爆炸荷载下钢管混凝土柱抗爆性能研究

发布时间：2018-04-16 08:02

本文选题：爆炸冲击波 + 钢管混凝土柱　；参考：《长安大学》2013年博士论文

【摘要】：建筑结构除了承受静动荷载以外，也可能遭受到由于爆炸恐怖袭击、偶然燃气爆炸等各种因素引发的爆炸冲击荷载。钢管混凝土结构由于其具有受力合理、承载力高、抗震性能好、施工方便、经济效益显著等优势而在土木工程中得到广泛应用。研究该结构在爆炸冲击荷载下的动态响应具有非常重要的理论意义及工程应用价值。本文采用理论分析、试验研究和数值模拟相结合的方法，对爆炸冲击波与钢管混凝土柱相互作用，爆炸荷载作用下钢管混凝土柱的动态响应、破坏模式和破坏机理等方面展开系统的研究。主要的研究工作和结论如下：（1）对钢管混凝土柱构件进行了2发3柱在不同药量、不同比例距离下的静爆试验。测得柱迎爆面和背爆面柱的柱顶、柱中、柱底的超压分布，以及振动加速度和最终位移，为准确预测作用在钢管混凝土柱上的爆炸荷载和评估钢管混凝土柱的破坏形态及破坏机理提供试验依据。试验结果表明，对于刚度较大的结构构件来说，受迎爆面负压区、背爆面的影响很小，可以忽略不计，仅考虑迎爆面的正压区作用效应；当爆炸场中的反射环境较为简单时，测量柱迎爆面反射超压时，可以通过测量自由场中的反射超压近似得到；并且得到了试验爆炸荷载作用下相应的钢管混凝土柱的破坏形态。（2）研究了爆炸冲击波与钢管混凝土柱之间的相互作用。通过试验结果中的钢管混凝土柱迎爆面的超压分布，与已有的经验超压公式进行比较，选择TM5-1300中的各爆炸特征参数，为本文爆炸荷载的预测依据，为研究爆炸荷载作用下钢管混凝土柱动态响应提供可靠的爆炸荷载预测。（3）建立爆炸冲击波及其与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，采用流固耦合法，通过选取合理的材料模型、沙漏控制方法、边界条件等因素，建立爆炸冲击波与钢管混凝土柱相互作用的数值模型。通过与试验结果的对比，，验证数值方法的正确性，并进行了参数分析。研究结果表明，含钢率对爆炸波与柱相互作用的影响并不明显，截面形状和截面尺寸对爆炸波与柱相互作用的影响较为突出，相同的爆炸环境下，圆形截面柱迎爆面的爆炸荷载强度低于方形截面柱。（4）基于等效单自由度体系对钢管混凝土柱的动态响应进行理论分析，引入圆形钢管混凝土柱等效迎爆面的概念，采用延性系数计算出了等效体系在三角形脉冲荷载下的最大动位移，并通过与试验的对比验证了理论计算的可靠性。（5）建立钢管混凝土柱在爆炸荷载作用下动态响应的数值模拟方法。并将数值模拟结果、试验结果、理论计算结果进行对比分析。并通过大量的数值模拟，进行参数分析，结果表明，随比例距离的增大，柱中点的水平最大位移和残余位移明显减小，并且衰减很快，当比例距离大于0.3m/kg1/3时，可忽略比例距离对柱中水平位移的影响；降低加载速率和减小截面尺寸，能够有效的降低钢管混凝土柱在爆炸荷载下柱中的水平位移；提高混凝土和钢材的抗压强度、增大含钢率，均能在一定程度上提高钢管混凝土柱的抗爆性能；当方形截面柱边长等于圆形柱直径时，相比圆形柱截面，尽管方形钢管混凝土柱有近似于两倍的惯性矩，但是方柱的截面不利于爆炸荷载的绕射，其迎爆面积相当于圆柱等效迎爆面的四倍，因此，圆形截面柱有较强的抵御爆炸荷载的能力。（6）钢管混凝土柱在爆炸荷载作用下的破坏模式分别为：“高峰值低持时”的冲量荷载作用下，易发生剪切破坏；“低峰值高持时”的准静态荷载作用下，易于发生弯曲变形；而在动力荷载的作用下，钢管混凝土柱倾向于发生弯剪破坏。
[Abstract]:In addition to building structures subjected to static loads, may also suffer due to the terrorist attacks of explosion, explosion shock loading caused by gas explosion and other various factors. Concrete filled steel tubular structure because of its reasonable stress, high bearing capacity, good anti-seismic performance, convenient construction, obvious economic benefit and advantages in civil engineering widely application. It has very important theoretical significance and engineering application value to research on dynamic response of the structure under blast loading. This paper uses the method of theoretical analysis, experimental research and numerical simulation on the combination of the explosion shock wave and concrete filled steel tube column interaction, the dynamic response of CFST columns under blast load, start system the study on the failure mode and failure mechanism. The main research work and conclusions are as follows:
(1) on the STCC component of 2 rounds of 3 columns in different dosage, different ratio of distance under static explosion test. The measured column blasting top surface and the back surface of the explosion, column, overpressure distribution at the bottom of the column, and the vibration acceleration and final displacement, to provide the experimental basis for accurate prediction the role in concrete filled steel tubular column on concrete filled steel tube column explosion load and evaluate the failure mode and the failure mechanism. The experimental results show that the structure stiffness of large, the face of blasting pressure area, the back blasting effect is small and can be ignored, only consider the blasting effect when the positive pressure zone; reflect the environment in the explosion field is relatively simple, measuring column face of blasting reflection overpressure, through reflection measurements in the free field pressure approximation; and the failure modes of concrete filled steel tubular columns corresponding test under explosion load.
