冲击荷载作用下管桁架失效机理及损伤评估方法研究

As the unexpected collision and impact incident may cause significant local damage, even progressive collapse on tubular truss, it attracts more attention to study the anti-collision design method, the evaluation after damage, strengthening and repairing of tubular truss. The project is designed to investigate the response and failure mechanisms of tubular truss subjected to impact loading, and to develop measures to evaluate the damage to structure based on experimental studies and nonlinear finite analysis. Firstly, the critical dynamic characteristic parameters of steel and weld will be calibrated based on steel coupon and welded joints tests under dynamic tensile loading. Secondly, experimental and numerical studies on the steel tube and tubular joints under impact loading will be conducted to discover the local failure mechanisms of tubular truss. Thirdly, the failure mechanisms of tubular truss subjected to impact loading and the critical factors will be studied. General models at the component level based on force and deformation relationships along with damage index will be proposed. The index and parameters for evaluating the failure mechanisms of tubular truss will be developed. Based on different damage degree of tubular truss, the method for evaluation will be developed. The simplified calculation method of ultimate bearing capacity and deformation for steel tube, tubular joint and tubular truss will be obtained, and the design method for anti-collision, strengthening and repairing will be suggested. The research achievement of the project will play an important role in evaluating the anti-collision design and overall failure of existing tubular truss, and can apply the scientific basis for engineering practice.

突发的撞击事件是引发管桁架结构局部严重损伤，发生连续倒塌的重要原因，这使管桁架结构的防撞研究引起工程实践的广泛关注，并使结构受撞后的损伤评估、防撞设计对策、及加固修复显得尤为紧要。本项目拟采用试验和有限元研究相结合的方法，开展冲击荷载作用下管桁架失效机理和损伤评估方法研究。本项目首先通过钢材和焊缝的动态材性试验标定其动力特性的关键参数，然后从构件、节点层面研究管桁架局部冲击破坏机理，进而研究冲击荷载作用下管桁架结构破坏机理与主要影响因素。从工程应用的角度出发，建立构件断面层面上的冲击力-变形关系模型，确定管桁架冲击破坏机理的指标与参数；提出针对不同损伤级别的损伤评价方法，得到钢管、管节点及管桁架的极限承载力和变形的简化计算方法，提出加固修复和防撞设计建议。项目的研究成果对于现有管桁架结构工程的防撞评估和整体失效研究具有重要意义，并可为工程设计中管桁架损伤加固和防撞设计提供科学依据。

突发的撞击事件是引发管桁架结构局部严重损伤，发生连续倒塌的重要原因，这使管桁架结构的防撞研究引起工程实践的广泛关注，并使结构受撞后的损伤评估、防撞设计对策、及加固修复显得尤为紧要。本项目拟采用试验和有限元研究相结合的方法，开展冲击荷载作用下管桁架失效机理和损伤评估方法研究。本项目首先通过钢材和焊缝的动态材性试验标定其动力特性的关键参数，然后从构件、节点层面，考虑了轴压比和腐蚀缺陷的影响，研究了未加强和加强管节点、管桁架局部冲击破坏机理，进而研究冲击荷载作用下管桁架结构破坏机理与主要影响因素。从工程应用的角度出发，建立构件断面层面上的冲击力-变形关系模型，确定管桁架冲击破坏机理的指标与参数；提出针对不同损伤级别的损伤评价方法，得到钢管、管节点及管桁架的极限承载力和变形的简化计算方法，提出加固修复和防撞设计建议。项目的研究成果对于现有管桁架结构工程的防撞评估和整体失效研究具有重要意义，并可为工程设计中管桁架损伤加固和防撞设计提供科学依据。