【作者】 崔莹；

【导师】 赵均海；

【作者基本信息】 长安大学 ， 结构工程， 2013， 博士

【摘要】 随着国民经济的不断发展，由于燃气泄漏、易燃易爆品堆置不当、电器老化而引发的爆炸发生几率逐渐增大，致使建筑结构受到爆炸冲击作用的可能性随之增大。同时，由于全世界范围内恐怖袭击时有发生，爆炸对于建筑结构的威胁正与日俱增。要使结构在爆炸冲击荷载作用下有着较好的抗爆性能，避免结构破坏，柱本身的抗爆性能起着非常重要的作用。复式空心钢管混凝土柱具有承载力高、塑性好、抗弯刚度大的特点，被广泛用做工程结构中的重要受力构件。因此研究复式空心钢管混凝土柱的爆炸冲击破坏效应，进而建立其损伤评估方法具有重要的理论意义和工程应用价值。本文采用试验研究和数值模拟方法对爆炸荷载下复式空心钢管混凝土柱的动态响应和损伤评估进行系统研究，具有重要的理论意义和工程应用价值。主要的研究工作和创新成果包括以下几个方面：（1）研究了爆炸冲击波与复式空心钢管混凝土柱相互作用的数值模拟方法。基于显式动力学程序ANSYS/LS-DYNA，采用ALE流固耦合的加载方式建立了考虑地面反射的爆炸荷载下钢管混凝土柱、空气及炸药的有限元数值模型；进一步研究讨论了空气有限元网格划分对数值模拟结果的影响。结果表明网格尺寸大小对冲击波传播的波形和传播时间均有较大影响。冲击波压力峰值随着网格尺寸的增加呈下降趋势，网格密度越大，冲击波压力峰值与试验采集压力峰值越接近；（2）设计完成了两发钢管混凝土柱爆炸试验。通过对测点压力及柱宏观变形的分析，结果表明在折合距离为1.1m/kg1/3的第一发试验条件的爆炸荷载作用下，柱产生的变形属于弹性变形，没有塑性变形产生，柱仍有着良好的承载能力；在折合距离为0.14m/kg1/3第二发试验条件的爆炸荷载作用下，复式空心钢管混凝土柱迎爆面柱中发生了明显的塑性弯曲变形。柱迎爆面柱底肋板上缘柱表面有一条细微未贯通裂缝存在。结果表明柱端部节点强度与构件整体强度协调对提升复式空心混凝土柱的抗爆性能尤为重要；（3）研究了复式空心钢管混凝土柱各参数对爆炸冲击波与结构柱的相互作用以及作用于柱上爆炸荷载规律的影响。通过参数分析，结果表明增大空心率可以使柱核心区混凝土承受的压力减小，从而在一定程度上改善复式空心钢管混凝土柱的抗爆性能；即使正压的作用时间一致，圆截面产生的压力值也要低于方截面，因此圆截面抗爆性能要优于方截面；提高混凝土强度等级对改善复式空心钢管混凝土柱的抗爆性能影响不大；折合距离变化对复式空心钢管混凝土柱的动态响应和抗爆性能有较大影响。柱迎爆面位移峰值的增加率随着折合距离的减小而迅速增加，压力峰值的增加率远大于折合距离的降低率，折合距离越小时，柱迎爆面压强变化也相应越敏感；（4）建立了基于复式空心钢管混凝土柱中弯曲挠度变形量的超压—冲量损伤准则。在进行大量数值模拟试算的基础上，建立了基于本文的复式空心钢管混凝土柱损伤等级分界线，即P-I曲线。并拟合建立了P-I曲线数学表达式。同时将所得公式推广到一般情况，建立了以迎爆面柱中挠度为指标的复式空心钢管混凝土柱弯曲变形损伤评估准则。更多还原

【Abstract】 With the continuous development of the national economy, accidental explosions mightalso occur because of the aging of the gas container or the electric machine and improperstorage of tinder and explosive in chemical plants. At the same time, explosion is a growingthreat to the building structure because more and more explosive terror attacks and explosiveaccidents have happened around the world. In order to keep structure having excellentexplosion resisting performance, the explosion resisting performance of column itself plays avery important role. Duplex hollow CFST (Concrete Filled Steel Tube) column has manymerits such as higher bearing capacity, better plasticity, and higher bending stiffness. Theevaluation for the explosion resisting performance of duplex hollow CFST column hasimportant theoretical significance and practical value. Experiment analysis and numericalsimulation method are integrated to study dynamic response and damage assessment ofduplex hollow CFST column subjected to blast loading in this dissertation, and the primarywork and achievements are as follows:(1) Simulation of blast wave prorogation and its interaction with duplex hollow CFSTcolumn are studied. Using a explicit dynamic finite element analysis program,ANSYS/LS-DYNA, and with ALE fluid-solid coupling method, a finite element model ofCFST column is developed for simulating dynamic response and damage assessment.Furthermore, the influence of the mesh size effect on the numerical results is also analyzed.The results show that the mesh size has greater impact on the waveform and the propagationtime. The peak pressure decreases according to the mesh size increases. The simulating resultscorrespond with the experiment results well when the mesh density increases.(2) The explosion experiments in connection with CFST columns have performed. Theexplosion experiments have been executed for the popular CFST column and the duplexhollow CFST column respectively. By analysis about column macroscopic deformation andthe pressure values of measurement points at the scale distance of1.1m/kg1/3, the results showthat the popular CFST column still has a good carrying capacity and its deformation belongsto elastic stage. And by analysis about column deformation at the scale distance of 0.14m/kg1/3, the results show that the plastic bending deformation occurs on the surface facingthe explosive of the duplex hollow CFST column and there is a minor crack on the upside ofrib plate. So, it is important to strengthen the joint of column in order to keep the explosionresisting performance of duplex hollow CFST column.(3) Parametric studies are adopted to investigate the effects of column parameters ondynamic response and damage of duplex hollow CFST column. The results show that thehollow rate increases according to the decrease of pressure in the inner concrete. The resultsalso show that explosion resisting performance of the circular section is superior to the squaresection for the former has lower pressure value under the same explosive shock wave. And,the adjustment to the concrete strength grade has little effect on explosion resistingperformance. However, the adjustment to the scale distance has great effect on explosionresisting performance of duplex hollow CFST column. The peak displacement increasesquickly according to the decrease of the scale distance. The pressure on the surface facing theexplosive changes more sensitively according to the lower value of the scale distance.(4) Damage assessment criterion for duplex hollow CFST column are discussed andestablished. A pressure-impulse damage criterion for duplex hollow CFST column is definedbased on the deflection of the surface facing the explosive of the duplex hollow CFST column,and a numerical method to generate pressure-impulse diagram (P-I curve) is established. Andfinally, Damage assessment criterion is established to evaluate the damage situation for theduplex hollow CFST column under the condition of bending deformation.更多还原