The effect of strain rate, temperature, and molecular mass on the tensile deformation of polyethylene
The effect of strain rate, temperature, and molecular mass on the tensile deformation of polyethylene
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DOI：
10.1002/pen.11180
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发表时间：
2000-02
影响因子：
3.2
通讯作者：
S. Hillmansen;S. Hobeika;R. N. Haward;P. Leevers
中科院分区：
文献类型：
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作者：
S. Hillmansen;S. Hobeika;R. N. Haward;P. Leevers
应用于高密度聚乙烯的常规拉伸试验可能由于样品横截面的局部减小而导致材料拉伸响应的错误印象。一些工作人员已经开发了新的拉伸测试技术来测量小元件变形时的响应。所得到的真实应力-真实应变曲线以几何无关的方式描述了材料的拉伸变形。在这里，从以前的工作人员的结果，加上我们自己的一些，被解释的哈沃德-萨克雷弹簧阻尼模型，其中弹簧定义的应变硬化过程中根据高弹性理论和阻尼描述了一个应变无关的粘性过程。温度，应变速率，和分子质量对每个过程的影响进行了研究。对于管道级，改性的高密度乙烯共聚物，已经测量了足够的数据来解释应变速率和温度的影响，根据Eyring流动过程，其中两种机制的参数被发现是相似的。
Conventional tensile testing applied to high density polyethylene can lead to erroneous impressions of the tensile response of the material due to a local reduction in cross section of the sample. Several workers have developed novel tensile testing techniques to measure the response of a small element as it deforms. The true stress true strain curve that results describes tensile deformation of the material in a geometry-independent manner. Here, results from previous workers, together with some of our own, are interpreted in terms of the Haward-Thackray spring-dashpot model, in which the spring defines a strain hardening process according to the theories of high elasticity and the dashpot describes a strain-independent viscous process. The effects that temperature, strain rate, and molecular mass have on each process are investigated. For a pipe-grade, modified high density ethylene copolymer, sufficient data have been measured to interpret the effects of strain rate and temperature in accordance with an Eyring flow process, where the parameters for the two mechanisms are found to be similar.