بررسی اثر نرخ کرنش در ورق های دایروی تحت بارگذاری دینامیکی با معرفی نسبت واماندگی دینامیکی به استاتیکی

  Abstract   In this paper, the effect of strain rate sensitivity of materials in the case of a fully clamped circular plate has been discussed introducing a new criterion called "dynamic to static collapse pressure ratio". In order to do so, a simple mass and wire model is assumed. Then, using Cowper-Symonds constitutive relation and Perrone-Bhadra Simplifications, the mean strain rate of such a plate has been calculated. Experiments have been conducted on 5010 Aluminium and St37 Plates which were subjected to underwater explosion. According to the maximum deflection of each plate and the absorbed energy which is calculated by means of Duffey empirical relation, the dynamic to static collapse pressure of the plate is figured. Results showed that by increasing the strain rate, the average dynamic yield stresses of St37 and AA5010 plates are increased 2.3 and 1.5 times relative to their static yield stresses.