Literature review on imperfection of composite laminated plates

tA composite material can be defined as a combination of two or more materials that givesbetter properties than those of the individual components used alone In contrast to metal lic alloys each material retains its separate chemical physical and mechanical properties The two constituents are reinforcement and a matrix The main advantages of compositematerials are their high strength and stiffness combined with low density when comparedto classical materials Micromechanical approach is found to be more suitable for the anal ysis of composite materials because it studies the volume proportions of the constituentsfor the desired lamina stiffness and strength It is found that the manufacturing processes are responsible of many defects which mayarise in fibers matrix and lamina These defects if they exist include misalignment of fibers cracks in matrix non uniform distribution of the fibers in the matrix voids in fibers andmatrix delaminated regions and initial stress in the lamina as a result of its manufactureand further treatment The above mentioned defects tend to propagate as the lamina is loaded causing an accel erated rate of failure The experimental and theoretical results in this case tend to differ Hence due to the limitations necessary in the idealization of the lamina components theproperties estimated should be proved experimentally