2076平米四层框架住宅楼 zmr英文翻译

东南大学成贤学院 毕业设计英文翻译Damage Model Based Reinforced-Concrete Element损伤模型为基础的钢筋混凝土构件Chee Kiong Soh1; Yu Liu2; Yue Xing Dong3; and Xin Zheng Lu4Abstract: In this paper, the damage in concrete around a reinforcement bar is examined, and three types of damage in concrete and at the concrete-rebar interface are defined. Based on these definitions, a three-dimensional damaged reinforced-concrete DRC! element is proposed. The element consists of a 10-node concrete element, a two-node rebar element, and a four-node concrete-rebar interfaceelement. Experiments were carried out to obtain the parameters for the bond damage evolution equation. The proposed DRC element is implemented as a user-defined element of MSC MARC2000, a commercial finite-element analysis software package. Two numerical examples were examined, and the results show that the DRC element can simulate the bond deterioration in reinforced-concrete structural members with sufficient rationality, accuracy, and efficiency.DOI: 10.1061/ASCE15:4371!CE Database subject headings: Damage; Models; Concrete, reinforced.摘要：在本论文中，讨论了加强钢筋周围的混凝土的破坏情况，将混凝土钢筋破坏界面的界定为3种类型。根据这些定义，提出了高强混凝土的三维破坏原理。这个原理包含三个元素，分别是一个10节点的混凝土构件，两节点筋单元，和一个四节点的混凝土钢筋接口。进行了试验，以取得弯矩破坏公式的有关参数。数据控制记录被建议作为MSC MARC2000的一个用户定义元素，MSC MARC2000是一个商用有限元分析软件包。两个数值实例研究结果表明，数据控制记录元素可以合理精确有效的模拟高强混凝土黏结失效。DOI: 10.1061/ASCE15:4371!CE数据库主题词：破坏;模型;混凝土，加固。IntroductionIn the design and analysis of reinforced-concrete structures,the bond between the reinforcement bar and concrete is one of the important factors that must be properly accounted for.The shear bond, in particular, is the main load-carrying mechanism between the concrete and its reinforcement in the longitudinal direction of the rebars. Although perfect bonding can be assumed when little or no stress transfer occurs between the concrete and rebar, slip at the concrete-rebar interface usually occurs when reinforced-concrete structures are loaded, especially in cases when high stress at the contact interface and at the end anchorage exists. It has been shown that it is essential to include bond-slip in the analysis of reinforced-concrete structures. The bond stress is directly related to the slip of the interface.The behavior of the interface will deteriorate after the slip reaches a certain level, and as a result of damage development nonlinear and softening behavior will appear in the bond stress-slip curves. These must be fully simulated in the reinforced concrete structure analysis. While the various bond problems can be treated separately using contact elements or interface elements，it is not easy to take into account the interaction between the cracking of concrete and the bond deterioration of the concrete-rebar interface. At the same time, these concrete interface-rebar meshing techniques usually need many elements in the finite-element analysis for accurate results to be obtained.导言在设计和分析高强混凝土结构中，巩固钢筋混凝土之间的黏结是最主要因素之一，剪切粘固力尤其是主要的承载机制之间的混凝土及其加固中的纵向方向的钢筋。当混凝土和钢筋很少或没有应力传递发生关系时，虽然完美的结合可以假定，但当钢筋混凝土结构有荷载时，尤其是在接触面上和端部锚具存在压力比较大时，在钢筋混凝土接口处通常发生滑移。已经表明它是必不可少的，包括在分析钢筋混凝土结构的滑移。黏结力是直接关系到接触面上的滑移。当下滑到一定程度时接触面性能就会变差 ，因而损害非线性与性能软化出现的滑动应力曲线的发展， 这些必须有充分的模拟在混凝土结构分析中。