【摘要】 局域少数点位的变形监测往往难以反馈复杂柔性防护系统的实际工作形态，常造成预警误报，为此提出了基于多点分布式的柔性防护系统变形视觉采集分析方法。利用帧间光流算法实现了落石冲击下柔性防护网系统全场二维速度场识别，据此建立了速度幅值二维分布图，通过相邻帧图像的速度分布差值图实现了柔性防护系统全场冲击变形状态的实时追踪，进一步提出了复杂运动叠加情形下柔性防护网系统稠密测点变形高鲁棒性提取算法，并分析了其变形规律同时提取了最大变形量，实现了有限测点监测到无限分布式传感的突破。设计了三跨柔性防护系统足尺模型，开展了750 kJ落石冲击试验，通过高速相机非接触式监测了落石冲击防护系统全过程影像数据。研究表明：所提议方法实现了落石冲击下柔性防护系统全场变形状态非接触、全历程追踪，冲击过程包含落锤接触防护系统、最大冲击变形与触底反弹三个阶段；为验证所提方法的可靠性，提取了落石冲击下柔性防护系统跨中区域冲击大变形曲线，发现750 kJ能量冲击下柔性防护系统的最大变形量为-6.201 m,与数值模拟和理论计算结果的相对误差分别为6.19%和0.93%。所提方法实现了足尺冲击试验中柔性防护系统工作形态的远程监测，有潜力应用于落石灾害下柔性防护系统的形态评价。更多还原

【Abstract】 Deformation monitoring at a few local measurement points of a flexible barrier system usually makes it difficult to reflect its actual working state, which often causes false warnings. To address the above problem, a multipoint and distributed vision monitoring method for flexible barrier systems was developed. The full-field two-dimensional velocity of the flexible barrier system under rockfall impact was calculated by the optic flow algorithm. A full-field two-dimensional velocity amplitude distribution map was constructed and the velocity distribution difference map of adjacent frames was used to track the deformation state of the flexible barrier system in real-time. In addition, a highly robust dense deformation extraction algorithm for the flexible barrier system was developed in the case of captured images containing complex motions. The deformation pattern was also investigated and the maximum deformation of the flexible barrier system was extracted. The proposed method achieved a breakthrough from limited point monitoring to infinite distributed sensing. A full-scale experimental model of a three-span flexible barrier system was designed, the rockfall impact test with an energy of 750 kJ was conducted, and a high-speed camera was used to remotely capture image data of the flexible barrier under rockfall impact. The results show that the proposed method realizes the noncontact monitoring and the whole process tracking of the deformation pattern of the flexible barrier system under rockfall impact. The impact process has three stages, namely, rockfall contact, maximum impact deformation, and rebounded movement. To verify the robustness of the developed method, dynamic deformation curves at the middle span of the flexible barrier system under rockfall impact were extracted. It is found that the maximum elongation value of the flexible barrier system under the impact energy of 750 kJ is-6.201 m, and the relative errors of the maximum elongation value compared with the numerical analysis and theoretical results are 6.19 % and 0.93 % respectively. The proposed method implements the remote work condition monitoring of flexible barrier systems, which has the potential to be applied to the performance evaluation of flexible barriers under rockfall disasters.更多还原