ABSTRACT Creep behaviour of an epoxy matrix composite with a similar arrangement of composites used in a root joint of a wind turbine blade is investigated in this research. The vacuum infusion process was used to manufacture the composite. Due to the linearity of the viscoelastic behaviour of the composite, the time-temperature superposition principle (TTSP) is applied by using an activation energy shifting method to predict long-term creep behaviour. The activation energy (ΔH) is determined to be 281 kJ mol−1. The calculated shift factor in generating the master curve at the reference temperature of 20°C is 4.75 for a 50°C-creep curve and 7.3 for a 70°C-creep curve. Under operating conditions of the root joint, namely at 20°C/40 MPa, the creep compliance is determined to be 0.63 × 10−12 Pa−1 within 27.8 h (105 s) and increases to 8.6 × 10−12 Pa−1 within 10 years (108.5 s). The creep compliance master curves at 20°C/40, 100 and 300 MPa within 1157 days (108 s) are determined to be 7.1 × 10−12, 12.5 × 10−12 and 18.3 × 10−12 Pa−1, respectively. Scanning electron microscopy examination shows cusps, scarps and pull-out of fibres.

中文翻译：

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E-玻璃/环氧树脂复合材料的长期蠕变行为：时间-温度叠加原理

摘要 在这项研究中，研究了在风力涡轮机叶片根部接头中使用的具有类似复合材料排列的环氧树脂基复合材料的蠕变行为。真空灌注工艺用于制造复合材料。由于复合材料的粘弹性行为的线性，时间-温度叠加原理（TTSP）通过使用活化能转移方法来预测长期蠕变行为。活化能 (ΔH) 确定为 281 kJ mol-1。在 20°C 参考温度下生成主曲线的计算偏移因子对于 50°C 蠕变曲线为 4.75，对于 70°C 蠕变曲线为 7.3。在根部接头的工作条件下，即在 20°C/40 MPa 下，蠕变柔量在 27.8 小时（105 秒）内确定为 0.63 × 10-12 Pa-1，并增加到 8。10 年内（108.5 秒）为 6 × 10−12 Pa−1。1157 天（108 s）内 20°C/40、100 和 300 MPa 的蠕变柔量主曲线分别确定为 7.1 × 10-12、12.5 × 10-12 和 18.3 × 10-12 Pa-1。扫描电子显微镜检查显示纤维的尖端、陡峭和拉出。