On the transition from interface defeat to penetration in the impact of long rod onto ceramic targets

•Three deformation modes of the long rod and the ceramic target are summarized.•The critical impact velocity range for the transition is further identified.•Critical transition time is analyzed and an analytical expression is formulated.•The analytical formula is convenient for the engineering application.

Based on the related research on the penetration of long rod into ceramic targets, the present manuscript summarizes qualitatively three deformation modes of the rod and target under different impact velocities: interface defeat, normal penetration and transition from interface defeat to penetration. Then the phenomenon of transition is investigated in detail. Firstly, integrated with the analysis on the mechanical property of ceramic material, the critical impact velocity range within which the transition phenomenon occurs, i.e., the highest impact velocity corresponding to interface defeat and the lowest impact velocity corresponding to normal penetration, is further identified. Subsequently, the critical transition time from interface defeat to penetration is discussed, in which the detailed damage and failure characteristics of ceramic material during the interface defeat process are taken into account. Finally an explicit half-analytical expression of the critical transition time is formulated.