复合材料层压板疲劳特性的试验研究

EXPERIMENTAL STUDY ON FATIGUE BEHAVIOUR OF COMPOSITE LAMINATE

<正> 1.引言 最初人们认为复合材料对疲劳载荷不敏感,因为它们在拉一拉载荷下对应干10~7次循环的疲劳强度与静强度十分接近,显示了极其优越的抗疲劳性能。但进一步的研究却发现,与一般的金属材料不同,复合材料对以压为主的疲劳载荷比较敏感,在这些载荷下的寿命明显地低于拉-拉疲劳载荷下的寿命。因此,复合材料的疲劳问题重新受到了注意,而且对它的研究也主要集中在压缩载荷的范围内。尽管已投入了大量的人力。

Fatigce tests with smooth and notched specimens of T300/QY8911 composite are performed under constant amplitude fatigue loading(R =-1), and two S-N curves are obtained. Spectrum fatigue tests are also conducted for the notched specimens. The test results are compared with the predicted results using Miner' s theory and Brout-ma's linear residual strength degradation model. It is found that both Miner's theory and the linear residual strength degradation model are to overestimate the fatigue life, and for the present cases the prediction from the linear residual strength degradation model is better than that from Miner's theory. In addition, the test method was also described in detail.