Abstract
In this paper an experimental study is carried out to characterise the shear response of carbon fibre reinforced epoxy laminates. While maintaining an essentially linear response in longitudinal and transverse directions, it is shown that this material displays significant non-linear shear stress-strain behaviour to rupture and that it is not possible to model this with existing closed form constitutive models, such as the Hahn-Tsai model. A novel damage model is derived where the non-linear shear behaviour is captured using a cubic spline interpolation method. The model can capture the non-linear stress-strain behaviour, including the damage progression and the rupture response. Hashin"s failure criteria are used to predict damage in the laminates and this is incorporated within the framework of the material model. The model is three-dimensional and is implemented into the ABAQUS finite element code using the UMAT user defined material subroutine. The cubic spline equations are linearised, thus allowing them to be written in incremental form and so easily implemented into UMAT. The material Jacobian matrix is fully defined, thus allowing a full implicit material model to be derived. Hence, the model is suitable for both implicit and explicit codes. It is shown that the model accurately predicts the response of the laminates under longitudinal, transverse and shear loadings. The paper will present both the experimental and numerical findings and give the complete derivation of the damage model.
Original language | English |
---|---|
Title of host publication | Proceedings of the 9th International Conference on Computational Structures Technology, CST 2008 |
Publisher | Civil-Comp Press |
Volume | 88 |
ISBN (Print) | 9781905088232 |
Publication status | Published - 2008 |
Event | 9th International Conference on Computational Structures Technology, CST 2008 - Athens, Greece Duration: 2 Sep 2008 → 5 Sep 2008 |
Conference
Conference | 9th International Conference on Computational Structures Technology, CST 2008 |
---|---|
Country/Territory | Greece |
City | Athens |
Period | 2/09/08 → 5/09/08 |
Keywords
- Composites
- Constitutive modelling
- Finite element analysis
- Material damage
- Non-linear shear