13th International Conference on Fracture June 16–21, 2013, Beijing, China -16- We used combined experiment-numerical method to obtain failure locus in the equivalent failure strain and stress triaxiality space respectively under static loading and dynamic loading. There is significant difference between static loading and dynamic loading, which indicates strain rate impacts greatly on failure locus of the polymeric materials we studied. We utilized two failure predictive techniques to identify failure locus, trying to obtain accurate result. Under dynamic loading, average stress triaxiality method is enough determine failure locus in each type of test. While under static loading, damage evolution rule should be used to optimize the fracture locus since stress triaxiality varies greatly during the loading process especially for shear test. 10. References [1] T. Wierzbicki, Y. Bao, Y. W. Lee, Y. Bai, Calibration and evaluation of seven fracture models. International Journal of Mechanical Sciences, 2005, 47: 719-743. [2] Y. Bai, T. Wierzbicki, Application of extended Mohr-Coulomb criterion to ductile fracture. International Journal of Fracture, 2010, 161: 1-20. [3] Y. Bao, T. Wierzbicki, On fracture locus in the equivalent strain and stress triaxiality space. International Journal of Mechanical Sciences, 2004, 46: 81-98. [4] S. Kolling, A. Haufe, M. Feucht & P.A. Du Bois, SAMP-1: A Semi-Analytical Model for the Simulation of Polymers, Anwenderforum, Bamberg 2005. [5] Y. Bao, Prediction of Ductile Crack Formulation in Uncracked Bodies. MIT PHD thesis, 2003. [6] H. Mae, Characterization of Material Ductility of PP/EPR/talc Blend under Wide Range of Stress Triaxiality at Intermediate and High strain Rates. Journal of Applied Polymer Science, 2009, 111: 854-868. [7] ASTM D638M, Standard test method for tensile properties of plastics, 1993. [8] H. Daiyan, E. Andreassen, F. Grytten, H. Osnes, R.H. Gaarder, Shear testing of polypropylene materials analysed by digital image correlation and numerical simulations. Experimental Mechanics, 2012, DOI 10.1007/s11340-012-9591-7. [9] ASTM D5379, Standard Test Method for Shear Properties of Composite Materials by the VNotched Beam Method, 1993. [10]ASTM D3763-95a, Standard Test Method for High Speed Puncture Properties of Plastics Using Load and Displacement Sensors, 1993. Acknowledgements The authors would like to thank General Motor R&D for the support on Project Testing and Modeling of Polymeric Materials for Crash Safety CAE. Thanks also to Foundation of Zhejiang Province Automobile Safety Technology Laboratory.
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