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某型发动机喷管在装机飞行时出现的小裂纹可能会引发严重的飞行事故。为了避免飞行事故的发生,基于有限元仿真技术,针对该型发动机喷管结构,建立计算模型。并对某喷管整体结构进行了自由振动和模态分析,获得了该喷管模型的多阶自振频率和模态。结果表明:分析值与实测值吻合较好。其中,在20阶振动频率之前,共振造成的破坏主要集中于前转接段,20阶以后,共振造成的破坏转移到喷管的端口位置。所得结果对于结构改进和避免事故的发生具有一定的参考价值和指导意义。
A small crack in a type of engine nozzle that occurs during a flight may cause a serious flight accident. In order to avoid the occurrence of flight accident, a finite element simulation technology is proposed to calculate the nozzle structure of the engine. The whole structure of a nozzle was subjected to free vibration and modal analysis, and the multi-order natural frequency and mode of the nozzle were obtained. The results show that the analytical value is in good agreement with the measured value. Among them, before the 20-order vibration frequency, the damage caused by the resonance is mainly concentrated in the front transfer section. After the 20th order, the damage caused by the resonance is transferred to the port position of the nozzle. The results obtained for the structural improvement and avoid accidents have a certain reference value and guiding significance.