摘要
结构共振是诱发大型结构件机体振动的常见故障,通常需要通过结构改进以调整固有频率,由于实施难度大,经常采用阻尼方案抑制振动,但并未改变机体结构共振属性。提出一种无需改变机组结构及添加阻尼,仅通过底载调整以改变大型结构件固有频率的技术思路。利用有限元方法建立发电机模型并进行静力学和模态分析,计算不同底载分配状态对结构固有频率的影响。进而开展模拟实验,通过调整发电机机体阶梯形垫片改变其底载分配,并通过振动模态测试获得其结构固有频率。理论分析和实验结果表明:改变底载分配可有效调整大型结构件固有频率,使其避开工作频率,避免结构共振。运用该方法成功解决了秦山二厂发电机机壳结构共振问题。
Structural resonance is one of the common fault types that may induce the large scale structure vibration. Generally, the problem is solved by improving the structure to adjust its of natural frequencies. Due to the difficulty of structural modification, the damping scheme is often used to suppress the vibration. Unfortunately, the resonance property still remains unchanged. In this paper, a new technical thought is proposed, which can change the natural frequencies of the structure by virtue of bottom load adjustment without any structural alteration or extra damping addition. By using the finite element method, the generator model is established and both the static and the modal analyses are carried out. The impacts of different bottom load distribution on the nature frequencies are calculated. Then, the experimental test is conducted. With the stepped gaskets adjusted to change the bottom load distribution, the natural frequencies are obtained through vibration modal testing. Both the theoretical analysis and the experimental results indicate that by altering the bottom load distribution the natural frequencies can be adjusted effectively and kept away from the working frequency such that structural resonance is avoided. This method has been applied for the generator of Qinshan No.2 Nuclear Power Plant, where the problem of structural resonance is successfully solved.
出处
《中国电力》
CSCD
北大核心
2017年第11期33-38,共6页
Electric Power
基金
国家科技重大专项(2014ZX04001051)
国家自然科学基金资助项目(51421004)~~
关键词
发电机
振动
结构
有限元
底载分配
固有频率
generator
vibration
structure
finite element
bottom load distribution
nature frequency
