Failure Prediction of Carbon-Epoxy Composite Laminates using Finite Element Analysis

Abstract

Continuous growth in the use of fibre reinforced polymer composites in advanced structural applications, such as aerospace, marine, and automotive are observed in past two decades. Composite materials offer numerous advantages when compared to conventional materials available in manufacturing industries. A significant decrease in mass, increase in strength and stiffness are some of these advantages. Additionally the ply orientation can be preferably tailored to the loading conditions, so the laminates have desired stiffness, ability to form complex shapes and durability. The key objective of this research is to evaluate the accuracy and predictive capabilities of finite element models and failure modelling of composite materials using the ABAQUS software. A set of unidirectional and multidirectional composite laminatesmade of carbon-epoxy (IM7/977-3) has been selected. The numerical simulations are carried out by using the Hashin’s failure criterion. The use of failure criteria assists in predicting four different failure modes, such as matrix tensile failure, fibre tensile failure, matrix compressive failure, and fibre compressive failure. The development of damage is monitored with continuous loading for the different cases. The numerically simulated results are compared against carefully conducted experimental data shared by US Air Force Research Laboratory (AFRL). Unidirectional (0-degree) composite laminates tested under tensile and compressive loading shows a difference of 10.5% and 17.7% in maximum principal stress, respectively. The unidirectional composites under transverse loading (90 degree) show a difference of 10.8% and 0.4% under tensile and compressive loading, respectively. The cross-ply composite laminates under tensile loading show a maximum difference of 20.6% between the model and experimental results for the layup configuration [0,45,90,-45]2S. A minimum difference of 3.5% is observed in the composite developed of [60,0,-60]3S layups. Cross ply laminates tested under compressive loading show a maximum difference of 14.7% in [60,0,-60]3S, and a minimum difference of 4.6% in [0,+45,90,-45]2S composite laminates. It was found that the Hashin’s criterion fails to predict the experimental results for composites with an open hole accurately, as the difference observed is 25.3% and 23.7%, respectively, under tensile and compressive loading. The variations in the experimental and modelled results are mainly due to considering and analysing the model in its 2D behaviour, which excludes delamination. Additionally, composite laminates tested under compressive loading suffers from Brooming Gage Bottom (BGB). Hence, the Hashin’s damage model is not a good candidate when the delamination is expected as a dominant failure mode. This work will lead to the development of a well-validated computational tool to predict deformation and failure behaviour of a range of composite materials. As a result, this modelling tool can be used for the prediction of structural integrity and durability of various critical components used in the aerospace, mining, marine and automotive industries.