The fatigue behaviour of a biaxial carbon/epoxy Non-Crimp-Fabric (NCF) composite is evaluated at room temperature and 130^o C for automotive applications. A new specimen geometry is developed allowing three stress ratios R = 0.1, R = −1 and R = 10 to be tested at 130^o C without the use of anti-buckling fixtures for axial loadings. The three stress ratios show good agreement in fatigue life using an equivalent stress amplitude. The fracture surfaces from failed fatigue test specimens are compared to those of monotonic loading to evaluate the changes to failure modes under the different loading conditions. Tensile dominated loading such as uniaxial tension and fatigue testing with R = 0.1 result in delamination of the NCF material coupled with fibre failure along the loading direction as the primary failure modes. Compressive fatigue failures at 130 °C occur at an inclined angle through thickness due to a shearing process along with fibre kinking. The matrix material exhibits more ductile characteristics at 130^o C altering the fracture surfaces at elevated temperature.

在汽车应用中，在室温和130 ^o C下评估了双轴碳/环氧树脂非卷曲织物（NCF）复合材料的疲劳性能。开发了一种新的试样几何形状，可以在130 ^o下测试三个应力比R = 0.1，R = -1和R = 10C不使用抗屈曲夹具进行轴向载荷。使用相同的应力振幅，这三个应力比在疲劳寿命中显示出良好的一致性。将疲劳失效试样的断裂表面与单调加载的断裂表面进行比较，以评估在不同加载条件下失效模式的变化。拉伸为主的载荷（如R = 0.1的单轴拉伸和疲劳测试）会导致NCF材料分层以及沿着载荷方向的纤维断裂，这是主要的失效模式。由于剪切过程以及纤维扭结，在整个厚度倾斜的角度下，在130°C时会发生压缩疲劳破坏。基体材料在130 ^o C时表现出更大的延展性，从而在高温下改变了断裂表面。