基于有限元法的风洞结构故障诊断

针对2.4m风洞第一扩散段在运行过程中出现的裂纹现象,应用振动测试技术和有限元分析方法,进行了不同工况条件下振动测量和脉动压力测量,获得了结构在气流脉动压力作用下的主要振动频率范围。通过与有限元分析结果验证对比,诊断出了第一扩散段产生裂纹的原因在于内壳体裂纹板与气流长期耦合振动,结构疲劳从而导致出现裂纹。最后在此基础上提出了合理的整改方案,对结构进行了动力学修改。结果表明：结合振动测试,基于有限元法对风洞结构进行故障诊断是一种行之有效的方法。

Fault diagnosis of the wind tunnel structure based on finite element method

Aimed at the crack phenomena appeared in the running process of the first diffuser of 2.4m wind tunnel,the vibration and pulsant pressure measurements on the different operating conditions were carried out with vibration test technology and finite elemnet method,and the range of mostly vibration frequency has been obtained.Comparing with the results of finite element analysis,the reason of crack on the first diffusion has been diagnosed that the lasting coupling vibration between the inner shell body and the airflow fatigued the structure,thus caused the crack failure.Finally,the modification scheme was proposed,and the structural dynamics modification was carried out.These results show that the method for fault diagnosis of wind tunnel structure based on finite element method and vibration test is effective.