Damage Location Identification For Tower Structure Based On Flexural-Torsional Information

The tower structure is a type of high-rise structure that designed for controlling the wind load, which is widely used in the radio and television, communication, transmission industry etc. Under the environmental erosion, material aging, fatigue and mutagenic effect etc, some local structural damage appear and caused by the change of structural physical parameters and dynamic characteristics. The wavelet analysis has the fine time-frequency localizing characteristics and is very sensitive to the singular points of signal, it can be used to detect abnormal signal to extract damage characteristic. Based on the study of civil and abroad scholars to structural damage identification methods in this paper, the standard deviation of displacement (angular displacement) is used as damage index, and wavelet transform is used for damage identification and localization.Based on the characteristics of wavelet basis function and the differences of analysis effects select the bior6.8 wavelet to analysis of damages in this paper. The standard deviation of angular displacement is the function about the torsional stiffness, if damages occur to the structure, the torsional stiffness will have inevitable changes, while the torsional rigidity calculation is a key of the structural dynamic response analysis under the action of tower torsional deformation.According to the lattice tower with uniform stiffness and abrupt change in stiffness under the action of tower torsional deformation, combining with the method of information expansion and information truncation, eliminate the effects of Gibbs phenomenon, mutual interference of damages and interference of abrupt change in stiffness to the nearby signals etc, accurate identify the location of single damage and multi-damage, verifies the effectiveness that damage identification for tower structure under the function of torsional deformation.According to the lattice tower under the function of horizontal loads and torsion, use the combination of flexural-torsional information for damage location identification of the single bar. Based on the impact to pick up the damage information of sensors arrangement position, propose the way of sensors arrangement in this paper, effectively distinguish the type of damage bar and narrow the judgment scope of the damage.Finally, using the obtained information of sensors omnidirectional arrangement to judge the damage position of multi-bar, not only to distinguish the type of damage bars, also discriminate the different combinations of the same type of damage bars, and show that the practical significance of multi-bar damage identification through comparison with the single bar damage.