Find modulus of elasticity of the composite under isostrain:
A composite is made of alternate layers of 60% E-glass and 40% epoxy resin. If modulii of elasticity of E-glass and epoxy are respectively 72 GPa and 3 GPa, find modulus of elasticity of the laminated composite under isostrain and isostress conditions. Illustrate loading on sketch.
(a) Isostrain : Estrain = V f E f + Vm Em
= 0.6 × 72 + 0.4 × 3
= 44.4 GPa
(b) Isostress : Estress = E f Em / VfEm+ VmEf = E f / Vf + Vm(Ef/Em)
= 72 / (0.6 + 0.4 × (72/3) = 7.06 GPa