Nonlinear analysis of thick composites with fiber waviness under flexural loading

A FEA(Finite Element Analysis) model was developed to predict the nonlinear behavior and to study stress and strain distributions in thick composites with fiber waviness under flexural loading. In the analytical model, both material and geometrical nonlinearities were incorporated into the model using energy density, iterative mapping and incremental method. Three types of fiber waviness model were considered in this study: uniform, graded and localized fiber waviness models. A special fabrication technique was developed to produce thick composite specimens with various degrees of uniform fiber waviness. Four-point bending tests were conducted to obtain the nonlinear behavior of thick composites with fiber waviness. It was found that the predictions from the model were in good agreement with the experimental results and the nonlinear behavior as well as local stress and strain distributions of composites were significantly affected by both the type and degree of fiber waviness.