A notched (150 x 150 mm) aluminium plate (Figure 1) is used to reinforce the main...

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A notched (150 x 150 mm²) aluminium plate (Figure 1) is used to reinforce the main spar cap and subjected to 45 N.m and 57 N.m bending moments. The thickness of the plate is (8 mm), and the diameter of the circular hole is (10 mm). It is intended to replace the aluminium plate with a composite laminate. However, due to new design constrains, the total thickness of the composite plate should not be higher than (4 mm). The material properties of the selected carbon/epoxy laminate are given in Table 1. Assume that 0° and 90° plies do not contribute towards the shear strength of the laminate. Table 1: Material E₁ G12 V12 (GPa) (GPa) (GPa) 181 (GPa) 10.3 7.17 0.28 Figure 1: Aluminium plate properties of the selected carbon/epoxy laminate Ultimate Ultimate S(+45) (MPa) tensile strain 15,500 με compression strain 8.000 με 250 Ply thickness (mm) 0.13 A. Calculate the minimum number of control plies (0°, ±45° and 90°) that can meet the specified design constrains. B. Following the good practise rules for the design of aerospace composite structures, suggest an acceptable laminate stacking sequence. C. Determine the Margin of Safety (M.S.) of the proposed laminate (Part B) for Nx and Ny and discuss the safety issues of the composite plate based on the calculated M.S. values. A notched (150 x 150 mm²) aluminium plate (Figure 1) is used to reinforce the main spar cap and subjected to 45 N.m and 57 N.m bending moments. The thickness of the plate is (8 mm), and the diameter of the circular hole is (10 mm). It is intended to replace the aluminium plate with a composite laminate. However, due to new design constrains, the total thickness of the composite plate should not be higher than (4 mm). The material properties of the selected carbon/epoxy laminate are given in Table 1. Assume that 0° and 90° plies do not contribute towards the shear strength of the laminate. Table 1: Material E₁ G12 V12 (GPa) (GPa) (GPa) 181 (GPa) 10.3 7.17 0.28 Figure 1: Aluminium plate properties of the selected carbon/epoxy laminate Ultimate Ultimate S(+45) (MPa) tensile strain 15,500 με compression strain 8.000 με 250 Ply thickness (mm) 0.13 A. Calculate the minimum number of control plies (0°, ±45° and 90°) that can meet the specified design constrains. B. Following the good practise rules for the design of aerospace composite structures, suggest an acceptable laminate stacking sequence. C. Determine the Margin of Safety (M.S.) of the proposed laminate (Part B) for Nx and Ny and discuss the safety issues of the composite plate based on the calculated M.S. values.