Thermal fracture of plastics
Thermal fracture of plastics
复制标题
塑料的热断裂
DOI：
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发表时间：
1973
期刊：
影响因子：
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通讯作者：
R. N. Haward
中科院分区：
文献类型：
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作者：
A. Cross;R. N. Haward
本文研究了不同长度的聚氯乙烯带材在拉伸下的拉伸和断裂。有人发现，尽管应变速率降低，长件受到一种类型的脆性断裂（颈缩断裂）发生后立即颈部形成。这个结果，这可以从以前的工作中预期，被证明取决于存储在较长的测试件的弹性能量。这种能量在颈部形成的条件下转化为热量，导致温度上升24 ± 4°C，由热成像系统确定。对于短试样，温度上升要小得多，并且发生向稳定颈部扩展的过渡。光学和电子显微照片提供了断裂表面加热的额外证据。绝热过程的半定量处理给出了忽略热损失的预测温度变化的上限和下限。还可以估计绝热变形开始的最小长度。这两种计算都给出了与实验合理一致的结果。对聚碳酸酯的观察表明，在低温下也有类似的长度效应。
The extension and fracture under tension of poly(vinyl chloride) strips of different lengths have been studied. It was found that, in spite of decreasing strain rate, long pieces are subject to a type of brittle fracture (necking rupture) occurring immediately after neck formation. This result, which could be expected from previous work, is shown to depend on the elastic energy stored in the longer test pieces. This energy is converted to heat under conditions of neck formation, leading to a temperature rise of 24 ± 4°C, determined by a thermal imaging system. With short test pieces the rise in temperature is much smaller, and a transition to stable neck propagation occurs. Optical and electron micrographs provide additional evidence of heating at the fracture surface. A semiquantitative treatment of the adiabatic process gives upper and lower limits for the predicted temperature change neglecting thermal losses. It is also possible to estimate a minimum length for the initiation of adiabatic deformation. Both calculations give results in reasonable agreement with experiments. Observations with polycarbonate show a similar length effect at low temperatures.