On the longitudinal compressive strength prediction of unidirectional laminated composites based on an improved model

The compressive failure of unidirectional (UD) composite laminates is investigated using an improved model. Most of the existing models to predict the compressive strength of UD composites are either based on microbuckling or kinking of fibers. However, the failure mechanism analysis based on the SEM microscopy observations of failed specimens shows that the two mechanisms are responsible for the failure simultaneously when kinking occurs following the microbuckling of fibers. Therefore, the fiber microbuckling and fiber kinking models are combined to predict the compressive strength of UD T300/QY8911 composite laminate. Furthermore, this study proposes a new model for the stiffness of the foundation determination, making the predicted microbuckling strength closer to its real value. Also the effects of parameters presented in the prediction formula on the compressive strength are discussed, and it is found that the Young's modulus of matrix is the most important parameter. The predicted compressive strength using the improved model with combined modes shows a very good agreement with the experiment measurement. POLYM. COMPOS.