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1.
Fook Choon Choi Jianchun Li Bijan Samali Keith Crews 《Journal of Mechanical Science and Technology》2007,21(6):903-907
Using vibration methods for the damage detection and structural health monitoring in bridge structures is rapidly developing.
However, very little work has so far been reported on timber bridges. This paper intends to address such shortcomings by experimental
investigation on a timber beam using a vibration based method to detect damage. A promising damage detection algorithm based
on modal strain energy was adopted and modified to locate/evaluate damage. A laboratory investigation was conducted on a timber
beam inflicted with various damage scenarios using modal tests. The modal parameters obtained from the undamaged and damaged
state of the test beam were used in the computation of damage index, were then applied using a damage detection algorithm
utilising modal strain energy and a statistical approach to detect location of damage. A mode shape reconstruction technique
was used to enhance the capability of the damage detection algorithm with limited number of sensors. The test results and
analysis show that location of damage can be accurately identified with limited sensors. The modified method is less dependent
on the number of modes selected and can detect damage with a higher degree of confidence. 相似文献
2.
Jyrki Kullaa 《Mechanical Systems and Signal Processing》2011,25(8):2976-2989
Discrimination between three different sources of variability in a vibration-based structural health monitoring system is investigated: environmental or operational effects, sensor faults, and structural damage. Separating the environmental or operational effects from the other two is based on the assumption that measurements under different environmental or operational conditions are included in the training data. Distinguishing between sensor fault and structural damage utilizes the fact that the sensor faults are local, while structural damage is global. By localizing the change to a sensor which is then removed from the network, the two different influences can be separated. The sensor network is modelled as a Gaussian process and the generalized likelihood ratio test (GLRT) is then used to detect and localize a change in the system. A numerical and an experimental study are performed to validate the proposed method. 相似文献
3.
提出了一种对重载的Stewart六自由度运动平台动力学模型局部线性化的新方法,将其六个作动杆简化成质量-弹簧系统.然后采用转移矩阵法将各局部坐标系中建立的质量矩阵、刚度矩阵、阻尼矩阵以及系统的位移和所受外力均转移到总的固定坐标系,运用D'Alembert原理建立其振动的线性运动微分方程.最后通过结合Stewart平台的运动学反解计算方法,对该平台在运动过程中的自振频率进行了分析和计算,计算结果表明对于这种重载的Stewart运动平台,其各个自振频率在整个工作空间内的变化幅度不大,该结果为重载Stewart平台的设计和控制提供了理论依据,已被成功应用于
Study on the analysis and caculation of the natural frequencies of the stewart motion platform with six degree of freedom
DAI Yu-liang ZHU Ying YU Ke-yun LIU Zu-yuan
作者单位:戴余良(武汉理工大学,交通学院,湖北,武汉,430063;海军工程大学,船舶与动力学院,湖北,武汉,430033) 相似文献