Material model for distortional hardening of unidirectional CFRTP considered from the results of virtual material testing.

Macroscopic stress-strain curves of composite material made by embedding the uni-directed carbon fiber in the epoxy resin are measured by means of virtual material testing based on homogenization theory. These results indicate that the material has unique mechanical properties for the strain hardening effect. However, the material behaviors cannot express even for conventional material models which are incorporated not only simple isotropic or kinematic hardening but also combined or distortional hardening law.

The initial yield surface adopted in this study is made by the combination of multiple functions in accordance with the Bimodal plasticity theory proposed by Dvorak et al.. Particularly, in our novel material model, only one specific function among them is hardened. Thanks to this property, it has been confirmed that the hardened yield surface is in good agreement with the measured results of virtual material testing.

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1. Introduction
2. Material model of uni-directed CFRTP
3. Virtual experimentation
4. Results
5. Conclusions
6. Additional references

Figure: FE model for microstructure of uni-directed CFRTP