Unidirectional reinforced composites

1. Calculating the mechanical properties of unidirectionally reinforced composites Choose one combination of fibre and matrix from the list below (According to your Surname Initials) and investigate quantitatively the range of strength and modulus that could be obtained using unidirectional short and continuous fibre reinforcement. You should assume that all combinations conform to a brittle fibre model.

PART 2 : Analysis of Laminates

2. A composite consists ofVf(by volume) continuous, uniaxially aligned glass fibres in a matrix of epoxy resin. Select Vr which is matching your Surname initials. The tensile modulus and Poisson's ratio for the glass and the epoxy are 76 GPa and 0.22 and 2.4 GPa and 0.34, respectively. A tensile stress of 150 MPa is applied at 30° to the fibre direction as shown below:

Calculate the reduced plane-stress stiffness matrix, [Q], for the lamina and hence determine the matrix for the stress and strain components in the x-y co-ordinate system, [Q"]. Invert this matrix to obtain the compliance and hence determine the strains in the x-x, y-y and x-y directions resulting from the app lication of the stress.

Note: Relationship between elastic moduli for isotropic materials (applicable to matrix and fibre properties):

Shear modulus:Bulk modulus: