Further investigation on the dynamic compressive strength enhancement of concrete-like materials based on split Hopkinson pressure bar tests Part II Numerical Simulations

Q.M. Li , Y.B. Lu , H. Meng

Split Hopkinson pressure bars (SHPB) have been used widely to measure the dynamic compressive strength of concrete-like materials at high strain-rate between 10 and 10 s. It has been shown in companion paper (Zhang et al. 2009) that the axial strain acceleration is normally unavoidable in an SHPB test on brittle materials. Axial strain acceleration introduces radial confinement in the SHPB specimens and consequently enhances the compressive strength of concrete-like specimens. This paper employs numerical simulation to further demonstrate that the unexpected radial confinement in an SHPB test is responsible for the increase of the dynamic compressive strength of concrete-like materials at strain rates from 10 to 10 s. It confirms the observations in Zhang et al. (2009) that the dynamic increase factor (DIF) measured in SHPB tests can be reduced either by using tubular SHPB specimens or by reducing the diameter of the SHPB specimen. A kinetic friction model is proposed based on kinetic friction tests and is implemented in the numerical model. It shows that it is necessary to use a kinetic friction model, rather than a constant friction model, for more accurate numerical simulation of SHPB tests.

Mots clés: concrete-like materials; split Hopkinson pressure bar; dynamic increase factor; compressive strength; kinetic friction model; numerical simulation

Q.M. Li, Y.B. Lu, H. Meng. Further investigation on the dynamic compressive strength enhancement of concrete-like materials based on split Hopkinson pressure bar tests Part II Numerical Simulations. International Journal of Impact Engineering, 2009, 36 (12), pp.1335. ⟨10.1016/j.ijimpeng.2009.04.010⟩. ⟨hal-00618189⟩