This paper aims to experimentally and numerically explore fracture mechanism characteristics of ultra-thin chopped carbon fiber tape-reinforced thermoplastics (UT-CTT) hat-shaped hollow beam under transverse static and impact loadings. Three distinct failure modes were observed in the impact bending tests, whereas only one similar progressive collapse mode was observed in the transverse bending tests. The numerical model was to incorporate some hypothetical inter-layers in UT-CTT and assign them with the failure model as cohesive zone model, which can perform non-linear characteristics with failure criterion for representing delamination failure. The dynamic material parameters for the impact model were theoretically predicted with consideration of strain-rate dependency. It shows that the proposed modeling approach for interacting damage modes can serve as a benchmark for modeling damage coupling in composite materials.

    Abstract
    1 Introduction
    2 Experimental investigation
        2.1 Sample preparation
        2.2 Testing procedure
    3 Numerical investigation
        3.1 Theoretical prediction for dynamic mechanical properties
        3.2 FEM under three-point bending
        3.3 FEM under impact loading
    4 Results and discussion
        4.1 Three-point bending
        4.2 Impact loading
    5 Concluding remarks
    Acknowledgements 
    References

• Qitao Guo(Department of Systems Innovation, School of Engineering, The University of Tokyo)
• Bohan Xiao(Department of Systems Innovation, School of Engineering, The University of Tokyo)
• Isamu Ohsawa(Department of Systems Innovation, School of Engineering, The University of Tokyo)
• Jun Takahashi(Department of Systems Innovation, School of Engineering, The University of Tokyo)