The use of plasticine to simulate the dynamic compression of prismatic blocks of hot metal
The use of plasticine to simulate the dynamic compression of prismatic blocks of hot metal
复制标题
使用橡皮泥模拟铁水棱柱块的动态压缩
DOI：
10.1016/0020-7403(67)90051-3
复制
发表时间：
1967
影响因子：
7.3
通讯作者：
W. Johnson
中科院分区：
文献类型：
--
作者：
S. Aku;R. Slater;W. Johnson
在室温下使用白色橡皮泥作为模型材料来研究铁水的动态压缩。具有圆形、方形、矩形、三角形和环形截面的标称高度为 1 英寸的样品，使用模型落锤在室温下的光滑压板之间以平均应变率高达 200 秒−1 进行动态压缩。对于三棱柱和空心圆柱体，使用了粗糙的压板。该材料的准静态真应力-自然应变曲线表现出很小的应变硬化，直至自然应变约为 1·0。对于室温下的不同截面，平均动态屈服应力 Y m 与平均应变率之间的关系显示为 Y m= B 的形式。按照作者分析结果的方式，下落质量的增加似乎会导致恒定应变速率下平均动态屈服应力的增加。对于等边三棱柱块和空心圆柱体，平均动态法向压力随着样品与毛坯压板之间摩擦系数的增加而明显增加。变形能/单位体积 E V 与自然应变 ε 之间的关系表现为 E V= C εm 形式的幂律。对于给定的能量/单位体积，随着质量的增加获得更大的变形。镦粗轴对称样本在所有缩减量中都或多或少保持轴对称性，但即使高度缩减量超过 70%，空心圆柱体的孔也不会闭合，无论样本是否润滑良好。在立方体、矩形和三棱柱的情况下观察到不均匀的横向扩展，但正方形和矩形的形状变化即使减少高达70%也不明显。当减少量超过 70% 时，三角形截面的棱柱往往会变成圆形。缩小 87% 后，三角形截面几乎变成直径为 2 英寸的完整圆形。进一步的定性实验表明，即使轴对称样本保持近似轴对称，在润滑良好的样本动态压缩期间，在压缩率超过约 0.5 时，也会遇到显着的不均匀变形。
White plasticine was used as a model material at room temperature to study the dynamic compression of hot metals. Specimens of 1 in. nominal height having circular, square, rectangular, triangular and annular sections were subjected to dynamic compression at mean strain-rates up to 200 sec− 1 between smooth platens at room temperature using a model drop-hammer. Rough platens were used in the cases of the triangular prisms and hollow cylinders. The quasi-static true stress-natural strain curve for the material exhibited little strain hardening up to a natural strain of about 1· 0. The relation between the mean dynamic yield stress, Y m, and the mean strain-rate,, is shown to be of the form Y m= B for different sections at room temperature. Following the manner in which the authors analyse their results, an increase in the falling mass appears to cause an increase in the mean dynamic yield stress at constant strain-rate. An increase in the mean dynamic normal pressure was apparent with increase in the coefficient of friction between a specimen and rough platens for equilateral triangular prismatic blocks and hollow cylinders. The relation between deformation energy/unit volume, E V, and natural strain, ε, is shown to be a power law of the form E V= C εm. Greater deformation for a given energy/unit volume is obtained with increase in mass. Upset axi-symmetrical specimens remain more or less axi-symmetric for all reductions, but the holes of the hollow cylinders do not close even with height reductions exceeding 70 per cent, regardless of whether or not the specimens are well lubricated. Non-uniform lateral spread is observed in the case of the cubes, rectangular and triangular prisms, but the change in shape of the squares and rectangles is not appreciable even for reductions up to 70 per cent. The prisms of the triangular section tend to become circular for reductions greater than 70 per cent. At a reduction of 87 per cent the triangular section becomes almost a complete circle of 2 in. diameter. Further qualitative experiments indicate that significant inhomogeneous deformation is encountered during dynamic compression of well lubricated specimens at fractional reductions exceeding about 0.5, even though axi-symmetric specimens remain approximately axi-symmetric.