Materials and their development process are highly dependent on proper experimental testing under wide range of loading within which high-strain rate conditions play a very significant role. For such dynamic loading Split Hopkinson Pressure Bar (SHPB) is widely used for investigating the dynamic behavior of various materials. The presented paper is focused on the SHPB impulse measurement process using experimental and numerical methods. One of the main problems occurring during tests are oscillations recorded by the strain gauges which adversely affect results. Thus, it is desired to obtain the peak shape in the incident bar of SHPB as “smooth” as possible without any distortions. Such impulse characteristics can be achieved using several shaping techniques, e.g. by placing a special shaper between two bars, which in fact was performed by the authors experimentally and subsequently was validated using computational methods.

A method of tensile testing of materials in dynamic conditions based on a slightly modified compressive split Hopkinson bar system using a shoulder is described in this paper. The main goal was to solve, with the use of numerical modelling, the problem of wave disturbance resulting from application of a shoulder, as well as the problem of selecting a specimen geometry that enables to study the phenomenon of high strain-rate failure in tension. It is shown that, in order to prevent any interference of disturbance with the required strain signals at a given recording moment, the positions of the strain gages on the bars have to be correctly chosen for a given experimental setup. Besides, it is demonstrated that - on the basis of simplified numerical analysis - an appropriate gage length and diameter of a material specimen for failure testing in tension can be estimated.

Two types of composites, consisting of pure magnesium matrix reinforced with two commercially used carbon fibers, were systematically studied in this paper. The composites fabricated by the pressure infiltration method, were subjected to quasistatic and dynamic compression tests. Morphology of fiber strands was observed using scanning electron microscope (SEM). The application of carbon fibre reinforcement led to the stiffening of tested materials, resulting in the limitation of the possible compression to approx. 2.5%. The performed tests revealed the remarkable difference in compression strength of investigated compositions. The cause of that effect was that GRANOC fiber reinforced composite exhibited insufficient bond quality between the brittle fibers and the ductile matrix. T300 reinforced composite presented good connection between reinforcement and matrix resulting in increased mechanical properties. Investigated composites demonstrated higher mechanical strength during deformation at high strain rates. Microscopic observations also proved that the latter fibers with regular shape and dense packaging within the filaments are proper reinforcement when designing the lightweight composite material.

As the dynamic behavior of the concrete is different from that under static load, this research focuses on the study of dynamic responses of concrete by simulating the split Hopkinson pressure bar (SHPB) test. Finite element code LS-DYNA is used for modeling the dynamic behaviors of concrete. Three continuous models are reviewed and the Holmquist-Johnson-Cook model (HJC) is introduced in detail. The HJC model which has been implemented in LS-DYNA is used to represent the concrete properties. The SHPB test model is established and a few stress waves are applied to the incident bar to simulate the dynamic concrete behaviors. The stress-strain curves are obtained. The stress distributions are analyzed. The crack initiation and propagation process are described. It is concluded that: the HJC model can modeling the entire process of the fracture initiation and fragmentation; the compressive of the concrete is significantly influenced by the strain rates.