Abstract: In this paper, dynamical calculation and analysis are made on penetration of thin plates by truncated conical projectiles in terms of the needs of fuze designing. The impact velocity ranges from 200w/s ts to 1000m/s (including both low and high velocities). The target plates include the thin aluminium plate (metal) and the plywood (non-metal).Because a strength effect of target plates is considered in the establishment of dynamical models, we solved the problem that some previous models were not suitable to lowvelocity impact, for example, M. Zaid and B. Paul’s models [1][2][3] Bv comparison of menial effect with strength effect, we theoretically proved Zaid and Paul’s experimental conclusion131: "Only when the impact velocity is more that 500m/s can the strength effect be neglected. Otherwise this effect can not be neglected".

Key words: crack, dynamic stress intensity factor, weight function method, three-point bending specimen, loading rate