Papers by Author: Jian Guo Ning

Abstract: A meso-mechanical constitutive model of TiC particle reinforced titanium matrix composites (TiC/TMCs) under impact loading is established to investigate the mechanical behavior of TiC/TMCs. Based on Eshelbys equivalent inclusion theory and Mori-Tanakas concept of average stress in the matrix, the compliance tensor is formulated. By adding nucleation and growth crack models, the influences of micro-cracks on compliance tensor and damage evolution are examined. Finally, a one-dimensional dynamic constitutive model subjected to impact loading is presented to explore the mechanical behavior of TiC/TMCs.

Abstract: A 74-mm-diameter split Hopkinson pressure bar (SHPB) is used to test the dynamic mechanical behavior of concrete and cement mortar. Experimental results show that concrete and cement mortar are rate-dependent. The load-carrying capacity of concrete is higher than that of cement mortar. Whereas, the maximum strain of concrete is lower than that of cement mortar. No matter for concrete or cement mortar, with the increase of impact velocity, the fragment size of specimens after experiment decreases.

Abstract: The high-temperature mechanical behavior of TiC particulate-reinforced titanium matrix composites was investigated at elevated strain rates. The effects of the temperature and strain rate on the mechanical properties of the composites were analyzed. According to Arrhenius flow stress model, a dynamic-high-temperature constitutive relation of TiC particulate-reinforced titanium matrix composites was established.

Abstract: The dynamic compression experiments of reinforced concrete are carried out by one-stage light gas gun apparatus which subjects the reinforced concrete to deformation at strain rates of the order of 104/s with confining pressures of 1~1.5GPa. The stress-strain curves of reinforced concrete with different impact velocities are obtained using Lagrangian analysis method. Experimental results indicate that reinforced concrete is non-linear, rate-sensitive and pressure-dependent.