全湿热场下碳纤维/环氧树脂复合材料层间剪切强度

Interlaminar Shear Strength of Carbon Fiber/Epoxy Composites Under Hygrothermal Conditions

针对T700/TR1219B碳纤维/环氧树脂复合材料,在不同湿/热/力耦合条件下进行层间剪切实验,对比分析性能衰减规律,通过峰值力纳米力学模量成像技术定量表征界面尺寸变化,并结合微观断口形貌分析探究湿热损伤机制。结果表明,T700/TR1219B的层间剪切性能受湿、热场影响显著,当吸湿率为2%时,层间剪切强度从原样的72.64 MPa下降到46.92 MPa;随温度的升高,层间剪切性能呈线性递减趋势,降幅约为0.35 MPa/℃;高温高湿环境下层间剪切强度最大降幅达到93%,且温度场造成的损伤效应高于湿度场。微观表征结果表明,吸湿作用是导致界面尺寸增大的主要因素,而高温高湿环境会对纤维、树脂及其界面均造成明显损伤。通过对比分析湿、热单一和耦合作用下T700/TR1219B层间剪切强度的变化规律,建立了全湿热场下层间剪切强度模型。

The interlaminar shear strength(ILSS)test of carbon fiber/epoxy T700/TR1219 B composites was conducted under different hygrothermal conditions.The degradation mechanism was investigated by fracture morphologies and the change of interphase size characterized by peak force quantitative nano-mechanics technique.The experiment results show that ILSS changes significantly in hygrothermal environment.The ILSS decreases from 72.64 MPa to 46.92 MPa with the moisture absorption rate of 2%.The ILSS exhibits a linear decreasing trend with 0.35 MPa/℃when the test temperature varies from 20℃to 180℃.The coupled moisture-temperature condition results in a fall of 93%at most in ILSS,mainly caused by the resin degradation under high temperature.The interphase characterization and morphology results show that moisture is the main factor leading to the increase of interphase size,and the coupled moisture-temperature conditions cause significant damage to fiber,resin and the interphase.The residual strength model was established concerning the effects of moisture,temperature and coupled moisture-temperature conditions.