不同金属硬物冲击航空发动机叶片损伤研究

Study on damage of aero-engine blades caused by different metal hard materials

为分析不同金属硬物对航空发动机风扇叶片造成的外物损伤特征差异,选取钢、铜、铝、铅四种材料弹珠作为外来物,以两种角度、多种速度冲击真实叶片进气边缘进行高速弹道冲击试验,并采用数值方法仿真动态损伤过程。结果表明:钢、铜珠冲击时,叶片损伤形貌可分为凹坑、撕裂和缺口,产生撕裂形貌时,小角度相比于大角度冲击需要更高的冲击速度,铜珠相比于钢珠冲击需要更高的速度;铝、铅珠因冲击时自身变形较大,对叶片只能造成挤压变形。仿真结果表明:在2.2J冲击能量条件下,铜珠、钢珠造成叶片撕裂损伤的过程中存在两个显著的接触力峰值,且伴随着"动能回升"现象;铜珠动能较多地转化为叶片和自身的应变能,因而对叶片的侵彻能力不如钢珠;铝珠冲击力峰值最大,其动能转化为自身应变能的比例最高;铅珠冲击力峰值不明显,其动能大部分转化为摩擦耗散的热量。

In order to analyze the characteristics difference of foreign object damage caused by different metal hard materials on the aero-engine fan blades,beads made of steel,copper,aluminum and lead were regarded as foreign objects,the intake edges of real blades were impacted at two angles and different speeds,and the dynamic damage process was simulated by numerical methods.The experiment results showed that when the steel and copper beads impacted,the blade damage morphology could be divided into pits,tears and gaps,when the tearing appearance occurred,the small angle impact required higher speed compared with large angle impact.Furthermore,copper beads impact required higher speed compared with steel beads impact;aluminum beads and lead beads had large deformation when they were impacted,which only caused extrusion deformation of the blade.The simulation results showed that,when the impact energy was 2.2 J,there were two significant peaks of contact force in the process of tear damage caused by copper beads and steel beads,accompanied by the phenomenon of"kinetic energy recovery";more kinetic energy of the copper bead was transformed into the blade and its own strain energy,so its penetration ability to the blade was not as good as that of the steel bead;the aluminum bead had the highest impact force,and the ratio of its kinetic energy to its own strain energy was the highest;the impact force peak of the lead bead was not obvious,and most of its kinetic energy was converted into heat consumed by friction.