加载速率对缺口前应力、应变分布的影响

Influence of loading rate on stress and strain distribution a notchs in front of in notched specimen

用动态有限元法,计算了一种低合金钢在不同加载速率下四点弯曲缺口试样缺口根部应力、应变和应变率的分布.结果表明:缺口前各点的应变率和试样整体屈服载荷Pgy随加载速率的增加而增加;在相同的P/Pgy下,缺口前各点的正应力随加载速率的增加而增加,而应变基本不变.加载速率对缺口前应力、应变分布的影响是由于其引起了缺口前应变率的变化,从而使材料力学性能发生变化所引起的.

The distributions of stress, strain and strain rate in front of a notchtip in four point bending specimens with various loading rate are calculated with the dynamic explicit finite element method. It has been found that the strain rate in front of notchtip and the general yield load Pgy increase with loading rate. At the same P/Pgy the normal stress increases with loading rate, but the strain does not vary essentially. The influence of loading rate on stress and strain distribution in front of notchtip is resulted from the variation of the mechanical properties of material due to the variation of strain rate which is, in turn, caused by various loading rate.