A composite has 20 vol% fibres with Ef = 150 GPa in a matrix Em = 30 GPa. If subjected to load parallel to the fibre direction, the fibre would fail first when the stress of fibre reaches 22.5 GPa....

Extracted text: A composite has 20 vol% fibres with Ef = 150 GPa in a matrix Em = 30 GPa. If subjected to load parallel to the fibre direction, the fibre would fail first when the stress of fibre reaches 22.5 GPa. Note the composite stress is expressed as o̟ = Vf0s, + (1-Vf) omfı. The matrix would fail later at a failure strain of 0.4, where the composite stress is expressed as a, = (1 – V;)ơm- Assume both the matrix and the fibres deform elastically and subsequently undergo brittle fracture. What would be the maximum stress the composite can withstand? 8.1 GPa 4.5 GPa 12 GPa 22.5 GPa 9.6 GPa