砌体填充墙抗爆性能的数值模拟

发布时间：2018-07-08 09:59

本文选题：砌体墙 + 手提箱包炸弹　；参考：《湖南大学》2015年硕士论文

【摘要】：砌体墙由于其良好的经济性在工程中得到了广泛应用。无论是作为砌体结构的主要受力部件,还是作为框架结构及框剪结构的填充部件,目前在我国仍然普遍使用。然而随着爆炸恐怖袭击事件的日益频发,相对于钢筋混凝土结构砌体墙表现出很强的脆性,高速爆炸冲击荷载下砌体墙破坏产生的碎片以很高的速度抛射,会给建筑的使用者造成严重的伤害。因此自9.11恐怖袭击事件以来,世界各国的政府和研究机构对砌体墙的抗爆问题进行了广泛而深入的研究。目前砌体墙在大中小城市主要作为钢筋混凝土结构的围护构件,因此研究其在爆炸冲击荷载作用下的抗爆性能显得尤为必要。近几十年来,计算机技术及有限元技术得到很大的发展,使得利用有限元软件进行结构抗爆分析成为可能。基于以上背景,本文采用ANSYS/AUTODYN软件对砌体填充墙进行大量的有限元模拟,同时结合砌体墙的落锤冲击试验来探究砌体墙抗爆的规律。本文以12墙、24墙及加固24墙为主要研究对象,并着重分析其动态响应规律,破坏过程演变及碎块抛射规律。本文完成的主要研究内容有:(1)采用有限元分析软件ANSYS/AUTODYN对近地面爆炸荷载作用下(不同比例距离作用下)砌体填充墙不同部位超压荷载分布情况进行研究分析,得出砌体墙在近距离地表爆炸作用下冲击荷载分布规律:数值模拟结果表明当距离较近时,爆炸冲击荷载在砌体墙表面分布极为不均匀,随着隔离距离的增大爆炸冲击荷载分布越来越均匀,此外发现增大爆距可以显著减小爆炸超压荷载。(2)对12墙,24墙,加固24墙进行近距离手提箱包炸弹作用下的抗爆数值模拟,以观察各砌体填充墙在爆炸冲击荷载作用下的动态响应和破坏规律。通过数值模拟可以发现在近距离手提箱包炸弹的爆炸荷载作用下,各砌体墙都会倒塌破坏,其破坏规律是一致的,但是破坏程度有差异。24墙及加固24墙相对12墙碎片抛射速度有较明显的降低。加固24墙由于聚氨酯加固膜的兜裹作用,最终会明显减小碎块的出墙面位移和速度,此外砌体墙各测点抛射速度与比例距离的关系曲线与超压峰值与比例距离关系比较相似。(3)对比砌体墙的落锤冲击试验和对试验的数值模拟的结果,发现砌体墙的破坏过程演变吻合性较好。但是落锤冲击试验的加载速率要明显比爆炸冲击加载速率慢一些。
[Abstract]:Masonry wall has been widely used in engineering because of its good economy. Whether as the main force component of masonry structure or as the filling part of frame structure and frame shear structure, it is still widely used in our country. However, with the increasing frequency of explosion terrorist attacks, compared with reinforced concrete structure masonry walls exhibit strong brittleness, the fragmentation of masonry walls under high velocity explosion impact load is ejected at a very high speed. Can cause serious damage to the users of the building. Therefore, since the September 11 terrorist attacks, governments and research institutions all over the world have carried out extensive and in-depth research on the anti-explosion problem of masonry walls. At present, masonry walls are mainly used as enclosing members of reinforced concrete structures in large, medium and small cities, so it is necessary to study the anti-explosion performance of masonry walls under blast impact loads. In recent decades, computer technology and finite element technology have been greatly developed, making it possible to use finite element software for structural anti-explosion analysis. Based on the above background, this paper uses ANSYS / AUTODYN software to carry on a large number of finite element simulation to the masonry infilled wall, at the same time combining with the drop hammer impact test of the masonry wall to explore the law of the masonry wall anti-explosion. In this paper, the dynamic response law, the evolution of the failure process and the law of fragmentation ejection are analyzed with emphasis on the dynamic response of 12 walls with 24 walls and 24 strengthened walls as well as the strengthening of 24 walls. The main research contents of this paper are as follows: (1) the distribution of overpressure loads in different parts of masonry infilled walls under blast loads near the ground (under different proportions of distance) is studied and analyzed by finite element analysis software ANSYS- AUTODYN. The distribution of impact load on the surface of masonry wall under the action of near surface explosion is obtained. The numerical simulation results show that the distribution of blast impact load on the surface of masonry wall is very uneven when the distance is close. With the increase of isolation distance, the distribution of blast impact load is more and more uniform. In addition, it is found that increasing the explosion distance can significantly reduce the explosive overpressure load. (2) numerical simulation of anti-explosion under the action of close-range suitcase bomb is carried out for 24 walls of 12 walls and 24 walls strengthened. In order to observe the dynamic response and failure law of each masonry filled wall under blast impact load. It can be found by numerical simulation that each masonry wall will collapse and destroy under the explosive load of a close distance suitcase bomb, and the failure law is consistent. However, there is a difference in the degree of failure between the 24 wall and the strengthened 24 wall. The velocity of shrapnel ejection from the 12 walls is obviously decreased. In the end, the displacement and velocity of the wall surface of the fragments will be significantly reduced because of the wrapping effect of the polyurethane reinforced film on the reinforced 24 walls. In addition, the relation curve between the ejection velocity and the proportional distance at each measuring point of the masonry wall is similar to the relationship between the peak value of overpressure and the proportional distance. (3) the results of drop hammer impact test and numerical simulation of the test are compared. It is found that the failure process of masonry walls is in good agreement with each other. But the loading rate of drop hammer impact test is obviously slower than that of explosion impact test.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU364;TU352.13

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