小波包能量谱在古木框架结构的损伤预警

STRUCTURAL DAMAGE ALARMING FOR ANCIENT WOOD FRAME STRUCTURE BASED ON WAVELET PACKET ENERGY SPECTRUM

采用结构振动测试和小波包能量谱,确定结构发生的整体性能退化和局部损伤的大小及位置,应用于大型古木建筑结构的损伤预警中。通过有限元模拟得到结构的加速度响应信号,获得各阶子信号损伤前、后能量谱的变化来评价结构的损伤状态。得出结论:结构的自振频率对平面古木框架结构的损伤不敏感,很难确定损伤的位置。随着损伤程度的增大,各阶子信号能量谱的变化呈正比增大,可以定性和定量描述结构的损伤状态;小波各阶子信号能量谱的变化量与损伤所处位置有关,其中榫卯节点损伤程度最大,梁跨中损伤程度次之,柱础损伤程度最小,说明它对榫卯节点处的损伤比较敏感。

The structural performance degradation and the size and location of damage are determined by structural vibration test and wavelet packet energy spectrum,which can be used for the early damage warning of large ancient wood frame architectures.The acceleration signal of dynamic response is obtained by finite element simulation,the change of signal energy spectrum is obtained to evaluate the structural damage state.It is concluded that the structural natural frequencies are not sensitive to the plane ancient wood frame structure,it is difficult to determine the damage location.With the increase of damage degree,the change of signal energy spectrum increases,which can describe the structural damage state qualitatively and quantitatively.The variation of wavelet sub-signal energy spectrum is related to the location of damage,it is shown that the damage degree is most sensitive to the joint of mortise and tenon,secondly in the midspan of beam,finally in the bottom of column.