The assessment of thermal fatigue behaviors of thin-walled structures with holes is a challenging task. A novel experimental approach was designed to test the thermal fatigue behaviors of thin-walled structures with holes. The experiments were conducted under three test conditions (300–850/950/1000 ℃) to investigate the behaviors of crack initiation and early propagation. The cyclic temperature loading exhibits high-transient and wide-ranging characteristics, enabling the construction of a non-uniform transient temperature field in the heating step. A thermal fatigue phase field model was developed for elastoplastic solids, and thermal fatigue fracture modeling and life prediction were performed. The phase field effectively reproduces crack morphology, and the experimental results closely match the simulation results when fatigue parameters are properly selected. Raising the upper limit of temperature will significantly diminish thermal fatigue life, accelerate crack growth, and induce a broader range of material damage. The temperature gradient in the heating step enhances the cyclic plastic behavior at the edge of the hole, significantly amplifying the detrimental impact of thermal fatigue.

中文翻译：

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带孔薄壁结构的热疲劳行为：实验和相场断裂建模

带孔薄壁结构的热疲劳行为评估是一项具有挑战性的任务。设计了一种新颖的实验方法来测试带孔薄壁结构的热疲劳行为。实验在三种测试条件（300–850/950/1000 ℃）下进行，以研究裂纹萌生和早期扩展的行为。循环温度加载表现出高瞬态和宽范围的特性，使得能够在加热步骤中构建非均匀的瞬态温度场。开发了弹塑性固体的热疲劳相场模型，并进行了热疲劳断裂建模和寿命预测。相场有效地再现了裂纹形貌，并且当疲劳参数选择正确时，实验结果与模拟结果非常吻合。提高温度上限将显着缩短热疲劳寿命，加速裂纹扩展，并引发更广泛的材料损坏。加热步骤中的温度梯度增强了孔边缘的循环塑性行为，显着放大了热疲劳的有害影响。