实干、实践、积累、思考、创新！ Tag: 结构工程博士 结构工程师 程序员 结构抗震设计 振动控制 光伏支架 加固改造 软件研发 编程 弹塑性 有限元 超高层 超限设计
Earthquake acceleration time history analysis in Abaqus (Abaqus地震加速度时程分析)。采用Abaqus的Standard求解器做个弹性框架结构的地震时程分析小例子，框架模型取用前面博文《Modal analysis of a frame using Abaqus (Abaqus框架模态分析)》模态分析中的框架结构，暂不讨论阻尼的作用，不考虑框架荷载和重力，输入单向地震波如下图所示，其中地震波按基底加速度的方式施加。
在传统的结构分析中，填充墙通常作为非结构构件考虑，在分析过程中，将其以外荷载的形式施加到结构上，并对整体结构的周期进行折减以考虑填充墙对结构刚度的贡献，未直接考虑填充墙对结构非线性行为的影响。相关研究表明[1,2]，填充墙对结构的抗震性能有着重要的影响，在结构弹塑性分析中，应合理考虑填充墙的影响。本章首先对砌体填充墙的抗震性能及填充墙的数值模型进行介绍，并着重介绍了基于等效斜压杆的填充墙宏观模型的参数计算方法，最后采用PERFORM-3D[3,4]对一单跨框架填充墙结构的低周往复加载试验进行模拟，讲解PERORM-3D中采用等效斜压杆填充墙模型进行框架填充墙模拟的基本步骤与参数设置方法。In traditional structural analysis, infilled wall is usually considered as non-structural element, and its effect to structure performance was only considered by applying equivalent external load to the main structure and reducing the structure period, the contribution of infilled wall to the structural nonlinear behaviour was not considered directly. Relevant studies have shown that infilled wall has significant influence on both linear and nonlinear structural performance. Therefore, infilled wall should be reasonably considered in structural elasto-plastic analysis. In this chapter, the seismic performance and numerical model of masonry infilled wall was firstly introduced, and the parameters calculation method of the macroscopic infilled wall model based on equivalent diagonal strut theory was explained in detail. After that, a PERFORM-3D simulation of low-cyclic reversed load test of a single span infilled frame structure was conducted by step by step, to explain the fundamental modelling process and parameter definition method of the equivalent diagonal strut infilled wall model.
集中塑性铰模型是梁、柱等杆系构件模拟中常用的一种模型。PERFORM-3D[1,2]中，塑性铰是一个截面组件（Component），通过将其与其他组件进行组装得到框架复合组件，用于模拟模拟梁、柱构件的非线性行为。PERFORM-3D包含两类塑性铰组件：弯矩型塑性铰（M铰）和弯矩-轴力相关型塑性铰（P-M-M铰），前者一般用来模拟截面轴力可以忽略的情况，比如梁端非线性行为，后者用来模拟截面轴力-弯矩相互作用的情况，比如柱端非线性行为。根据变形指标的不同，上述每种塑性铰又可以进一步分为转角型塑性铰（Rotation Type）和曲率型塑性铰（Curvature Type），前者用转角作为塑性铰变形的度量，后者用曲率作为塑性铰变形的度量。
PEEQ vs. PEMAG in ABAQUS ，ABAQUS中PEEQ和PEMAG的区别。PEEQ和PEMAG均是标量。PEMAG可能具有正负值，PEEQ具有累加性，取值大于或等于0，PEEQ大于0表示屈服。
Gravity Load in Abaqus (Abaqus中重力荷载的施加)
In order to establish the relation between damage state and member deformation of the L-section RC shear wall, 216 FE models designed to meet the requirements of the Chinese codes were set up. The analysis fully considers the variation of parameters including axial load ratio and shear span ratio etc. According to the results, criteria of classifying failure modes of L-section RC shear walls are proposed. Failure modes are determined by shear-span ratio, moment-shear ratio and end columns’ reinforcement ratio. Deformation limits corresponding to respective performance levels are put forward. Fitted formulas of calculating the limits are also presented. It is shown that the categorization criteria are reliably accurate in predicting failure modes. Deformation limits of a given L-section RC shear wall could be determined via axial load ratio and moment-shear ratio. The fitted formulas possess a satisfactory correlation with numerical results.
ANSYS 影响线分析。(Influence line analysis using ANSYS)
TABLE type array parameters in ANSYS (ANSYS中的表格型数组参数)
ANSYS中的数组参数是APDL语言中十分重要的参数，在定义材料参数、施加荷载及定义分析工况等时候都会用到数组来储存数据，通过几个命令流来学习ARRAY的基本语法。从以上例子可见，ANSYS中的ARRAY数组是按列来赋值的。
ANSYS 框架结构模态分析练习。(This is a small example to outline the steps required to do a simple modal analysis of a frame structure using ANSYS.)
复习固体力学知识。St. Venant-Kirchhoff Material 是经典的超弹性材料。
Abaqus框架结构模态分析练习。(This is a small example to outline the steps required to do a simple modal analysis of a frame structure using Abaqus.)
