 104 3.42 x lo4

l5
D = - CDf [(hf l3 - Wf-lP]
3
f=1