【摘要】 研究了聚甲基丙烯酸甲酯疲劳裂纹扩展规律。实验结果表明 ,频率增加时 ,疲劳裂纹扩展速率降低 ,试验频率从 0 .1Hz到 2 0 Hz时 ,疲劳裂纹的扩展与频率成幂函数关系 ,而在更高的频率时 ,裂纹尖端出现绝热升温 ,裂尖钝化 ,疲劳裂纹扩展速率明显降低。随着名义平均应力提高 ,由于静断机制的早出现 ,使稳定扩展区变短。试验环境温度的影响 ,可用有机玻璃的β松弛的热激活关系来描述更多还原

【Abstract】 The fatigue mechanical properties of poly(methyl methacrylate)(PMMA) materials were studied. The fatigue crack progression(FCP) rate decreases when frequency increases. When the testing frequency is below 20 Hz, the FCP can be described by the power of the frequency. However, when the frequency is higher than 20 Hz,there will be a higher temperature in the crack tips than in the specimen body. Therefore, the crack become blunt, and the FCP rate decreases much. Under the glass transition temperature, the heat activation energe of the β relaxation can be used to explain the experimental results in different temperatures. At last, an equation is suggested to described the fatigue crack growth rate in the secondary region of the PMMA fatigue crack progression. It can be satisfied with the experimental data.更多还原