【摘要】 悬臂梁结构是小阻尼系统,模态阻尼对裂纹故障敏感,为了解决传统阻尼识别方法识别误差大的问题,创新性的提出利用内积模极值法和循环相减相结合进行阻尼诊断的方法。首先,应用内积模极值法识别出信号的某一阶模态参数,从原信号中除去该阶估计信号。然后,重复这种内积运算和相减步骤,形成迭代,模态之间的相互干扰在迭代计算过程中得到消减,提高各阶阻尼的识别精度。实验采用该方法进行悬臂梁阻尼识别,并改变悬臂梁阻尼模拟裂纹出现,当粘贴一片阻尼片时,在60 Hz和200 Hz附近模态的阻尼分别产生了0.000 019和0.000 112的变化。结果表明,内积模极值法和循环相减相结合可以准确识别出阻尼的微小变化,在工程上可以让阻尼成为一个重要的参数参与悬臂梁的故障诊断。更多还原

【Abstract】 The cantilever beam structure is small damping system,modal damping is sensitive to crack fault.In order to solve the problem that traditional damping identification method has big error,the inner product modulus maximum method combined with circular subtraction is proposed to do damping identification.Firstly,the inner product modulus maximum method is applied to identify a modal parameter of signals for subtracting the estimated signal from original signals.Then,repeat these steps of this inner product operation and subtraction to become the iteration.The modal interference is decreased in the process of iteration,and the identification of each modal is more accurate.This method is applied to diagnose cantilever beam damping in the experience,and change the cantilever beam damping to simulate the crack.When one damping slice pasted on the beam,the damping produced the change of 0.000 019 and 0.000 112 in the vicinity of 60 Hz and200 Hz,respectively.Results show that the inner product modulus maximum method combined with circular subtraction can accurately identify the damping small change.The damping will be recognized as an important parameter in the fault diagnosis of beam.更多还原