爆炸作用下钢筋混凝土板的塑性动力响应

发布时间：2018-04-14 04:27

本文选题：钢筋混凝土矩形板 + 刚塑性　；参考：《哈尔滨工程大学》2014年硕士论文

【摘要】：由于爆炸对结构的作用时间短、荷载幅值大,分析结构在爆炸作用下的完整过程是复杂且繁重的工作。板作为常用的抗爆构件,研究其在爆炸作用下的动力响应对于结构抗爆研究具有实际工程意义。本文以能量法和塑性理论为基础,采用理论分析与数值模拟两种方法,对爆炸作用下钢筋混凝土矩形板的动力响应进行研究,主要研究内容如下:1、将钢筋混凝土简化为完全刚塑性材料,以能量法和塑性铰线理论为基础,构造出刚塑性矩形板的极限状态塑性铰线,塑性铰线形成的塑性破坏机构有两种,分别列出其小变形情况的运动平衡方程。2、由于板在爆炸荷载作用下通常产生大变形,边界支撑条件的约束会限制大变形的发展,将这种约束简化为作用在板中面的反作用力,所以称这种现象为面力效应或膜力效应。根据最大耗散能原理计算塑性铰线能量耗散功率时,考虑中面膜力的作用,引入膜力因子,定义大变形时边界支撑的有利作用。3、将板的变形分为大变形和小变形两种情况,在小变形方程中引入膜力因子,即构成大变形动力平衡方程。在简化的三角形爆炸荷载作用下,根据板的变形挠度的大小和两种塑性变形机构建立不同的平衡方程,解出了在中载和高载情况下刚塑性矩形板的完整动力响应过程。4、选取合理的数值分析方法,利用显式动力有限元软件ANSYS/LS-DYNA对爆炸作用下钢筋混凝土矩形板的动力响应进行数值分析。结果表明,炸药当量对板产生弹性或塑性变形起决定作用;板的配筋率越低,则板的塑性变形越明显;混凝土的强度对板的破坏形式影响不大;随着边界约束的增多,板受到的面力效应的影响,抗弯刚度增强。5、数值分析同时表明,钢筋混凝土矩形板的破坏模式也呈现两种形式,与本文理论分析结果相近,且符合理论分析的刚塑性假设、塑性铰线理论和膜力效应的应用条件,可以采用本文理论方法利用数值手段分析钢筋混凝土板在爆炸作用下的变形和破坏。
[Abstract]:Because of the short time of explosion and the large amplitude of load, it is complicated and arduous to analyze the whole process of structure under explosion.As a commonly used anti-explosion member, it is of practical engineering significance to study the dynamic response of plate under explosion.Based on the energy method and plastic theory, the dynamic response of reinforced concrete rectangular slab under explosion is studied by theoretical analysis and numerical simulation.The main research contents are as follows: 1. The reinforced concrete is simplified as a completely rigid-plastic material. Based on the energy method and the plastic hinge theory, the limit state plastic hinge line of the rigid plastic rectangular plate is constructed. There are two kinds of plastic failure mechanisms formed by the plastic hinge line.The equation of motion balance of small deformation is listed separately. Because the plate usually produces large deformation under the action of explosion load, the constraint of boundary bracing condition will limit the development of large deformation, so the constraint is simplified as the reaction force acting on the middle surface of the plate.Therefore, this phenomenon is called surface force effect or membrane force effect.According to the principle of maximum dissipation energy, when calculating the energy dissipation power of plastic hinges, considering the effect of midface membrane force, introducing the membrane force factor, defining the beneficial action of boundary bracing in large deformation, the deformation of plate is divided into two cases: large deformation and small deformation.The membrane force factor is introduced into the small deformation equation, that is, the large deformation dynamic equilibrium equation is constructed.Under simplified triangular explosive load, different equilibrium equations are established according to the deformation deflection of the plate and the two plastic deformation mechanisms.The complete dynamic response process of rigid-plastic rectangular plates under medium and high loads is solved. A reasonable numerical analysis method is selected.The dynamic response of reinforced concrete rectangular slab subjected to explosion is numerically analyzed by using explicit dynamic finite element software ANSYS/LS-DYNA.The results show that the explosive equivalent plays a decisive role in the elastic or plastic deformation of the plate; the lower the reinforcement ratio of the plate is, the more obvious the plastic deformation of the slab is; the strength of concrete has little effect on the failure form of the slab;Due to the effect of plane force, the flexural stiffness is enhanced. The numerical analysis also shows that the failure mode of reinforced concrete rectangular slab is also in two forms, which is close to the theoretical analysis results and accords with the rigid-plastic hypothesis of the theoretical analysis.The plastic hinge theory and the application condition of membrane force effect can be used to analyze the deformation and failure of reinforced concrete slabs under explosion by using the method of theory in this paper.
【学位授予单位】：哈尔滨工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU375.2

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