航空发动机外物损伤试验技术研究

国外对发动机外物损伤都有规范要求。美国军标MIL-E-5007D发动机通用规范要求:“发动机吸入外物后,外物对风扇、压气机工作叶片和静子叶片造成最小应力集中系数(k_t)为3的损坏时发动机应还能工作到型号规范规定的两个检查周期或小时数。”从而明确规定了考验发动机外物损伤的试验条件和合格标准。我国据79、80两年空军不完全统计,外物击伤发动机多达70起,远远超过鸟撞次数。这些击伤发动机的外物有小的螺钉、螺帽、开口销,还有布块、饭盒、皮帽、指挥旗等。因此在我国制定的“涡喷、涡扇发动机通用规范”GJB241-87中,对外物损伤也有明确的试验要求,试验条件和合格标准与美军标MIL-E-5007D一致。 

EXPERIMENTAL TECHNIQUE FOR INVESTIGATION ON FOREIGN OBJECT DAMAGE OF AEROENGINE

A method to determine the size of notch on first stage blade of compressor with a stress concentrated factor (K t) of three is briefly introduced,which is required for foreign object damage (FOD)testing of aeroengines.It is based on 8-node and 20-node finite element appoaches respectively.The 8-node super-parameter element approach is used to calculate the stress distribution of a whole blade without and with notch,and the 20-node 3D iso-parameter finite element programm is applied to computation of local stress distribution around a notch of blade.The practical testing techniques and test results are also presented.