碳纤维拉索抗冲击防护材料动态拉伸性能的试验研究

Experimental study on dynamic tensile properties of impact protection materials of CFRP cables

为明确高密度聚乙烯(PE-HD)、聚氨酯(PU)和三元乙丙橡胶(EPDM)这3种材料在不同应变速率下的拉伸性能,对其轴向拉伸性能进行了试验研究,得到了不同应变速率下各材料的应力-应变曲线。结果表明,PE-HD具有较好的延性,拉伸过程中产生了较大塑性变形,而PU属于弹性材料,相较之下,EPDM在拉伸过程中产生的可恢复变形具有明显时间相关性,属于黏弹性材料;随着应变速率的增大,PE-HD的屈服强度与拉伸模量显著提高,但屈服强度对应的应变却降低,当应变速率从0.01 s^(-1)提高至1.0 s^(-1)时,其屈服强度与拉伸模量分别提高23.4%和40.4%;应变速率对PU的拉伸模量和断裂伸长率影响较大,但应变速率对其拉伸强度的影响较小,与应变速率为0.01 s^(-1)时的拉伸模量与断裂伸长率相比,应变速率为1.0 s^(-1)时的拉伸模量增加了39.1%,但断裂伸长率降低了55.2%;随着应变速率的增大,EPDM的拉伸强度与拉伸模量提高,而其断裂伸长率却随之减小,当应变速率由0.01 s^(-1)提高至1.0 s^(-1)时,其拉伸强度与拉伸模量增幅分别为19.9%和16.5%。

To investigate the tensile properties of PE-HD,PU and EPDM,axial tensile tests were conducted to obtain their stress-strain curves at different strain rates.The results indicated that PE-HD exhibited favorable ductility with large plastic deformation during the tests,whereas PU presented an elastic nature.On the other hand,EPDM as a type of viscoelastic material showed an evident time-dependency of deformation recovery performance.The yield strength and tensile modulus of PE-HD increased significantly with an increase in strain rate but its strain at yield strength decreased.PE-HD obtained an increase in yield strength by 23.4%and in tensile modulus by 40.4%when the strain rate increased from 0.01 s^(-1)to 1.0 s^(-1).The tensile modulus and elongation at break of PU were significantly influenced by strain rate;however,there was little influence of strain rate on its tensile strength.Compared to the tensile modulus and elongation at break obtained at a strain rate of 0.01 s^(-1),PU exhibited an increase in tensile modulus by 39.1%but a decrease in elongation at break by 55.2%at a strain rate of 1.0 s^(-1).With increasing the strain rate,the tensile strength and tensile modulus of EPDM increased but its elongation at break decreased.When the strain rate increased from 0.01 s^(-1)to 1.0 s^(-1),the tensile strength and tensile modulus of EPDM increased by 19.9%and 16.5%,respectively.