船载雷达随机振动疲劳寿命分析

Fatigue life prediction of shipborne radar based on random vibration analysis

振动疲劳作为结构破坏失效形式之一,正日益得到重视。传统的船载雷达设备设计往往仅考虑静强度,从而导致结构抵抗疲劳破坏的能力不足。从模态分析的角度入手,利用模态叠加法进行随机振动分析,得到结构的各向应力功率谱密度。在此基础上进行基于VonMises应力的谱分析,并分别从宽带和窄带过程的角度进行了疲劳寿命估算,最后对某船载雷达进行了随机振动疲劳分析。结果表明,船载雷达结构在满足静强度条件下,不一定能够满足抗疲劳性能要求。从模态振型分析的角度改进了结构设计,分析验证表明,改进后结构能够满足随机振动疲劳寿命要求。

As one of the failure forms of structure, vibration fatigue is getting more and more attention. However, the traditional design of shipborne radar only considers the static strength, which leads to the lack of the ability to resist fatigue damage. From the perspective of modal analysis, this paper uses modal superposition method for random vibration analysis, so as to obtain the power spectral density of structural stress in all directions. On this basis, the spectrum analysis based on Von Mises stress is carried out, and the fatigue life is estimated from the perspective of broadband and narrowband processes respectively.Finally, the random vibration fatigue analysis of a shipborne radar is carried out. The results show that the structure of shipborne radar can not meet the requirements of anti fatigue performance under the condition of static strength. Then, from the perspective of modal analysis, the structural design is improved. Finally, through the analysis, it is concluded that the improved structure can meet the requirements of random vibration fatigue life.