Accelerated Life Testing of Structural Polymers Under Cyclic Loading

本研究的目的是开发一种简单可靠的加速寿命测试技术，以预测结构聚合物部件在疲劳载荷条件下的使用寿命。温度、老化时间和溶剂浓度引起的聚合物粘弹性材料功能的转变行为将用于加速疲劳测试。循环加载实验将在高于高温下运行频率的加载频率下进行，以加快时间尺度。将进行两组不同的测试，通过基于自由体积的理论联系起来：（1）在修改的环境条件和更高的负载频率下进行短期加速测试； (2) 长期实验，在很长一段时间内进行，以模拟实际应用中的真实负载条件。将分析和比较这两组实验的结果，以促进可靠的实验寿命测试技术的开发和验证。这项研究的实际意义在于为在变幅疲劳载荷条件下制造或使用聚合物部件的行业提供一种简单的加速寿命测试技术。

The objective of this research is to develop a simple and reliable accelerated life testing technique to predict the service life of structural polymer components under fatigue loading conditions. The temperature, aging time, and solvent concentration induced shift behavior of viscoelastic material functions of polymers will be utilized to accelerate the fatigue tests. Experiments under cyclic loading will be performed under loading frequencies that are higher than in-service frequencies at elevated temperatures to accelerate the time scale. Two different sets of tests, linked by a free volume based theory, will be performed: (1) short term accelerated tests at modified environmental conditions and at higher frequencies in loading; and (2) long term experiments that are conducted over long periods of time to simulate realistic loading conditions in practical applications. The results from these two sets of experiments will be analyzed and compared to facilitate the development of and validation of a reliable experimental life-testing technique. The practical significance of this research will be the provision of a simple accelerated life testing technique for industries that manufacture or use polymer components under variable amplitude fatigue loading conditions.