【作者】 张凤华；

【导师】 赵均海；

【作者基本信息】 长安大学 ， 结构工程， 2007， 硕士

【摘要】 当前和平与发展是时代的主旋律,但是在和平的旋律中存在着一些不稳定的因素,那就是恐怖主义。随着恐怖主义的蔓延,炸药爆炸这种手段越来越多被恐怖分子所利用,这种爆炸恐怖活动对国际社会的和平与安宁造成了巨大威胁,成为危害国家安全和社会稳定的主要因素。除了恐怖袭击引起的爆炸以外,还有燃气爆炸、工业生产中的突发爆炸等意外事件,所以对爆炸防护设计原理及技术措施的研究是一个现实而迫切的课题。研究结构在爆炸冲击荷载下的破坏分析是防爆抗爆的一个重要领域。现在对于各种突发性爆炸冲击荷载下,有效地设计和防护结构或构件的研究还没有一套完整的理论,还需要不断的探讨和研究。本文主要对爆炸冲击荷载作用下钢筋混凝土墙体的动力响应进行了理论计算和数值模拟。主要工作是对简化为倒三角形形式的爆炸荷载作用下的钢筋混凝土墙体,采用等效单自由度体系的近似设计法,按照四边固支的双向板的理论,求出其最大动力位移;然后基于大型有限元分析软件ANSYS9.0中的显式动力分析模块LS-DYNA对承受爆炸冲击荷载的钢筋混凝土墙体进行三维有限元模拟,有限元中能够直接对墙体来模拟,而不是作为板来考虑;通过动力分析,得出四边固支墙体的最大变形和随时间的响应变化过程,并且和理论计算结果作比较,吻合的较好,说明对于墙体按照近似设计法的双向板理论来分析的正确性和合理性,及有限元模拟中选用96号材料模型的正确性;最后应用有限元数值模拟的有利条件对影响墙体动力响应的各因素进行了分析,主要分析了边界约束条件、配筋率、墙体厚度、混凝土强度、冲击荷载的峰值和作用时间等因素对钢筋混凝土墙体动力响应的影响,得出以下结论:1.用等效单自由度体系的近似设计法对钢筋混凝土墙体进行理论分析,运用四边固支板的参数,对倒三角形形式的冲击荷载作用下的钢筋混凝土墙体的动力响应进行分析,得出墙体的最大位移为41.5mm。2.对钢筋混凝土墙体,运用有限元软件ANSYS/LS-DYNA建立整体式模型,采用三维实体单元SOLID164和material-brittle-damage材料模型,对理想化爆炸冲击荷载作用下的墙体进行数值模拟,得出了墙体在不同时刻的响应。有限元分析结果表明墙体最大位移为51mm,比近似设计结果41.5mm大9.5mm,吻合的较好,验证了理论结果的正确性,和数值模拟物理模型的可靠性。3.对不同边界条件、不同配筋率、厚度、混凝土强度和爆炸荷载峰值、爆炸荷载作用时间作用下的钢筋混凝土墙体进行了动力模拟,得到墙体中心点的位移时程曲线。结果表明,增加厚度,提高配筋率,采用高标号混凝土,加强边界条件的约束都可以提高钢筋混凝土墙体的抗爆炸冲击能力,其中增加厚度是最有效的一个措施。随着爆炸荷载峰值的增大、爆炸荷载作用时间的增长,位移和应力响应都有所增大。更多还原

【Abstract】 Terrorism occurs frequently although nowdays peace and development are the mainstream of modern society. The explosion events occurs more frenquently than other terrorist events. The terrorism have threaten the peace of the whole world, so it is the main factor of endanger the security of many countries. Besides explosion brought by the terrorism, there are other explosive accidents, such as explosion of gas, blast of industrial production. Research on the theory and the technology protecting the structure from the blast is a practical and urgent subject. The dynamic response analysis of structure under explosive and impact loads is an important field. Nowadays, the theory on resisting explosive load for structure is incomplete, so it needs further discussion and study.Dynamic response analysis of reinforced concrete wall under explosive or impact loads were investigated by theoretical method and numerical method in this paper. The largest dynamic displacement of reinforced concrete wall was deduced by adopting the parameter of bidirectional slab with the four sides fixation based on approximately design method of equivalent single-degree-of-freedom system; The dynamic response of the reinforced concrete wall under explosive or impact loads is simulated using the software ANSYS-LS-DYNA, The 3-D model of the reinforced concrete wall was set up in ANSYS-LS-DYNA. The curves of largest displacement versus time of the wall with four sides fixting were obtained from the results of numerical simulation. The numerical results agree well with that of the theoretical method. It indicates that the theory of bidirectional slab with the four sides fixation applying to analysis of the wall is accurate and reasonable. And the parameters of the material model 96 are reliable in the finite element model. In the end, by taking advantage of the numerical simulation, a lot of factors affecting the dynamic response of wall are analyzed, such as boundary conditions, ratio of reinforcement, thickness of wall, strength of concrete, and peak value and duration of the explosive load etc. Some conclusions can be obtained as follows:1. Basing on approximately design method of equivalent single-degree-of-freedom system, dynamic response of reinforced concrete wall under right-angled triangle form of explosive or impact loads are analyzed by adopting the parameter of bidirectional slab with the four sides fixation, and the largest displacement of wall obtained is 41.5mm. 2. The finite element model of reinforced concrete wall was set up by adopting the explicit dynamic analysis module LS-DYNA of the large finite element software ANSYS9.0. Dynamic response of reinforced concrete wall under right-angled triangle form of explosive or impact loads were simulated, in which SOLID 164 element and material-brittle-damage were adopted. The dynamic response of the wall were obtained., and the largest displacement of wall is 51mm, which is larger than 41.5mm obtained from theoretical. The results indicate that the theory of bidirectional slab with the four sides fixation applying to analysis of the wall is accurate and reasonable and the parameters used in the 96 material model is reliable.3. Dynamic response of reinforced concrete wall with different supported condition, reinforced ratio, thickness, concrete strength, peak value and time of explosive or impact loads was obtained. The results indicate that the thickness of the wall, the reinforced ratio, concrete strength, boundary conditions have significant influence on the resisting ability of wall under explosive or impact loads. The thickness of the wall has the most important effects on the resisting ability. The displacement increases with the peak value of the pressure and the duration of the time.更多还原