旋转部件在交通运输、风能发电等诸多领域具有重要作用。三维数字图像相关方法(Three-Dimensional Digital Image Correlation,3D–DIC)作为一种非接触光学测量手段,能够获取旋转部件在运转过程中的全场位移、变形及振动信息,从而为故...旋转部件在交通运输、风能发电等诸多领域具有重要作用。三维数字图像相关方法(Three-Dimensional Digital Image Correlation,3D–DIC)作为一种非接触光学测量手段,能够获取旋转部件在运转过程中的全场位移、变形及振动信息,从而为故障诊断、健康监测以及气动结构优化设计提供重要数据支撑。本文对近年来3D–DIC技术的发展与应用进行了全面综述。首先介绍了3D–DIC技术的基本原理及其针对旋转物体的变形测量系统;针对大角度旋转测量中出现的退相关问题,详细阐述了国内外学者在初值估计和形函数设计等方面所提出的改进。随后,通过若干典型应用案例,展示了该技术相较于传统变形测量手段的优势。最后,对该技术的应用前景和发展趋势进行了展望。展开更多
Results of in-situ vibration measurement carried out at Tianjin West Elevated Railway Station which has the trains running on the station structure were reported. The main excitation source is the train passing throug...Results of in-situ vibration measurement carried out at Tianjin West Elevated Railway Station which has the trains running on the station structure were reported. The main excitation source is the train passing through the station. Vibration measurements were recorded in the vertical direction of the supporting track beam, the platform and the steel truss beam of the waiting hall, as well as in the vertical, longitudinal and transverse directions of the roof arch base of the station. Acceleration time responses were obtained. The maximum value, vibration level and one-third octave band RMS spectra of the measured accelerations were studied. The propagation of vibration in different structural floors was discussed. The influence of train speed, distance to the vibration source and the type of train on the structural vibration were analyzed. Results show that the vibration level increases with the train speed, while it attenuates with the distance to the track. Furthermore, the vibration responses of different structural floors were compared, and it is noted that the vertical vibration of the bottom slab of the platform is most severe and the transverse vibration of the roof arch base is the smallest. The results provide reference on the vibration characteristics and vibration energy distribution of this type of "Train on building frame" system used as an elevated railway station.展开更多
The measured data of vibrations induced by excavation of deep-buried cavern and open pit with method of bench blasting were analyzed by Fourier Transform and Wavelet Transform,and the characteristics of vibrations ind...The measured data of vibrations induced by excavation of deep-buried cavern and open pit with method of bench blasting were analyzed by Fourier Transform and Wavelet Transform,and the characteristics of vibrations induced under these two circumstances were studied.It is concluded that with the similar rock condition and drilling-blasting parameters,vibration induced by bench blasting in deep-buried cavern has a higher main frequency and more scattered energy distribution than that in open pit.The vibration induced by bench blasting in open pit is mainly originated from the blast load,while the vibration induced by bench blasting in deep-buried cavern is the superposition of vibrations induced by blast load and transient release of in-situ stress.The vibration induced by transient release of in-situ stress increases with the stress level.展开更多
文摘旋转部件在交通运输、风能发电等诸多领域具有重要作用。三维数字图像相关方法(Three-Dimensional Digital Image Correlation,3D–DIC)作为一种非接触光学测量手段,能够获取旋转部件在运转过程中的全场位移、变形及振动信息,从而为故障诊断、健康监测以及气动结构优化设计提供重要数据支撑。本文对近年来3D–DIC技术的发展与应用进行了全面综述。首先介绍了3D–DIC技术的基本原理及其针对旋转物体的变形测量系统;针对大角度旋转测量中出现的退相关问题,详细阐述了国内外学者在初值估计和形函数设计等方面所提出的改进。随后,通过若干典型应用案例,展示了该技术相较于传统变形测量手段的优势。最后,对该技术的应用前景和发展趋势进行了展望。
基金Project(50938008)supported by the Natural Science Foundation of Beijing,ChinaProject(2012JBM007)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(NCET-11-0571)supported by the Program for New Century Excellent Talents in University,China
文摘Results of in-situ vibration measurement carried out at Tianjin West Elevated Railway Station which has the trains running on the station structure were reported. The main excitation source is the train passing through the station. Vibration measurements were recorded in the vertical direction of the supporting track beam, the platform and the steel truss beam of the waiting hall, as well as in the vertical, longitudinal and transverse directions of the roof arch base of the station. Acceleration time responses were obtained. The maximum value, vibration level and one-third octave band RMS spectra of the measured accelerations were studied. The propagation of vibration in different structural floors was discussed. The influence of train speed, distance to the vibration source and the type of train on the structural vibration were analyzed. Results show that the vibration level increases with the train speed, while it attenuates with the distance to the track. Furthermore, the vibration responses of different structural floors were compared, and it is noted that the vertical vibration of the bottom slab of the platform is most severe and the transverse vibration of the roof arch base is the smallest. The results provide reference on the vibration characteristics and vibration energy distribution of this type of "Train on building frame" system used as an elevated railway station.
基金Project(2010CB732003) supported by the National Basic Research Program of ChinaProjects(50725931,50779050 and 50909077) supported by the National Natural Science Foundation of China
文摘The measured data of vibrations induced by excavation of deep-buried cavern and open pit with method of bench blasting were analyzed by Fourier Transform and Wavelet Transform,and the characteristics of vibrations induced under these two circumstances were studied.It is concluded that with the similar rock condition and drilling-blasting parameters,vibration induced by bench blasting in deep-buried cavern has a higher main frequency and more scattered energy distribution than that in open pit.The vibration induced by bench blasting in open pit is mainly originated from the blast load,while the vibration induced by bench blasting in deep-buried cavern is the superposition of vibrations induced by blast load and transient release of in-situ stress.The vibration induced by transient release of in-situ stress increases with the stress level.
