2 Mark.docx

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4.A failure envelope is a three-dimensional plot of the combinations of the normal and shear stresses that can be applied to an angle lamina just before failure. 5. After fiber failure, the load carrying capacity of composite is dependent on the following condition

The volume fraction of fibers for which this is possible is called minimum fiber volume fraction It is also possible that, by adding fibers to the matrix, the composite will have lower ultimate tensile strength than the matrix. In that case, the fiber volume fraction for which this is possible is called the critical fiber volume fraction, (Vf)critical 6. Failure is predicted in a lamina, if any of the normal or shear stresses in the local axes of a lamina is equal to or exceeds the corresponding ultimate strengths of the unidirectional lamina. Failure is predicted in a lamina, if any of the normal or shearing strains in the local axes of a lamina equal or exceed the corresponding ultimate strains of the unidirectional lamina. 7.

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In laminates that are not symmetric, a temperature difference results in out-of-plane deformations. This deformation is also called warpage. 9. laminate stacking sequence , fiber , matrix properties , fiber volume volume fraction , interfacial bonding 10. face: aluminum alloy and fiber reinforced plastics such as graphite/epoxy and glass /epoxy Core:balsa ,foams such as polyuretherane , phenolic and polystyrene , honeycomb structure