Abstract
The usage of composites has increased in various fields, including automotive and aerospace, due to their high strength-to-weight ratio. The optimum use of composite material is also being studied to bring down the fuel costs and carbon emissions to atmosphere. The concept of optimum usage of composite material could be applied at the initial design stage or when repairing damaged composite structures. This paper describes preliminary work towards the optimum usage of π/4 quasi-isotropic E-glass/epoxy laminate repair practices, and it demonstrates the procedure followed to determine their tensile properties. This work used unidirectional fibre (UDF) laminae and UDF laminate specimens to understand the tensile properties of UDF E-glass/epoxy laminate. This paper provides a unique comparison between experimental results of UDF laminae and UDF laminate level. The tensile properties obtained from UDF laminae and UDF laminate were suitably used to derive [A][B][D] matrices of π/4 quasi-isotropic laminates, so as to understand whether the laminates were pertaining to the quasi-isotropic category. Finally, π/4 quasi-isotropic laminates with the above-mentioned codes were tested to understand the tensile properties. The derived properties could be suitably used for future work on quasi-isotropic E-glass/epoxy composite laminate repair practices.