应用桥联模型预测复合材料吸湿老化剩余强度

采用试验与理论相结合的方法, 研究了玻璃纤维/环氧树脂复合材料的吸湿老化剩余强度, 测试了基体的吸湿性能, 对老化前后基体、 纤维及其复合材料的拉伸性能进行了试验研究。根据纤维和基体性能测试数据, 应用桥联模型计算了复合材料的吸湿老化剩余强度, 计算结果与试验结果一致。结果显示: 在小吸湿率条件下, 利用桥联模型能够准确预测复合材料的破坏演化规律及其最大剩余强度。当主承力层破坏由纤维控制时, 由湿老化引起的纤维强度的下降直接导致复合材料最大拉伸强度的下降; 当破坏由基体控制时, 影响复合材料吸湿剩余强度的主要因素是基体硬化及强度的下降。较小吸湿率对纤维与基体的界面粘结强度影响有限, 界面破坏不是层合板破坏的主要因素。 

Residual strength prediction of composites with after moisture absorption using bridging model

The residual strength of glass fiber/epoxy composites after immersion aging in water was studied. The water absorption property of resin and the tensile properties of resin, fiber and composites were tested after and before aging in water. Based on the test, the residual strength of the glass fiber/epoxy composites after water immersion aging was calculated using a bridging model. The numerical results indicate that the theoretical values calculated by the method are well fitted with the test results. The results show that the model could be used to accurately predict the progressing damage regulation and the strength under the condition of low water absorption ratio. When the main bearing layers damage are controlled by fiber, the descending of fiber tensile strength caused by water immersion directly results in the descending of the composites maximum tensile strength. The major factor on the residual strength of composites is resin harden and tensile strength decreasing caused by water immersion to the layers controlled by resin. The effect of the low water absorption ratio on the strength of the interface of fiber and resin is finite.