【摘要】 将数字散斑相关法应用于测量结构振动的位移和频率,对振动结构标记人为散斑或者利用结构本身较明显的天然散斑作为目标点,利用摄像机连续采集一系列数字图像,结合数字散斑相关法,对目标点散斑进行识别,计算其在图像中位置的变化以获得目标点位移,进而通过FFT变化得到频率。在振动台水平正弦激励某模型结构的实验中,通过与位移计测量结果的比较证明,所提出的方法是可行的,并且具有工程可接受的精度。通过试验详细探讨了散斑的选取对测量结果的影响。本文方法可方便的应用于桥梁、建筑、空间结构等土木工程结构的振动位移与频率的非接触、全景式多点同时监测。更多还原

【Abstract】 The Digital Speckle Correlation Method(DSCM) was applied to the measurement of structural vibration displacement and frequency.The procedures for this measurement technique include:(1) to mark one or more artificial speckles or to select some existing obvious natural speckles on the vibrating structure as the movement target;(2) to get a series of continuous digital images from the video for capturing the structural vibration;(3) to obtain the displacement of movement target by locating the selected speckle in each image using DSCM;(4) to obtain the vibration frequency using Fast Fourier Transformation(FFT) from the displacement time-history.This method is proved to be feasible by comparing the results with those obtained by a displacement meter for sinusoidal horizontal vibrations of scaled structures excited by a vibration platform.The measurement accuracy is acceptable for engineering applications.The influence of speckle selection on the measurement accuracy was experimentally investigated in detail.The presented technique can be conveniently applied to the non-contact and panoramically simultaneous multi-target measurement of vibration displacement and frequency of civil engineering structures such as bridges,buildings and space structures.更多还原