Cohesiveness and penetration performance of jet: Theoretical, numerical, and experimental studies

•A new jet forming criterion is proposed by using the pressure relationship.•Proportion of non-cohesive segment in jets can be predicted using the proposed model.•Non-cohesive jet penetrates steel target much less effectively than a cohesive jet.•Non-cohesive jet penetrates into concrete significantly improve the damage efficiency.•Jets with radially discrete particles is a means to achieve high damage efficiency. Jet formation was studied by performing theoretical analyses and numerical calculations, and a predictive model was proposed. X-ray experiments were conducted to verify the model and investigate the jet formation. Static penetration experiments were performed to study the penetration ability, and the microscopic topography of the penetration channel was observed to reveal the potential effect of jet cohesiveness on the penetration performance. The results showed that the proposed model can predict jet formation and help determine the proportion of non-cohesive segment of the jet. Because of the coexistence of cohesive and non-cohesive segments in the actual jet, determining an exact proportion of non-cohesive segment is beneficial for selecting the penetration model and improving calculation accuracy. In the theoretical model, pressure was considered as the main factor and the use of the collapse angle, which is difficult to measure accurately, was avoided, thereby effectively improving the engineering practicability of the model. The results of the penetration experiments showed that the radial dispersion of particles can weaken the axial penetration ability significantly but improve the damage efficiency (crater, hole, and caving). At a suitable stand-off, the non-cohesive jet can improve the damage efficiency and maintain a good penetration depth when penetrating the concrete. The results of this study provide new ideas for jet formation research and a reference for the development of high-damage warheads.