Experimental characterization and constitutive modeling of the non-linear stress–strain behavior of unidirectional carbon–epoxy under high strain rate loading

• Main Authors: Hannes Koerber, Peter Kuhn, Marina Ploeckl, Fermin Otero, Paul-William Gerbaud, Raimund Rolfes, Pedro P. Camanho
• Format: Article
• Language: English
• Published: SpringerOpen 2018-06-01
• Series: Advanced Modeling and Simulation in Engineering Sciences
• Subjects: Composites; Carbon–epoxy; Strain rate effects; Viscoplasticity; Constitutive modeling
• Online Access: http://link.springer.com/article/10.1186/s40323-018-0111-x

Abstract The mechanical response of IM7-8552 carbon epoxy was investigated for transverse tension and transverse tension/in-plane shear loadings at static and dynamic strain rates using transverse tension and off-axis tension specimens. The dynamic tests were carried out on a split-Hopkinson tension bar at axial strain rates from 113 to 300 $$\hbox {s}^{-1}$$ s-1 . With the already available off-axis and transverse compression test data for IM7-8552, a comprehensive data set is available now, which can be used for validation and calibration of numerical models. The measured axial stress–strain response was simulated using a fully 3D transversely isotropic elastic–viscoplastic constitutive model. The constitutive model represents a viscoplastic extension of the transversely-isotropic plasticity model developed by the authors (Vogler et al. in Mech Mater 59:50–64, 2013). An invariant based failure criterion is added to the model to be able to predict the strength for a given orientation and strain rate accurately. The strain rate dependency of the elastic and ultimate strength properties is introduced in the model through scaling functions. A good correlation between the measured and numerically predicted stress–strain response and failure of the specimens was achieved for all specimen types and both strain rate regimes.