而各种黏结的问题可以分开处理，采用接触单元或界面元素，这是一个不太容易顾及互动，混凝土裂缝和黏结失效的混凝土钢筋界面。与此同时，这些混凝土界面-钢筋网格化技术通常需要许多要素，在有限元分析，为准确的结果，以期获得。In this paper, a 12-node 3D damaged reinforced-concrete element is developed based on the damage description of the concrete and the bond properties on the concrete-rebar interface.In this DRC element, the damage in the concrete and on the concrete-rebar interface is considered using three damage variables,so that the nonlinear and softening behavior of the concrete and the interface can be realistically modeled. Experiments were carried out to obtain the parameters for the bond damage evolution equation. The DRC element developed is implemented as a user-defined element in a commercial FEA package, MSC MARC2000. Two numerical examples are given to illustrate the effectiveness of the DRC element in analyzing reinforced-concrete specimens. The results show that the DRC element can simulate the bond deterioration in RC structural members with sufficient rationality and accuracy. However, the model is still too simple to deal with the complexity of real structures, and the limitations of the DRC element and required further work are discussed.在本文中，一个12节点的三维受损钢筋混凝土构件的主要因素是建立在钢筋混凝土界面上描述混凝土损害与黏结性能的基础上的。这个数据控制记录元素在混凝土及钢筋混凝土界面上的损伤，被认为是用3个损伤变量，所以说，非线性和软化性能的混凝土与接口，在现实中可以仿照。进行了试验，以取得黏结损伤演化方程的参数。弄好的数据控制记录元素在一个商业有限元分析软件包MSC MARC2000中作为用户定义的元素被应用。在分析钢筋混凝土标本时两个数值例子说明了数据控制记录的成效性。结果表明，数据控制记录元素可以模拟在钢筋混凝土构件黏结性降低，有足够的合理性和准确性。然而，这个模式仍然过于简单去处理复杂的实际结构，以及数据记录控制元素的有限性和必须的进一步的工作进行探讨。Reinforced-Concrete Element with Damage DescriptionIn the 12-node 3D reinforced-concrete element developed, the concrete and the bond behavior of the concrete-rebar interface are described using damage mechanics. Thus, the element is called a damaged reinforced-concrete element or DRC element, in short. The DRC element consists of a 10-node brick element for the concrete, a two-node rod element for the rebar, and a four-node interface element for the interface between the concrete and rebar.One additional deformation mode of the concrete is introduced to account for the shear deformation of concrete due to the bond stress at the interface between the rebar and the concrete. Theforce-displacement relation of the additional deformation mode is deduced using the principle of virtual work. Two scalar-damage variables, Db and Dn , are introduced to describe the bond deterioration of the rebar-concrete interface and the cracking of the concrete. The derivation of the DRC element is explained in detail later.钢筋混凝土构件损伤描述在12个结点的三维钢筋混凝土构件的发展中，混凝土与钢筋混凝土界面上的粘结性能被描述为损伤力学。因此，构件可简称为受损钢筋混凝土构件或数据记录控制元素。数据控制记录元素由一个10节点单元砖混结构，两节点钢构件和一个四节点接口单元之间的混凝土与钢筋界面组成。增设一个混凝土模型变形的具体介绍，说明在钢筋和混凝土界面上由于黏结应力使得混凝土剪切变形。额外变形模式的力位移关系，推导出利用虚功原理。两个损伤标量的变量， DB和DN，是引进来形容钢筋与混凝土界面的黏结降低和混凝土的开裂。推导了的数据记录控制元素被详细的解释了。