Optimize the cylindrical tank of given Example for minimum weight by changing the laminate configuration but not the material. Use the carpet plots E-glass- polyester. Note that approximate values of Ey and Fy can be obtained from the plots for Ex and Fx by interchanging the values of α and β.
Example
Design a circular cylindrical tank with closed ends subjected to an internal pressure p = 1.0MP a. The dimensions are: length L = 2.0 m and diameter 2a = 1.0 m. Use a load factor α = 1.15 on the load and a resistance factor ∅ = 0.5 on the FPF strength values.