Analysis of fiber waviness in laminated composites subjected to compressive loads
The competence of composite materials to supersede the use of metals and traditional materials has made it a preferred application in the field of structural engineering, aviation, automobiles, etc. An insightful research into the evaluation mechanical properties and behavior of the material under different loading conditions enables an improved design of the structure. The evaluation of different types of defects in a composite material has been a key area of research in the recent years. In structural analysis, the fiber waviness in laminate layers is often ignored and ideal properties of straight fibers are assumed. These properties are generally lower and non-conservative as the strength and stiffness are lower than that predicted for straight fiber composites. In this thesis, the compressive behavior of a composite cross ply laminate with fiber waviness is investigated. The reduction in the mechanical properties such as stiffness and strength is studied with the help of analytical equations and finite element modeling. First, an analytical model is developed to predict the reduction in the stiffness for a cross ply laminate. The equations in the model are solved in Maple software. The finite element analysis is then carried out on ABAQUS software to study the effect of waviness on the stress distributions and the loss of strength for a laminate with fiber waviness. The results obtained from various experiments are used to validate the analytical models and the finite element results under similar conditions.
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering