碳纤维复合材料假脚冲击后的疲劳试验

Fatigue Experiment of Carbon Fiber Composites Prosthetic Foot after Impact

针对一种新型结构的碳纤维复合材料假脚,开展了自由落体冲击试验及冲击后疲劳寿命试验,分析了不同铺层参数、不同冲击能量等因素对其冲击损伤及疲劳寿命的影响规律。结果表明,不同铺层参数对碳纤维复合材料假脚U形结构件的冲击损伤具有显著影响,且随着0°铺层含量的降低,试件的冲击损伤面积增加,外观损伤越来越严重;碳纤维复合材料结构件的疲劳性能对冲击能量比较敏感,随着冲击能量的增加,碳纤维结构件的冲击损伤面积明显增大,其疲劳寿命逐渐降低。在冲击能量从4J增加到10J的情况下,碳纤维复合材料假脚的疲劳寿命大幅度降低了66.8%;尽管随着冲击能量的增加,试件的疲劳寿命逐渐降低,但二者之间并不符合线性关系,即冲击能量存在一门槛值,当冲击能量超过该门槛值后,其对碳纤维结构件疲劳寿命的影响将减弱;仅当碳纤维复合材料假脚的后龙骨厚度为2.7mm,且冲击能量≤4J的情况下,其疲劳寿命才可较好地满足相关安全标准的要求。

Experiment studies on drop-weight impact and fatigue life were performed for a novel carbon fiber composites prosthetic foot. The influences of layer parameter and impact energy on the impact damage and fatigue life of the carbon fiber composites prosthetic foot were analyzed. Results show that, layer parameter has significant influence on the impact damage of U-type component of carbon fiber composites prosthetic foot. With the decrease of 0° layer content, the impact damage area gradually reduces, and surface damage is becoming serious. The fatigue properties of carbon fiber composites are susceptible to the impact energy. With the increase of impact energy, the impact damage area of U-type component increases and fatigue life decreases. On the condition of the impact energy increasing from 4J to 10J, the fatigue life of the carbon fiber composites prosthetic foot drops dramatically by 66.8%. Although the fatigue life deduces with the increasing impact energy, both of them are not of linear relationship. A threshold exists for the impact energy. As the impact energy is higher than the threshold, the influence of impact energy on fatigue life of carbon fiber composites will be weakened. The U-type component with the thickness of 2.7mm and the impact energy less than 4J are necessary conditions for the fatigue life of the carbon fiber composites prosthetic foot, being satisfied with the safety standard.