Experimental and Numerical Study on the Mechanical Properties of Alumina Ceramics Based on a Modified SHPB Setup

In response to the high stiffness and hardness levels of alumina ceramic materials, the traditional SHPB (split Hopkinson pressure bar) experimental setup has been modified. This study analyzes the propagation patterns of stress waves in the SHPB system after adding cushion blocks. Experiments demonstrated that the modified SHPB apparatus can effectively perform dynamic mechanical property tests on alumina ceramics. The JH-2 constitutive damage model parameters for alumina ceramics were determined based on theoretical analysis and static/dynamic experimental data. An LS-DYNA numerical model for the impact compression simulation of alumina ceramics was established to investigate the effects of stress waves with three wavelengths (300 mm, 400 mm, and 600 mm) at the same impact velocity, along with the dynamic fragmentation process. The results indicate that alumina ceramics exhibit strain rate hardening effects in compressive strength, failure strain, and elastic modulus under high strain rates; compressive strength and failure strain show positive correlations with stress wave wavelength under high strain rates; and microcracks initially nucleate preferentially along grain boundaries on the end surfaces, forming annular damage zones symmetrically about the central axis. This study presents a modified SHPB setup that improves test capability for high-hardness ceramics, rather than overturning classical methodologies. The absence of a direct comparison with unmodified setups stems from the known limitations of conventional systems in handling small-diameter alumina specimens without bar damage—a challenge addressed proactively in this work through impedance-matched cushion blocks and refined data processing.