Affected Zone and Local DamageAn affected zone is a volume of concrete around a deformed rebar in which local damage of concrete occurs as a result of the wedge action around the rebar, as shown in Fig. 1. As shown later, besides the deformation of the rebar, the deformation modes in the DRC element consist of the deformation modes of an eight-node isoparametric element, an additional shear deformation mode, and a slip mode at the concrete-rebar interface. Accordingly, three kinds of damage in the DRC element are identified, which are the local damage Dl in the affected zone of the concrete, the nonlocal damage Dn in the concrete, and the bond damage Db at the rebarconcrete interface. The local damage in the affected zone of the concrete is attributed to the additional deformation mode and the wedge action. The nonlocal damage in the concrete is attributed to the deformation modes of the eight-node isoparametric element. The bond damage indicates the deterioration of bond stiffness of the concrete-rebar interface because of the slip and wedge action around the rebar. For simplification, Dl , Dn and Db are all assumed to be scalars. Of the three kinds of damage, the local damage Dl is closely related to the bond damage Db because they are due to wedge action around the rebar. So for simplification, the local damage Dl is assumed to be proportional to the bond damage Db ; i.e. where parameter that needs to be calibrated in the DRC element.影响区和局部损伤一个影响区是由于该楔形活动遍布钢筋，一个混凝土体积周围钢筋在混凝土发生局部损伤时变形，如图1所示。显示后，除了钢筋变形，由一个八节点等参元构成的数据记录控制元素的模型变形，附加剪切模型变形，和在钢筋混凝土界面滑移模型。因此，在数据记录控制元素下的三种损害：影响区的混凝土局部损伤Dl，混凝土的非局部损伤Dn和在钢筋混凝土界面上的黏结降低Db是确定的。影响部分混凝土的局部变形归功于以附加变形模式和裂开行为。混凝土非局部损伤归结为变形模式的八节点等参数。由于钢筋滑动和开列行为，黏结性能降低表明钢筋混凝土界面的黏结刚度恶化。为简化，Dl , Dn和Db都是假设标量。造成损害的有三种，局部损伤Dl是密切相关黏结降低性的，因为钢筋的滑动和开列行为。如此简化，局部损伤Dl被假设为按比例的黏结损害Db，例如Dl= aD b(1)即当在数据记录控制的元素下参数需要加以校正。Additional Deformation Mode of Concrete in Damaged Reinforced-Concrete ElementTo consider the shear deformation of the concrete around the rebar, an additional deformation mode in the affected zone is introduced, as shown in Fig. 2. The affected zone is assumed to be a concrete cylinder that is fixed at its rim and subjected to a force FA along the x-axis on one end surface. The longitudinal axis of the cylinder is assumed to be the x-axis. Hence, in the r-u-x coordinate system, the displacement field u(x,r) can be assumed to be u(x,r)=1(1-)(1-) (2)where R=radius of the affected zone; Rs=radius of the rebar; l =length of the concrete cylinder; and =displacement of the interface relative to the rim at the loaded end of the DRC element. According to the theory of elasticity, the idealized strain field can be derived as =-（R-r） ； =-（1-）;其他的为0 （3） ；and the stress fields are ； ； ；其他为0 （4）where Ec and =elastic modulus and Poissons ratio of the virgin concrete, respectively.According to the principle of virtual work, the following equation can be written: （5） where; and virtual displacement. From Eqs. （4） And （5）, the force-displacement relations can be derived as （6）附加混凝土变形模型受损钢筋混凝土构件考虑混凝土周围的钢筋剪切变形，另外在影响区的变形模型被介绍，如图所示，如图 2 。受影响地区被假定为一个在边缘混合和遭受了一个沿端面X轴的力F混凝土拄体。纵向轴的圆筒，假设为X轴。因此，在r-u-x坐标系中，场铀位移u(x,r) 可以假设为u(x,r)=1(1-)(1-) (2) R=半径的影响区,Rs =半径钢筋;L =钢筒混凝土的长度; =在无荷载数据记录控制元素的相关边缘的位移。 根据该理论的弹性，理想化的应变场，可以推导出=-（R-r） =-（1-）;其他的为0 （3）应力场是； ；其他为0 （4）；而Ec和分别为素混凝土的弹性模量和泊松比。 根据对等原则的虚拟工作，提出了以下方程，可以这样写： （5） 其中；和虚位移。从公式（4）和（5）力位移关系可以推导为 （6）Bond Damage on Concrete-Rebar InterfaceAn accepted practice in dealing with the bond problem is to assume that the shear stress is a function of the slip of the interface with a damage factor included in the expression to take into account the degradation of the bond. The relationship between the bond stress and slip of the concrete-rebar interfaceis assumed to be （7） where Eb=virgin bond stiffness; Db=mean bond damage in the DRC element; and =slip along the rebar. In Eq.