在分离式Hopkinson拉杆实验中确定临界实验条件的经验方法

在分离式Hopkinson拉杆实验中，常常需要获得试样在经历一个拉力脉冲拉断情况下的最低应变率，而在分离式Hopkinson拉杆装置中确定对应最低应变率的发射压力需要进行多次尝试性实验。为了更好地解决这一问题，提出一种简单的经验方法，可以通过一次拉断的实验结果计算出一个拉力脉冲拉断试样需要的最小发射压力及相应的应变率，进一步可以预测不同发射压力下的应变率。对4种铝合金试样进行拉伸实验，结果表明，利用提出的经验方法得到的应变率结果与实验结果吻合较好，可以有效地对发射压力和实验应变率进行预估。
In split Hopkinson tensile bar test, it is necessary to obtain the smallest strain rate of the specimen which was fractured by a tensile stress impulse, while determining the corresponding launch pressure of the smallest strain rate needs to conduct many tentative tests. In order to solve this problem well, an empirical method which needs to carry out tensile fracture test only once was proposed to calculate the smallest launch pressure and strain rate to fracture the specimen. The method can further predict the strain rate in different launch pressure. The tensile fracture tests of four kinds of aluminum alloy testify that the proposed method is coincident with the experimental results and it is efficient to evaluate the launch pressure and strain rate.