爆炸荷载作用下钢管混凝土柱的动力响应及损伤评估
发布时间：2018-12-14 07:31
【摘要】：随着恐怖袭击目标的转变和天然气爆炸事故的增多,在进行民用建筑设计时,适当考虑爆炸荷载非常必要。采用抗爆性能优越的材料和结构体系是最有效、最经济的抗爆设计途径,因此,本文将受力合理、塑性好、耐火性能优越的钢管混凝土柱作为研究对象,主要从爆炸冲击波的产生与传播、材料的动态力学性能、钢管混凝土柱在爆炸荷载作用下的动力响应和损伤评估等几个方面,系统地研究了钢管混凝土柱的抗爆性能,主要的研究内容和成果如下:(1)采用数值分析的方法模拟了爆炸冲击波产生与传播的整个过程,得到了网格尺寸对爆炸冲击波超压峰值的影响规律,验证了爆炸相似律的适用性,并分析了刚性地面对爆炸冲击波传播的影响。研究结果为爆炸冲击波的准确模拟提供了一定的依据:爆炸超压峰值对网格尺寸的敏感度随着比例距离的增大而减小;当缩尺比例较小时,在比例距离较小的情况下,爆炸相似定律的误差较大;爆炸冲击波超压峰值会因刚性地面的反射作用而显著增大,但这种增强效应会随着起爆高度的增大而减弱,当起爆高度增大到一定数值时,这种增强效应就可以被忽略。(2)采用分离式霍普金森压杆(SHPB)试验的数值模型分别研究了单轴应力状态下混凝土、钢材、钢管混凝土的动态力学性能和被动围压下混凝土的动态力学性能,并分析了HJC模型参数的敏感性。研究结果可为爆炸荷载作用下钢管混凝土柱数值模型的建立提供一定依据:混凝土、钢材和钢管混凝土都是应变率敏感材料,材料强度随着应变率的增大都有一定程度的提高;HJC模型适用于模拟各种受力状态下混凝土的动态力学性能;可根据HJC模型参数的敏感性来修正数值模型;钢管与混凝土之间的粘结滑移对钢管混凝土的动态力学性能影响不大。(3)采用等效单自由度分析方法,求解了不同截面形式的钢管混凝土柱在爆炸荷载作用下的最大动力位移。与试验结果比较显示,简化的理论分析方法能很好地求解整个动力过程的最大动力响应,而且当材料用量相同时,圆形截面钢管混凝土柱的抗爆性能要优于方形截面钢管混凝土柱。(4)采用流固耦合的方法建立了钢管混凝土柱在爆炸荷载作用下的数值模型,并根据试验数据对模型参数进行修正,研究了钢管混凝土柱的动力响应和破坏模式,分析了影响其抗爆性能的因素,并基于竖向剩余承载力损伤评估准则建立了压力-冲量曲线(P-I曲线)图。结果表明,在爆炸荷载作用下,钢管混凝土柱整体变形较好,且充分发挥了钢材和混凝土两种材料的特性,抗爆性能优越;近场爆炸时,钢管混凝土柱趋向于发生局部破坏,而远场爆炸时,钢管混凝土柱趋向于发生整体破坏,且其破坏模式与超压峰值和冲量的大小有关;轴压比、柱高和比例距离对钢管混凝土柱的抗爆性能具有显著影响,材料强度等级、含钢率、截面形式等因素也具有一定的影响;竖向剩余承载力损伤评估准则与钢管混凝土柱的破坏模式无关,可以有效反映爆炸荷载作用下钢管混凝土柱的破坏程度。
[Abstract]:With the change of the target of terrorist attack and the increase of the explosion of natural gas, it is necessary to consider the explosion load properly in the design of civil architecture. The material and structure system with excellent anti-explosion performance is the most effective and most economical way of anti-explosion design. Therefore, the steel pipe concrete column with reasonable stress, good plasticity and excellent fire resistance is used as the research object, mainly from the generation and propagation of the blast shock wave. The dynamic mechanical property of the material, the dynamic response of the steel tube concrete column under the action of explosion load and the damage assessment have been studied systematically. The main research contents and results are as follows: (1) The numerical analysis method is used to simulate the whole process of the generation and propagation of the blast shock wave, and the influence of the grid size on the peak of the blast shock wave overpressure is obtained, the applicability of the explosion similarity law is verified, and the influence of the rigid ground on the propagation of the explosion shock wave is analyzed. The results of the study provide a basis for the accurate simulation of the blast shock wave: the sensitivity of the peak to the size of the explosion is reduced with the increase of the proportion distance, and when the scale is small, the error of the similar law of the explosion is larger. The peak of the overpressure of the blast shock wave can be obviously increased due to the reflection of the rigid ground, but the enhancement effect can be weakened with the increase of the initiation height, and the enhancement effect can be ignored when the initiation height is increased to a certain value. (2) The dynamic mechanical properties of concrete, steel, steel tube concrete under single-axis stress state and the dynamic mechanical properties of concrete under the passive confining pressure are studied by using the numerical model of the split Hopkinson pressure bar (SHPB) test, and the sensitivity of the parameters of the HJC model is also analyzed. The results of the study can provide a basis for the establishment of the numerical model of the steel tube concrete column under the action of the explosion load: the concrete, the steel and the steel pipe concrete are both strain rate sensitive materials, and the strength of the material increases with the increase of the strain rate; The HJC model is suitable for simulating the dynamic mechanical property of the concrete under various stress states; the numerical model can be modified according to the sensitivity of the parameters of the HJC model; and the influence of the bonding slip between the steel pipe and the concrete on the dynamic mechanical property of the steel pipe concrete is not large. (3) The equivalent single-degree-of-freedom analysis method is adopted to solve the maximum dynamic displacement of the steel tube concrete column in different sections under the action of explosion load. Compared with the test results, the simplified theoretical analysis method can well solve the maximum dynamic response of the whole power process, and when the material is used in the same amount, the anti-explosion property of the circular cross-section steel tube concrete column can be better than that of the square-section steel tube concrete column. and (4) the numerical model of the steel tube concrete column under the action of explosion loading is established by adopting a flow-solid coupling method, the model parameters are corrected according to the test data, the dynamic response and the failure mode of the steel tube concrete column are researched, the factors influencing the anti-explosion performance of the steel tube concrete column are analyzed, and a pressure-impulse curve (P-I curve) graph is established based on the vertical residual bearing capacity damage evaluation criterion. The results show that, under the action of explosion load, the whole deformation of the steel tube concrete column is good, and the properties of both the steel and the concrete are fully exerted, and the anti-explosion performance is superior; in the near field explosion, the steel tube concrete column tends to be partially destroyed, and the far field explosion, The steel tube concrete column tends to be destroyed as a whole, and its failure mode is related to the magnitude of the overpressure peak and the impulse; the shaft pressure ratio, the column height and the proportional distance can have a significant influence on the anti-explosion performance of the steel tube concrete column, the material strength grade, the steel-containing rate, The cross-sectional form and other factors also have a certain influence; the damage evaluation criterion of the vertical residual bearing capacity is independent of the failure mode of the steel pipe concrete column, and the damage degree of the steel pipe concrete column under the action of the explosion load can be effectively reflected.