（7）, it is assumed that the bond behavior would deteriorate only when slip develops, but according to experimental observation the cracking of concrete will also affect the bond behavior. To account for this effect, a bond stress-slip relation is thus assumed (8) where parameter is related to the length of the DRC element, l. Maekawa and Qureshi assumed that the bond stress decreases to zero within a distance of 2.5ds from the cracking plane (ds is the diameter of the rebar), as shown in Fig. 3; so when l5ds , we assume that 1. A linear slip field is assumed for the DRC element, which can be written as （9） where and =slip at the two ends of the DRC element, as shown in Fig.（4）. The bond forces at the ends of the DRC element can then be calculated by ； （10） Eq. （10） can be used to determine experimentally the evolution equation of the bond damage Db . For example, when a rebar is pulled out from the concrete, the pullout force, Fp , can be derived from Eq. （10） to be （11） Thus, the relationship between the bond damage Db and the slip can be determined if the pullout force Fp and the slip on the two surfaces, and , can be measured and if it is ensured that Dn=0 in the experiment.钢筋混凝土的黏结损失在处理黏结问题的一个公认惯例是：假设剪应力为一个滑坡界面的损伤函数，包括表现描述为黏结性降低。黏结应力和钢筋混凝土界面的滑移关系假设为： （7） 其中E=钢筋黏结刚度；=在数据记录控制元素中的黏结损失；=沿钢筋的滑动。在公式（7）中，只有当滑移发生时，它被假定为黏结性能降低，但据实验观察混凝土的开裂，也会影响到黏结性能。考虑到这一效应，因此假设黏结应力滑移关系为： （8）如果参数与元素数据记录控制长度有关，l. Maekawa和Qureshi假定黏结力在2.5d的范围内在开裂阶段下降到0，如图所示，所以当我们将假设1。 假设数据记录控制构件成下滑线性趋势，可以写为 （9）和为数据记录控制构件两端的滑移度，如图4（a）所示，数据记录控制构件末端的黏结力可以由如下公式推出：； （10） 公式（10）可以用来检验实验上的黏结降低的Db公式，例如当钢筋从混凝土中露出来时拔出力Fp可以由公式（10）推导为 （11）。 因此，如果Fp和界面的滑移可以确定，实验可以证明Dn=0，黏结降低Db和裂缝间的关系可以确定下来。Nonlocal Damage in ConcreteThe nonlocal damage in concrete, Dn , in this paper refers to the degradation and cracking of concrete not directly induced by the bond damage or wedge action on the concrete-rebar interface. It occurs not only in the reinforced-concrete element, but also in the pure concrete element, and in the DRC element it is due to the deformation modes of the common eight-node isoparametric element of the concrete.For simplification, a scalar damage model for concrete is adopted, with the stress-strain relationship defined as （12） where and stress and strain vector, respectively; D=elastic matrix; and Dn=damage scalar defined as （13） where E(0)=softening module; f t=tensile strength of the concrete; and =maximum principal stress when the concrete is assumed to be an elastic material; that is （14） where =principal strains. For the one-dimensional cases, this model gives a stress-strain curve as shown in Fig. 5, which is the same as those given by the crack band model with a linear softening phase. But this model, described using damage mechanics, makes it easier to consider the interaction between the concrete cracking and the bond deterioration, as shown in Eq. （8）.混凝土的整体破坏 在本篇论文中，由混凝土的开裂和变形引起的整体破坏的Dn不是直接由钢筋表面的黏结破坏得出的，他的出现不仅发生在钢筋混凝土构件上，而且在素混凝土上也会发生。数据记录