摘要
螺栓松动损伤具有非线性特征,在低、高频激励共同作用下,结构动力响应会出现高频激励与结构固有频率之间的调制现象。利用该调制现象,发展了一种基于经验模式分解(EMD)的螺栓松动检测方法,分别对高频正弦和随机激励下结构响应信号进行EMD分解并作功率谱分析,采用EMD分解后含有调制成分的高频固有模式函数(IMF)构造能量损伤指标来识别结构螺栓松动。采用多尺度法进行单自由度非线性模型分析解释高频调制现象,并通过螺栓连接框架结构的振动实验验证了该方法的有效性。结果表明,螺栓松动时,响应信号频域中出现高频激励与固有频率间的调制成分,所构造的能量损伤指标能够有效识别螺栓松动损伤,并且对于初始松动损伤识别更为敏感。
Boh looseness is a nonlinear damage that would result in modulation between excitation frequency and natural frequencies by a combination of low- and high-frequency excitations. Using the vibration modulation, this paper developed a vibration-based method for detecting bolt looseness based on empirical mode decomposition （EMD）. The response signal was analyzed for nonlinear modulation in frequency domain. Then, using the high-frequency intrinsic mode functions that contain the frequency-modulation component based on EMD, an effective energy-based damage index was established to detect the presence of the nonlinear damage with the analysis of energy distribution. A four-story frame structure vibration test was carried out to investigate the feasibility of the method. The result of the experiment demonstrates that modulation occurs in the high-frequency component of response signals; the proposed energy-based damage index can be used to accurately detect nonlinear damage caused by bolt looseness and is sensitive to early structural damage
出处
《振动与冲击》
EI
CSCD
北大核心
2016年第8期201-206,共6页
Journal of Vibration and Shock
基金
国家自然科学基金资助(51078293
51378402)
关键词
螺栓松动
损伤识别
经验模式分解
能量损伤指标
调制
bolt looseness
damage detection
empirical mode decomposition
energy damage index
modulation
