Experimental and numerical investigation of jet performance based on Johnson-Cook model of liner material

Abstract

A comparative study of the shaped jets of six liner materials, namely, copper, Cu–Zn alloy, Steel1006, high nitrogen steel, and two titanium alloys, was conducted to investigate the influence of the macroscopic mechanical properties of the materials on the jet's performance. The X-ray experiment of the jet was performed, and the numerical calculation of the jet formation was carried out by means of simulation based on the Johnson–Cook model. Copper, Cu–Zn alloy, and Steel1006 formed cohesive jets, whereas the jets of the three other materials had different degrees of radial dispersion. The penetration depth of the jet has a significant negative correlation with its radial dispersion degree. In the numerical calculation, the head shape of the jet under the Euler algorithm can be used to judge its cohesion. Arrowheads or rounded oval heads symbolize cohesive jets, whereas blunt or even mouth-forward “bowl-shaped” heads indicate jets with radial dispersion. The degree of dispersion is positively correlated with the degree of dullness of the jet head. Simulation results show that the influence of material melting temperature and thermal softening effect on jet velocity, length, and diameter is particularly evident, whereas the influence ability of yield strength and strain rate effect is always at a very low level. Materials with small shear modulus, high yield strength, and significant strain effects are more prone to forming non-cohesive jets, which was verified by the jet forming experiments of amorphous alloy with these material characteristics.