外物形状对发动机叶片中残余应力场的影响分析

ANALYSIS FOR EFFECTS OF FOREIGN OBJECT SHAPE ON THE RESIDUAL STRESS FIELD OF ENG INE BLADE

综合运用显、隐式有限元算法对航空发动机叶片进气边受不同形状外物的撞击进行数值分析,在Ansys/LS-DYNA中进行不同形状外物撞击的瞬态显式分析,然后通过显—隐式算法的转换,获得受不同形状的外物撞击后叶片中的残余应力场分布。结果表明,外物的形状对叶片所受的损伤是有影响的,外物撞击部位的形状越尖锐,撞击叶片后叶片中分布的最大残余拉应力值越大,导致叶片的抗疲劳强度受削弱较大;几何外形相近的外物撞击后,叶片中的残余应力场分布趋势相近。

Numerical simulations of foreign objects with different shapes impacting the aeroengine blades were carried out with combined explicit and implicit finite element methods. The explicit dynamic analyses for foreign object damage of blades were performed in Ansys/LS-DYNA. The residual stress fields in the blades after impacting by foreign objects with different shapes were obtained by the explicit-implicit switching method. The results suggest that foreign objects shapes affect the damage of blades. The sharper the foreign object shape is, the bigger the maximum residual stress value in blade after foreign object impacting is. And the fatigue strength of the blade is greatly weakened. The residual stresses in blades which are impacted by foreign objects with similar shapes are distributed approximately.