摘要
为了揭示桥梁防撞装置工作机理,设计了防护装置性能评估冲击实验系统,用于评估防撞装置的冲击动力特性。以钢-聚氨酯复合防撞装置为例,研究了聚氨酯对防撞装置性能的影响。实验结果表明:聚氨酯显著影响冲击力的峰值和时间历程;防撞装置的变形能力随着填充率的不同而变化;较低的填充率在反复冲击下表现出更强的非线性变形。聚氨酯填充率对装置的失效模式产生了显著影响:在未填充聚氨酯的情况下,钢板在第二次撞击后即发生屈曲失效;填充聚氨酯有效抑制了钢板顶部的局部屈曲,减轻了结构的损坏。该实验教学有助于提高学生优化设计桥梁防撞装置的能力。
[Objective]Ship collisions are among the leading causes of damage to river and estuary bridges,where protective devices play a critical role in mitigating impact damage.To deepen the understanding of bridge protective device mechanisms,this study introduces an experimental system designed specifically to evaluate impact dynamics.The impact testing device used to assess protective device performance consists of three main components,namely,a traction drive system,a horizontal impact system,and a testing system.This setup enables the precise measurement and analysis of various protective devices under repeated impact tests,focusing particularly on the effect of polyurethane filling rates on impact resistance.[Methods]In this study,steel–polyurethane composite protective devices were designed,fabricated,and subjected to systematic impact tests.During these tests,data were collected on the time history of impact force,peak impact force,and deformation of the protective devices,providing a detailed assessment of their performance.The experimental data were also incorporated into teaching practices,helping students understand the dynamic behavior and operational principles of composite protective structures.[Results]The results indicated that the polyurethane filling rate significantly affects both the peak impact force and impact duration.During the first impact,filled polyurethane devices exhibited a peak impact force 1.49 times greater than that of unfilled devices.Additional impact cycles further increased the peak impact force but progressively decreased the impact duration.This trend indicates that,with cumulative impacts,the compressed polyurethane stiffens the structure,gradually reducing the energy absorption capacity of the protective device.Variations in the polyurethane filling rates also impact the overall deformation capacity,i.e.,under identical impact energy,a higher polyurethane filling rate resulted in reduced cumulative deformation.For example,without polyurethane filling,the cumulative deformation after two impacts reached 46.5 cm,whereas with polyurethane filling,the cumulative deformation after four impacts was limited to only 13.3 cm.At lower polyurethane filling rates,the device exhibited enhanced nonlinear deformation characteristics under repeated impacts,which improved energy absorption but led to more significant damage to the protective structure.The polyurethane filling rate also significantly influenced the failure mode of the device.Without polyurethane filling,the steel plate experienced buckling failure after the second impact,resulting in a marked reduction in energy absorption capacity.By contrast,with the appropriate polyurethane filling,local buckling at the top of the steel plate was effectively suppressed,reducing structural damage significantly.However,at high-impact energy levels,buckling may still occur at the bottom of the steel plate,ultimately leading to overall failure,which indicates that the polyurethane filling rates should be optimized for specific impact scenarios.[Conclusions]In experimental teaching,the application of these findings through a blend of theoretical and practical approaches not only enhances students’understanding of impact resistance mechanisms in bridge protective devices but also improves their experimental skills and fosters innovative thinking.Through exploration of material properties,mechanical behavior,and design optimization,students gain practical insights into bridge protection technology.This study provides valuable guidance for optimizing bridge protective device designs,especially in scenarios where bridge structures face potential ship collisions.Properly designed polyurethane filling can significantly enhance the impact resistance of protective devices,contributing to the long-term stability and durability of bridge structures.
作者
郭悬
刘畅
康爱红
李波
GUO Xuan;LIU Chang;KANG Aihong;LI Bo(College of Architectural Science and Engineering,YangZhou University,Yangzhou 225127,China)
出处
《实验技术与管理》
北大核心
2025年第5期82-89,共8页
Experimental Technology and Management
基金
江苏省自然科学基金面上项目(BK20231334)
中国建设教育协会教育教学科研课题(2023028,2023244)。
关键词
冲击实验系统
桥梁防撞装置
聚氨酯填充率
撞击力
失效模式
impact testing system
bridge anti-collision device
polyurethane filling rate
impact force
failure modes