【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU398.9;TU311.3
本文编号：2378194
[Abstract]:With the change of the target of terrorist attack and the increase of the explosion of natural gas, it is necessary to consider the explosion load properly in the design of civil architecture. The material and structure system with excellent anti-explosion performance is the most effective and most economical way of anti-explosion design. Therefore, the steel pipe concrete column with reasonable stress, good plasticity and excellent fire resistance is used as the research object, mainly from the generation and propagation of the blast shock wave. The dynamic mechanical property of the material, the dynamic response of the steel tube concrete column under the action of explosion load and the damage assessment have been studied systematically. The main research contents and results are as follows: (1) The numerical analysis method is used to simulate the whole process of the generation and propagation of the blast shock wave, and the influence of the grid size on the peak of the blast shock wave overpressure is obtained, the applicability of the explosion similarity law is verified, and the influence of the rigid ground on the propagation of the explosion shock wave is analyzed. The results of the study provide a basis for the accurate simulation of the blast shock wave: the sensitivity of the peak to the size of the explosion is reduced with the increase of the proportion distance, and when the scale is small, the error of the similar law of the explosion is larger. The peak of the overpressure of the blast shock wave can be obviously increased due to the reflection of the rigid ground, but the enhancement effect can be weakened with the increase of the initiation height, and the enhancement effect can be ignored when the initiation height is increased to a certain value. (2) The dynamic mechanical properties of concrete, steel, steel tube concrete under single-axis stress state and the dynamic mechanical properties of concrete under the passive confining pressure are studied by using the numerical model of the split Hopkinson pressure bar (SHPB) test, and the sensitivity of the parameters of the HJC model is also analyzed. The results of the study can provide a basis for the establishment of the numerical model of the steel tube concrete column under the action of the explosion load: the concrete, the steel and the steel pipe concrete are both strain rate sensitive materials, and the strength of the material increases with the increase of the strain rate; The HJC model is suitable for simulating the dynamic mechanical property of the concrete under various stress states; the numerical model can be modified according to the sensitivity of the parameters of the HJC model; and the influence of the bonding slip between the steel pipe and the concrete on the dynamic mechanical property of the steel pipe concrete is not large. (3) The equivalent single-degree-of-freedom analysis method is adopted to solve the maximum dynamic displacement of the steel tube concrete column in different sections under the action of explosion load. Compared with the test results, the simplified theoretical analysis method can well solve the maximum dynamic response of the whole power process, and when the material is used in the same amount, the anti-explosion property of the circular cross-section steel tube concrete column can be better than that of the square-section steel tube concrete column. and (4) the numerical model of the steel tube concrete column under the action of explosion loading is established by adopting a flow-solid coupling method, the model parameters are corrected according to the test data, the dynamic response and the failure mode of the steel tube concrete column are researched, the factors influencing the anti-explosion performance of the steel tube concrete column are analyzed, and a pressure-impulse curve (P-I curve) graph is established based on the vertical residual bearing capacity damage evaluation criterion. The results show that, under the action of explosion load, the whole deformation of the steel tube concrete column is good, and the properties of both the steel and the concrete are fully exerted, and the anti-explosion performance is superior; in the near field explosion, the steel tube concrete column tends to be partially destroyed, and the far field explosion, The steel tube concrete column tends to be destroyed as a whole, and its failure mode is related to the magnitude of the overpressure peak and the impulse; the shaft pressure ratio, the column height and the proportional distance can have a significant influence on the anti-explosion performance of the steel tube concrete column, the material strength grade, the steel-containing rate, The cross-sectional form and other factors also have a certain influence; the damage evaluation criterion of the vertical residual bearing capacity is independent of the failure mode of the steel pipe concrete column, and the damage degree of the steel pipe concrete column under the action of the explosion load can be effectively reflected.
【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU398.9;TU311.3
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