整理对数应变和工程应变的知识。从以上关系可以看出，真实应力比名义应力大，对数应变比名义应变大，当应变比较大时，两者差异会很大。另外，对数应变还具有可比性，可加性，这些都是名义应变所不具有的。以利用上述关系，可将名义应力应变关系转换为真实应力应变关系。
稳态热传导的控制方程与经典扭转理论的控制方程具有相似性。我们可以通过比拟，在通用有限元软件中利用稳态热传导分析的功能进行扭转问题的分析。本文结合Abaqus软件，通过一个实例说明这个比拟的具体过程。(The steady heat conduction problem and the classic torsion theory have analogy in their control partial differential equations. We can conduct a torsional analysis making use of the steady analysis fuction in general finite element program. This post gives an example on how to do torsion analysis as thermal analogy with Abaqus.)
稳态热传导控制方程与扭转控制方程具有相似性。利用ANSYS中的稳态热传导分析功能通过比拟的方法进行截面的扭转应力分析。The steady heat conduction problem and the classic torsion theory have analogy in their control partial differential equations. We can conduct a torsional analysis making use of the steady analysis fuction in general finite element program.This post gives an example on how to do torsion analysis as thermal analogy with ANSYS.
欧拉伯-努利梁理论（Euler–Bernoulli beam）又称为工程梁理论（Engineering beam theory）或者经典梁理论（Classical beam theory）。欧拉梁不考虑剪切变形，与铁木辛柯梁（Timoshenko beam）相对。前面一篇博文《Analysis of a Euler–Bernoulli beam with Abaqus [Abaqus欧拉-伯努利梁分析]》复习了Abaqus中利用欧拉梁单元B23和B33单元进行悬臂梁的模拟，本文接着看看在 ANSYS APDL 中如何利用欧拉梁单元进行同样的分析。
复习有限元知识，利用 Abaqus 进行欧拉伯努利梁单元的分析。欧拉伯努利梁理论（Euler–Bernoulli beam）又称为工程梁理论（Engineering beam theory）或者经典梁理论（Classical beam theory）。欧拉梁不考虑剪切变形，与铁木辛柯梁（Timoshenko beam）相对。Abaqus中的B23和B33单元为欧拉梁单元。
Plate With Hole Stress Analysis ，带孔平板应力分析。采用Abaqus进行带孔平板应力的平面应力应变分析，单元采用线性三角形单元。
SDOF是一个基于微软的windows窗口程序，用于单自由度结构的动力非线性分析。结构可是弹性也可以是弹塑性。动力荷载可以是施加在结构基座的地震加速度，也可以是施加在结构顶部的动力荷载。程序使用逐步积分法求解增量非线性运动方程。SDOF is a Microsoft Windows based application for the dynamic analysis of single degree of freedom structural systems. The structure may be modeled as elastic, elastic-plastic. The dynamic loading may be input as an earthquake accelerogram acting at the base of the structure, or as a dynamic force applied at the roof of the structure. The program uses a step-by-step method to solve the incrementally nonlinear equations of motion.
[App]OpenSees Material Test.A small program to test the uniaxial materials in OpenSees.OpenSees Material Test将OpenSees ( Open System for Earthquake Engineering Simulation )中常用的单轴本构关系（钢及混凝土本构）提取出来，通过自行设计的界面进行测试，为今后更加深入的研究奠定基础。
Concrete06是基于Thorenfeldt曲线建立的考虑混凝土抗拉强度、非线性受拉硬化及受压性能的单轴本构。
ConcreteD是同济大学李杰老师团队根据中国规范编制的混凝土单轴损伤本构。（ConcreteD is a concrete material based on the Chinese design code.）以下测试一下材料的滞回性能。
Concrete04受压部分的包络线采用Popovics (1973) 提出的单调荷载下的应力—应变关系，并根据Karsan-Jirsa加卸载准则确定其加卸载刚度（线性）；受拉部分的包络线由线性上升段和指数下降段组成，其加卸载与再加载刚度取其与原点的割线刚度。(Concrete is a uniaxial Popovics concrete material object with degraded linear unloading/reloading stiffness according to the work of Karsan-Jirsa and tensile strength with exponential decay.)
OpenSees Concrete02 Material Test.Concrete02与Concrete01相比，考虑了混凝土的受拉力学性能（线性）。在受压方面，与Concrete01相同的是，考虑了混凝土随着残余应变的增大，加、卸载的刚度发生退化；不同的是，Concrete02在同一卸载过程，卸载的刚度也在发生退化。
OpenSees Concrete02 Material Test.Concrete01是OpenSees中最简单的单轴混凝土材料，它基于Kent-Scott-Park单轴混凝土本构模型，根据Karsan-Jirsa加卸载准则确定其加卸载刚度（线性），该材料不考虑混凝土受拉强度。
[01] Ground Motion Selection (选波) 服务
[02] 著:《PERFORM-3D原理与实例》
[03] 著:《有限单元法-编程与软件应用》
[04] 著:《结构地震反应分析-编程与软件应用》
[05] 著:《有限单元法 Python编程》（New!!!）
[06] Software Notes [软件笔记汇总]
[07] 土木工程试验数据处理软件汇总（New!!!）
[08] 自编程序 [Software Box]（New!!!）
[09] 手绘大样 [Detail Drawing]（New!!!）
