不同应变率下聚乙烯材料的压缩力学性能

为了研究聚乙烯材料在不同应变率下的压缩力学性能，通过准静态实验和动态实验获得聚乙烯材料不同应变率下的应力应变曲线，分析发现:聚乙烯的弹性模量和屈服强度随应变率增大而增大，具有明显的黏弹塑性；聚乙烯材料进入塑性阶段，其应力应变曲线在不同应变率下具有相近的变化趋势，即塑性切向模量近似相同。根据聚乙烯材料的压缩力学性能，建立了弹性区、屈服点和塑性区的分段本构模型。该模型的屈服点和塑性段与实验结果吻合较好，由于弹性段采用线弹性模型，与实验结果存在一定偏差，可近似描述材料的弹性行为。

Compressive mechanical properties of polyethylene at different strain rates

In this work, we studied the compressive mechanical properties of polyethylene at different strain rates and obtained the stress-strain curves of polyethylene at different strain rates using static and dynamic experiments. We analyzed the stress-strain curves of polyethylene and discovered that the elastic modulus and the yield strength of polyethylene increase with the increase of the strain rate, and polyethylene has obvious viscoelasticity. The stress-strain curves have similar trends at different strain rates after polyethylene enters the plastic stage. We established a constitutive model of elastic zone, yield point and plastic zone according to compressive mechanical properties of polyethylene. The yield point and the plastic section of the model are in good agreement with the experimental results. As the elastic section adopts the linear elastic model, a certain deviation from the experimental results was observed, which can approximately describe the elastic behavior of the material.