The effect of fiber orientation on progressive failure of composite plates / Zaharuddin Muhammad

The objective of this thesis is to analyze the effect of fiber orientation on progressive failure of composite plates. A mathematical model and computational model are presented for the analysis. Higher Order Shear Deformation Theory is utilized to predict the deformation of the plates. A failure criterion with the existence of coupling terms to determine the mode of failure for composite plates is employed to predict the failure. The selection of this criterion is made because of its uniqueness that it includes the coupling terms, which relate the interaction between the longitudinal stress and the transverse stresses. A program based on a finite element method is utilized by using Fortran-90 to determine the lamina stresses. These stresses are then used in the present failure model to determine the First Ply Failure and Last Ply Failure. From the analysis, it is found that the fiber orientation affected the progressive failure of the composite plates. Fiber orientation due to different lay-up will give different progressive failure load to constitute First Ply Failure and Last Ply Failure of the plates. From the results, we found that the best lay-up for this orientation is (0/45/45/0). The analysis has been proved by comparing the results of failure curves. In conclusion the objective of this research is successfully achieved. Perhaps in future, this thesis can offer better prediction of failure to engineers and designers in their designing work of composite structures.