爆炸荷载作用下钢柱局部屈曲的临界比例距离

发布时间：2018-11-02 19:37

【摘要】：钢结构建筑遭受爆炸荷载而倒塌,主要是由于钢柱等关键受力构件遭到破坏而引发的。在国际上众多钢柱或钢构件的爆炸破坏事件中均发现了局部屈曲这一破坏模式,爆炸引起的钢柱局部屈曲会影响钢柱的剩余承载力。工字形钢柱和方钢柱是工程结构中较常用的钢柱类型,研究爆炸荷载作用下钢柱的局部屈曲,并分析爆炸荷载作用下钢柱局部屈曲临界比例距离的关键影响因素,得到临界比例距离的计算式,为钢柱抗爆设计和合理防护安全距离的确定提供一定的参考,对结构安全和防护工程具有重要的实用价值和现实意义。本文的主要工作包括以下5项。(1)将B-R准则应用于爆炸荷载作用下典型钢柱的动力屈曲评价中,提出了爆炸荷载作用下钢柱局部屈曲的判别方法和其临界比例距离的确定方法。(2)研究了爆炸荷载作用下钢柱局部屈曲对钢柱竖向承载力的影响。研究表明,爆炸荷载作用下钢柱局部屈曲使钢柱基于竖向承载力的损伤指标突变,发生中度破坏。(3)以B-R准则为依据,研究了炸药量、板件宽厚比、钢柱高度和钢材屈服强度4个参数对爆炸荷载作用下方钢柱局部屈曲临界比例距离的影响。研究表明,炸药量和板件宽厚比是影响方钢柱局部屈曲临界比例距离的主要因素;与静力作用下方钢柱的局部屈曲控制相比,爆炸荷载作用下方钢柱的局部屈曲控制对板件宽厚比限值的要求更为严格。(4)以B-R准则为依据,针对爆炸荷载作用于工字形钢柱强轴方向的情况,研究了炸药量、翼缘宽厚比、腹板高厚比、钢柱高度和钢材屈服强度5个参数对爆炸荷载作用下工字形钢柱局部屈曲临界比例距离的影响。研究表明,炸药量和翼缘宽厚比是影响工字形钢柱局部屈曲临界比例距离的主要因素;与静力作用下工字形钢柱的局部屈曲相比,爆炸荷载作用于工字形钢柱强轴方向时,由于工字形钢柱的局部屈曲仅出现在翼缘上,钢柱腹板高厚比对其局部屈曲的影响不明显。(5)基于有限元模拟结果,考虑爆炸荷载作用下影响钢柱局部屈曲临界比例距离的关键因素,拟合出了任意炸药量引起的爆炸荷载作用下方钢柱与工字形钢柱局部屈曲的临界比例距离计算式。
[Abstract]:The collapse of steel structure subjected to explosive load is mainly caused by the destruction of key members such as steel columns. The failure mode of local buckling has been found in many explosion failure events of steel columns or steel members in the world. The local buckling of steel columns caused by explosion will affect the residual bearing capacity of steel columns. I-shaped steel columns and square steel columns are common types of steel columns in engineering structures. The local buckling of steel columns under explosive loading is studied, and the key factors affecting the critical proportional distance of local buckling of steel columns under explosive load are analyzed. The formula of critical proportional distance is obtained, which provides a certain reference for the design of steel column anti-explosion and the determination of reasonable safety distance of protection. It has important practical value and practical significance for structural safety and protection engineering. The main work of this paper includes the following five items. (1) the B-R criterion is applied to the dynamic buckling evaluation of typical steel columns under explosive loading. A method for determining the local buckling of steel columns under explosive loading and the determination of their critical proportional distance are proposed. (2) the effect of local buckling of steel columns on the vertical bearing capacity of steel columns under explosive loading is studied. The results show that local buckling of steel columns under explosive load causes sudden change of damage index of steel columns based on vertical bearing capacity and moderate failure. (3) based on B-R criterion, the quantity of explosive and the ratio of width to thickness of plates are studied. The influence of four parameters of steel column height and steel yield strength on the critical proportional distance of local buckling of steel column under explosive load. The results show that the amount of explosive and the ratio of plate width to thickness are the main factors affecting the critical ratio distance of local buckling of square steel columns. Compared with the local buckling control of steel columns under static load, the local buckling control of steel columns under explosive load is more strict to the limit value of the width to thickness ratio of plates. (4) based on B-R criterion, the local buckling control of steel columns under explosive load is more strict than the local buckling control of steel columns under static load. In view of the effect of explosive load on the direction of strong axis of I-shaped steel column, the quantity of explosive, the ratio of flange width to thickness and the ratio of web height to thickness are studied. The influence of five parameters of steel column height and steel yield strength on the critical proportional distance of local buckling of I-shaped steel column under explosive loading. The results show that the amount of explosive and the ratio of flange width to thickness are the main factors affecting the critical ratio distance of local buckling of I-shaped steel column. Compared with the local buckling of I-shaped steel column under static force, the local buckling of I-shaped steel column appears only on the flange when the explosive load acts on the strong axial direction of I-shaped steel column. The effect of the ratio of height to thickness on the local buckling of steel columns is not obvious. (5) based on the results of finite element simulation, the key factors affecting the critical proportional distance of local buckling of steel columns under explosive loads are considered. The critical proportional distance formula for local buckling of steel column and I-shaped steel column under explosive load caused by arbitrary explosive is fitted.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU391;TU352.13

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