Damage Identification in a Composite Plate using Prestack Reverse-time Migration Technique
Damage Identification in a Composite Plate using Prestack Reverse-time Migration Technique
复制标题
DOI：
10.1177/1475921705055233
复制
发表时间：
2005-09
期刊：
影响因子：
--
通讯作者：
Lei Wang;F. Yuan
中科院分区：
文献类型：
--
作者：
Lei Wang;F. Yuan
提出了物探中常用的偏移技术，对复合材料层合板中多个分层损伤进行定位和成像。在这个仿真研究中，一个带有线性阵列执行器/传感器的主动诊断系统被用来激发/接收层压板中最低模式的弯曲波。基于Mindlin板理论，采用二维显式有限差分格式综合损伤数据和传感器阵列数据散射的波场，模拟了层合材料中的波传播。然后采用叠前逆时偏移技术来解释合成传感器阵列数据并可视化损伤。根据色散关系推导出复合材料板中弯曲波的相速度和群速度，并基于射线追迹和群速度引入了波在复合材料板中偏移的激励时成像条件。然后采用相同的有限差分格式进行叠前逆时偏移，将散射能量反向传播到损伤处。在迁移过程中，层压板以横向变形速度成像。损坏的位置和尺寸可以直观地显示出来。仿真结果表明，该方法能较好地识别多层损伤，得到的图像与目标损伤具有较好的相关性。
Migration technique, which is normally used in geophysical prospecting, is proposed to locate and image multiple delamination damages in a laminated composite plate. In this simulation study, an active diagnostic system with a linear array of actuators/sensors is used to excite/receive the lowest mode of flexural waves in the laminate. The wavefield scattered from the damages and sensor array data are synthesized using a two-dimensional explicit finite difference scheme to model wave propagation in the laminate based on the Mindlin plate theory. A prestack reverse-time migration technique is then adopted to interpret the synthetic sensor array data and to visualize the damages. The phase and group velocities of flexural waves in the composite plate are derived from the dispersion relations, and subsequently an excitation-time imaging condition specifically for migration of waves in the plate is introduced based on ray tracing and group velocity. Then the prestack reverse-time migration is performed using the same finite difference scheme to back-propagate the scattered energy to the damages. During the migration process, the laminate is imaged in terms of velocity of the transverse deformation. The locations and dimensions of the damages can be visually displayed. Simulated results demonstrate that multiple delamination damages can be successfully identified and the resulting image correlates well with the target damages.