基于冲压试验的聚乙烯力学性能预测

Prediction of mechanical properties of polyethylene based on punch tests

通过对5种不同曲率半径的高密度聚乙烯(PE-HD)圆棒试样进行单轴拉伸试验,重点分析了曲率半径对工程应力-位移曲线的影响;同时对PE-HD平板试样进行冲压试验,分析了压头直径和冲压速度对载荷-位移曲线的影响;建立了3种基于冲压载荷预测PE-HD单轴屈服应力的经验公式。结果表明,同一拉伸速度下,屈服强度随曲率半径的减小而增大;同一冲压速度下,最大冲压载荷随压头直径的增大而增大;同一压头直径下,最大冲压载荷随冲压速度的增大而增大;基于压头直径为变量的经验公式预测得到的屈服强度可靠性最高,可以较为准确地表征PE-HD的力学性能。

In this paper,monotonic tensile tests were first conducted using five high-density polyethylene(PE-HD)round bar specimens with different notch radii to study the effects of notch radius on the curves of engineering stress-displacement curves.Moreover,punch tests were also conducted on the PE-HD plate specimens to investigate the load-displacement curves with an indenter diameter and a punch speed.Finally,three empirical equations for the prediction of yield stress of PE-HD materials based on characteristic punch load were proposed.The results indicated that the yield stress obtained from the monotonic tensile tests increased with a decrease in notch radius at the same loading speed.Additionally,the maximum punch load increased with an increase in the indenter diameter or punch speed.The predicted yield stress based on the empirical equation is closest to the tensile test result when using the indenter diameter as variable.