Lamb Wave(LW) simulation under time-varying conditions is an effective and low cost way to study the problem of the low reliability of the structural health monitoring methods based on the LW and Piezoelectric Transdu...Lamb Wave(LW) simulation under time-varying conditions is an effective and low cost way to study the problem of the low reliability of the structural health monitoring methods based on the LW and Piezoelectric Transducer(PT). In this paper, a multiphysics simulation method of the LW propagation with the PTs under load condition is proposed. With this method, two key mechanisms of the load influence on the LW propagation are considered and coupled with each other. The first mechanism is the acoustoelastic effect which is the main reason of the LW velocity change. The second key mechanism is the load influence on piezoelectric materials, which results in a change of the amplitude. Based on the computational platform of the COMSOL Multiphysics, a multiphysics simulation model of the LW propagation with the PTs under load condition is established. The simulation model includes two physical phenomena. The first one is called solid mechanics, which is used to simulate the acoustoelastic effect being combined with the hyperelastic material properties of the structure in which the LW propagates. The second one is called electromechanical coupling, which considers the simulation of the piezoelectric effect of the PTs for the LW excitation and sensing. To simulate the load influence on piezoelectric materials, a non-linear numerical model of the relationship between the load and the piezoelectric coefficient d31 is established based on an experiment of the load influence on the LW. The simulation results under uniaxial tensile load condition are obtained and are compared with the data obtained from the experiment. It shows that the variations of the phase velocity and amplitude of the LW obtained from the simulation model match the experimental results well.展开更多
针对风电机组齿轮箱在时变工况下的振动信号具有非平稳特性,提出一种谱峭度和Vold-kalman阶比跟踪(Vold-Kalman Filter Based Order Tracking,VKF-OT)相结合的故障特征提取方法。以转频和啮合频率作为VKF-OT的提取频率,获得随转速变化...针对风电机组齿轮箱在时变工况下的振动信号具有非平稳特性,提出一种谱峭度和Vold-kalman阶比跟踪(Vold-Kalman Filter Based Order Tracking,VKF-OT)相结合的故障特征提取方法。以转频和啮合频率作为VKF-OT的提取频率,获得随转速变化的阶比信号,通过阶比信号复包络直接求两种频率分量的幅值、相位,经实验分析这种方法能保留齿轮箱的瞬变信息。而后计算两种频率分量的谱峭度,以最大谱峭度对应的频率带能量与原阶比信号总能量之比作为故障特征,最后采用高斯混合模型对风电机组齿轮箱在不同工况下的150组振动信号进行特征描述,运用最大贝叶斯分类器实现故障识别。故障识别率表明该方法可有效地识别任意时变工况下的齿轮早期局部微弱故障。展开更多
针对齿轮在时变工况下的振动具有非线性、非平稳的特性,提出Vold-Kalman阶比跟踪(Vold-Kalman filter based order tracking,简称VKF-OT)和去趋势波动分析(detrended fluctuation analysis,简称DFA)相结合的一种特征提取方法。该方法以...针对齿轮在时变工况下的振动具有非线性、非平稳的特性,提出Vold-Kalman阶比跟踪(Vold-Kalman filter based order tracking,简称VKF-OT)和去趋势波动分析(detrended fluctuation analysis,简称DFA)相结合的一种特征提取方法。该方法以齿轮转频和啮频作为VKF-OT的提取频率,获取任意时变工况下的两类阶比信号,减弱或消除转速变化所引起的频率调制干扰,通过求解复包络得到两种频率分量的精确幅值和相位以保留齿轮状态的瞬变信息。在此基础上,引入去趋势波动法分别处理原信号、转频和啮频阶比信号,消除负载变化所产生的幅值调制干扰,对比3种信号的双对数波动函数图,选定齿轮振动信号的特征向量。通过对齿轮不同工作状态下的150组振动信号进行实验,结果表明该方法所提取的故障特征可有效地区分任意时变工况下的齿轮早期局部微弱故障。展开更多
基金supported by the National Natural Science Foundation of China(Nos.51635008 and 51575263)the Fok Ying Tung Education Foundation of China(No.161048)+1 种基金the Program for Distinguished Talents of Six Domains in Jiangsu Province of China(No.GDZB-035)the Priority Academic Program Development of Jiangsu Higher Education Institutions of China
文摘Lamb Wave(LW) simulation under time-varying conditions is an effective and low cost way to study the problem of the low reliability of the structural health monitoring methods based on the LW and Piezoelectric Transducer(PT). In this paper, a multiphysics simulation method of the LW propagation with the PTs under load condition is proposed. With this method, two key mechanisms of the load influence on the LW propagation are considered and coupled with each other. The first mechanism is the acoustoelastic effect which is the main reason of the LW velocity change. The second key mechanism is the load influence on piezoelectric materials, which results in a change of the amplitude. Based on the computational platform of the COMSOL Multiphysics, a multiphysics simulation model of the LW propagation with the PTs under load condition is established. The simulation model includes two physical phenomena. The first one is called solid mechanics, which is used to simulate the acoustoelastic effect being combined with the hyperelastic material properties of the structure in which the LW propagates. The second one is called electromechanical coupling, which considers the simulation of the piezoelectric effect of the PTs for the LW excitation and sensing. To simulate the load influence on piezoelectric materials, a non-linear numerical model of the relationship between the load and the piezoelectric coefficient d31 is established based on an experiment of the load influence on the LW. The simulation results under uniaxial tensile load condition are obtained and are compared with the data obtained from the experiment. It shows that the variations of the phase velocity and amplitude of the LW obtained from the simulation model match the experimental results well.
文摘针对风电机组齿轮箱在时变工况下的振动信号具有非平稳特性,提出一种谱峭度和Vold-kalman阶比跟踪(Vold-Kalman Filter Based Order Tracking,VKF-OT)相结合的故障特征提取方法。以转频和啮合频率作为VKF-OT的提取频率,获得随转速变化的阶比信号,通过阶比信号复包络直接求两种频率分量的幅值、相位,经实验分析这种方法能保留齿轮箱的瞬变信息。而后计算两种频率分量的谱峭度,以最大谱峭度对应的频率带能量与原阶比信号总能量之比作为故障特征,最后采用高斯混合模型对风电机组齿轮箱在不同工况下的150组振动信号进行特征描述,运用最大贝叶斯分类器实现故障识别。故障识别率表明该方法可有效地识别任意时变工况下的齿轮早期局部微弱故障。
文摘针对齿轮在时变工况下的振动具有非线性、非平稳的特性,提出Vold-Kalman阶比跟踪(Vold-Kalman filter based order tracking,简称VKF-OT)和去趋势波动分析(detrended fluctuation analysis,简称DFA)相结合的一种特征提取方法。该方法以齿轮转频和啮频作为VKF-OT的提取频率,获取任意时变工况下的两类阶比信号,减弱或消除转速变化所引起的频率调制干扰,通过求解复包络得到两种频率分量的精确幅值和相位以保留齿轮状态的瞬变信息。在此基础上,引入去趋势波动法分别处理原信号、转频和啮频阶比信号,消除负载变化所产生的幅值调制干扰,对比3种信号的双对数波动函数图,选定齿轮振动信号的特征向量。通过对齿轮不同工作状态下的150组振动信号进行实验,结果表明该方法所提取的故障特征可有效地区分任意时变工况下的齿轮早期局部微弱故障。
