Material constitutive behavior identification at high strain rates using a direct-impact Hopkinson device

Xiaoli Guo (1) , Cheikh-Tidiane Sow (1) , Chady Khalil (1) , Thomas Heuzé (1) , Guillaume Racineux (1)

1 GeM - Institut de Recherche en Génie Civil et Mécanique

Modern numerical simulation techniques allow nowadays obtaining accurate solutions of magnetic pulse and electrohydraulic forming/welding processes. However, one major difficulty persists: the identification of material constitutive equations behavior at levels of high strain rates reached by these processes, and which varies between 10³ and 10⁵s^-1. To address this challenge, a direct-impact Hopkinson system was developed at ECN. It permits to perform dynamic tests at very high strain rates exceeding the range of the traditional Split Hopkinson Pressure Bars and hence enable us to identify constitutive models for a wide range of strain rates. The alloy used to test this device was Ti-6Al-4V. Strain rates up to 2.5×10³s^-1 were attained.

Mots clés: Direct impact Kolsky bar; inverse analysis; high strain rate; elastic-viscoplastic; constitutive models

Domaines: Mécanique des matériaux [physics.class-ph]

Xiaoli Guo, Cheikh-Tidiane Sow, Chady Khalil, Thomas Heuzé, Guillaume Racineux. Material constitutive behavior identification at high strain rates using a direct-impact Hopkinson device. 7th International Conference on High Speed Forming (ICHSF), Apr 2016, Dortmund, Germany. ⟨hal-02279968⟩