加捻植物纤维增强树脂基复合材料偏轴拉伸非线性多层次角度融合建模

针对加捻植物纤维增强树脂基复合材料偏轴拉伸非线性力学行为，以宏、细观相结合的思路，建立了融合植物纤维微纤丝角、纱线加捻表面捻转角和复合材料偏轴拉伸角的多层次角度融合本构模型，在实际计算时，由于微纤丝角的随机性、难于测量和对复合材料偏轴拉伸性能相对表面捻转角和偏轴拉伸角的较小影响，假定微纤丝角是常量，计算时仅考虑表面捻转角和偏轴拉伸角，适当简化。最后，利用单向亚麻纤维织物增强环氧树脂基复合材料拉伸实验数据和文献数据验证模型的有效性，模型计算结果与实验结果吻合较好。

Modeling the off-axis tensile nonlinearity of twisted plant fiber reinforced composites fused with hierarchical angles

Aiming at the off-axis tensile nonlinear behavior of twisted plant fiber reinforced composites, hierarchical angle constitutive model was built up by integration of macroscale and microscale methods by considering micro fibril angle of plant fibers, surface twist angle of fiber yarn and off-axis tensile angle of composites. When calculated, this model could only consider the effects of surface twist angle and off-axis tensile angle because micro fibril angle was random, difficult to be measured and less effects to composites' off-axis tensile properties than surface twist angle and off-axis tensile angle. That meant micro fibril angle was assumed to be constant and that model would be simplified. Finally, the model was validated by the experimental data of unidirectional flax fabric reinforced epoxy compo-sites conducted in this research and from the literatures. The calculated results show good agreement with the experimental data.