铝合金板厚度对硼/环氧补片单面修复试件疲劳性能的影响

Thickness effects on fatigue properties of cracked aluminum alloy plate single-side repaired with boron fiber/epoxy patches

采用单向硼/环氧复合材料补片真空袋压工艺单面修复含中心裂纹不同厚度铝合金板,测试了修复试件的疲劳性能,从疲劳寿命、疲劳裂纹扩展速率和裂纹扩展纹线考察不同厚度铝合金板修复后疲劳性能的差异。结果表明:硼/环氧补片胶接修复后,铝合金板的疲劳寿命大幅度提高,且疲劳寿命提高幅度随铝合金板厚度增大而降低。厚度为1.76 mm、5.20 mm和10.20 mm 3种铝合金板修复试件的疲劳寿命分别是未修复试件的22.30倍、12.84倍和8.40倍。厚度为1.76 mm铝合金板修复试件在铝合金板完全断裂后还能继续承担疲劳载荷,而厚度为5.20 mm和10.20 mm 2种铝合金板修复试件在铝合金板断裂后完全破坏。裂纹扩展速率和归一化裂纹长度差均随铝合金板厚度增大而增大。

Using the vacuum bag technique for the patches of boron fiber/epoxy （Be/epoxy） composites, the center - cracked aluminum alloy plates with different thickness were repaired, and then the fatigue properties of the repaired specimens were tested. The fatigue life, crack growth rate and crack growth lag of the repaired specimens were investigated under fatigue loadings. The results show that the fatigue life of the center- cracked aluminum alloy plates is increased by repairing with Br/epoxy patches, and the increment of fatigue life decreases with the increase of the plate thickness. The fatigue life of the repaired specimens with thicknesses of 1. 76 ram, 5. 20 mm and 10.20 mm is 22.30 times, 12.84 times and 8.40 times that of those unrepaired specimens respectively. The repaired specimens with thickness of 1. 76 mm can still bear fatigue loading when the aluminum alloy plate fractured completely, while the repaired specimens with thickness of 5. 20 mm and 10. 20 mm can not do so. Both crack growth rate and normalized crack length difference increase with the increase of the plate thickness.