Virtual durability testing of CFRP materials

Abstract

The demand for products made from carbon fibre reinforced polymers (CFRP) is rapidly increasing. As in the car industry where there is a need for more lightweight and energy efficient solutions to lower the environmental effects. The new Polestar 1 car is an example where CFRP has been introduced in several parts of the car body. When usage increases, it also becomes more important to understand the properties of the material. To lower the costs of material tests, this project has developed a test methodology detailing the way to perform virtual material tests at Volvo Cars. The first part of the project covers unidirectional (UD) plies which are stacked together into laminates with fibre orientations at different angles. A 3D physically based constitutive material model, called LaRC05 which was developed by Pinho, Iannucci, and Robinson (2006a), is used in the project. This model proved to be one of the more accurate material models during the second World Wide Failure Exercise (Kaddour and Hinton, 2013). Later in the project, a strategy to model more complex fibre architectures and to transform the model into different test environments is proposed. The developed methodology reduces the number of physical laminate tests and shows good correlation towards physical tests in room temperature environment. It can predict the strength at first sign of failure and models the same failure mode that can be seen in physical tests. Further work has to be performed on how to predict failure in hot and wet test environments. For cold environments it is recommended to look closer on compression tests while tension tests show a good correlation. Weak areas of the methodology are discussed together with possible actions of improvement.