水环境对热塑性复合材料层合板分层疲劳裂纹扩展的影响

EFFECT OF WATER ENVIRONMENT ON PROPAGATION OF DELAMINATION FATGUE CRACK IN THERMOPLASTIC COMPOSITE LAMINATES

本文研究了水环境对ＩＣＩＡＰＣ－２热塑性预浸料（ＡＳ４／ＰＥＥＫ）制成的单向复合材料层合板分层疲劳裂纹扩展的影响。用双悬臂梁试件进行了Ｉ型张开位移加载试验。试验环境为２３℃水中和５０℃水中。水环境未引起很大的不利影响。用电子显微镜和机理分析讨论了水环境对ＣＦ／ＰＥＥＫ和ＣＦ／环氧两种层合板的差异。

The effect of water environment on he growth of delamination fatigue cracks wasinvestigated with unidirectional laminates made from ICI APC-2 thermoplastic prepregs(AS4/PEEK).Tests were carried out under mode I opening loading by using doublecantilever beam specimens,the testing environment was water at 23℃and 50℃. Moistureconditioned specimens were also tested in water at 23℃,The water envirnoment did notinduce large detrimental effects,The crack growth rate was expressed as two powerfunctions of the equivalent stress intensity range. The exponent of the power functions in thelow growth rate region was smaller than that in the high growth rate region. lowering thefrequency of stress cycling yielded accelerated crack growth in water,suggesting the time-dependent mechanism of crack growth.The difference of the enviromental effects betweenCF/PEEK and CF/epoxy laminates was discussed on the basis of the fractographicobservation and mechanism consideration.