(2) to investigate the interaction between shock wave and concrete filled steel tubular columns. Concrete filled steel tubular columns through the test results of the blast overpressure distribution of overpressure formula and the existing experience, choose the explosion characteristic parameters in TM5-1300, based on the prediction of blast loads, providing reliable explosion load the prediction for the research of response under explosion load dynamic steel pipe concrete column.
(3) establish a numerical simulation method of explosion shock wave and its interaction with the steel pipe concrete column. The explicit dynamic procedure based on ANSYS/LS-DYNA, using fluid solid coupling method, by selecting the reasonable material model, hourglass control method, boundary condition, a numerical model of explosion shock wave and concrete filled steel tube column interaction through the comparison. With the test results, verify the correctness of numerical method, and the parameters were analyzed. The results show that the influence of rate of steel of blast wave and column interaction is not obvious and the influence of section shape and section size of blast wave and column interaction is more prominent, the same explosive environment, the circular column of attack the explosion intensity of explosion load is below the square section column.
(4) the theoretical analysis of the dynamic equivalent single degree of freedom system of CFST column based on response, the equivalent of concrete filled circular steel tubular column blasting surface concept, ductility coefficient calculated by the equivalent system in the triangular pulse maximum displacement under load, and through the contrast test and verify the reliability of the theoretical calculation.
(5) the establishment of CFST columns under blast loading numerical simulation method. The dynamic response and the numerical simulation results and test results, the theoretical calculation results were compared and analyzed. Through numerical simulation, parameter analysis, results show that with increasing the ratio of the distance, the midpoint of the column level of maximum displacement and residual displacement decrease and decay quickly, when the ratio of the distance is greater than 0.3m/kg1/3, but ignoring the effect of the ratio of the distance of horizontal displacement of the column; reduce the loading rate and the size of section, can effectively reduce the horizontal displacement of CFST column under explosive load in the column; improve the compressive strength of concrete and steel, increasing with the the rate of steel, can improve the antiknock performance of concrete filled steel tubular columns in a certain extent; when the square section column is equal to the diameter of the circular column, compared with circular section column, as square steel The soil column has approximately two times of inertia moment, but the cross section of the square column is not conducive to the diffraction of the explosive load. The area of the blast hole is equivalent to four times that of the cylinder equivalent to the detonation surface. Therefore, the circular section column has a strong ability to resist explosion load.
(6) concrete filled steel tube column under explosion load failure mode are: "impulse load high peak low duration", prone to shear failure; quasi static loading is low to high peak ", prone to bending deformation; in dynamic loads, inclined concrete in place of steel pipe column bending shear failure.

【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU398.9

【引证文献】