Research of an SHPB Device in Two-by-Two Form for Impact Experiments of Concrete-Like Heterogeneous Materials

A split Hopkinson pressure bar (SHPB) device in two-by-two form, including the bar bundle form and the single cylindrical bar form, was designed in response to the demand for the dynamic mechanical experiments for brittle materials such as concrete, rock, etc. The stress waveforms generated through a projectile impacting two different types of incident bars have been studied based on the one-dimensional stress wave theory and numerical simulation method. At last, based on the established two types of mesoscale concrete models with random convex polyhedral aggregates, we performed comparison analysis of SHPB numerical simulations for concrete materials with bar bundle and single cylindrical bar separately, so as to provide technical support for the manufacture and development of this experimental device. The results showed that the introduced two-by-two form SHPB device expanded the scope of practical application, and the wave dispersion effect existing in a large-diameter bar can be evidently reduced when we employed the bar bundle form, indicating its applicability to the dynamic mechanical experiments of concrete-like heterogeneous materials.