【摘要】 采用线性关系式及多项式对爆炸膨胀环速度曲线上不同长度的数据窗口进行拟合,获得了应力应变关系,结果表明数据窗口的选取是膨胀环实验数据处理的基础;同时发现当拟合关系式高于2次时,获得的应力应变关系从形式上偏离了物理规律。对数据进行高阶光滑后采用差分方法直接处理,可以更好地反映膨胀环速度历史与瞬时应力之间的关系,澄清了2次以上关系式拟合处理得到的应力应变关系偏离物理规律并不是由数据处理方法造成的,而是由速度点测试的不确定性造成的。更多还原

【Abstract】 The movement of a freely expanding ring was analyzed and the radial velocity-time curve of the expanding OFHC copper ring was experimentally obtained by the laser interference technique.The different data windows were chosen from the obtained velocity-time curve and the intercepted data in the different windows were fitted by different methods.Then the accelerations were acquired from the differential equations of the velocities.The stress-strain curves were gained by processing the velocities of the ring under one-dimensional stress assumption.Results show that the reasonable selection of data windows is the correct data-processing foundation for expanding ring tests.While the ranks of fitting expressions are higher than 2,the obtained stress-strain relation will lapse formally from physics rules.But after the data,which are smoothed by higher-rank expressions,are processed by the direct difference method,the processed data can reflect better the relationship between the velocity history of the expanding ring and its instantaneous stresses.It explains that the lapse of the above fitted stress-strain relation from physics rules does not result from the data processing methods but from the uncertainty of the velocity measurement at one point.更多还原