XTRACT使用说明整理 - 图文

一、XTRACT3.0.8使用方法介绍及与SAP2000计算结果比较

-------摘自ZengMing博文 题目简介：

钢筋混凝土柱：500mmX500mm

纵向钢筋：8D20mm 钢筋等级HRB400，fyk=400Mpa，fstk=540Mpa 横向钢筋：D8@150mm 钢筋等级HPB300，fyk=300Mpa 混凝土等级C30，对应圆柱体抗压强度标准值为30x0.85=25.5Mpa （本例参数选取仅供参考）。 步骤：

1， 选择截面形式和配置箍筋

2， 选择截面尺寸，配置纵向钢筋：

3, 定义材料本构：

非约束混凝土材料：

约束混凝土

纵向钢筋：

4， 定义纤维尺寸，生成分析截面

5，定义加载工况 计算弯矩曲率曲线工况

计算轴力-弯矩相关曲线工况

定义弯矩2-弯矩3相关曲线工况

,

6，运行分析，查看分析结果

点击

弯矩-曲率曲线

，运行所有的分析，分析结果在界面自动出现。

轴力-弯矩相关性曲线

弯矩2-弯矩3相关性曲线

7， 提取分析结果 点击

，然后选择section1，然后选择M-C工况，选择Section Output。

同理可以绘制出轴力-弯矩相关曲线，在此不再赘述。 在SAP2000截面求解器中编辑此截面，并与之对比。 1， 截面信息

由上图可知，两种软件在弹性阶段基本重合，在塑性阶段，Xtract计算的弯矩要比SAP2000计算的要大。

二、关于其中强度值选取的讨论

1， 详细见混规P286页。立方体抗压强度为C30为例，立方体抗压强度标准值为30MPa，考虑实验的因素，试件混凝土强度为30x0.88=26.4Mpa，转换为棱柱体抗压强度，再折减0.76，即26.4x0.76=20.064Mpa，即表4.1.3-1所示混凝土轴心抗压强度20.1Mpa。

2， Xtract根据ACI规范或软件设计者本意（陆新征老师建议），取圆柱体抗压强度，圆柱体抗压强度为0.79x26.4Mpa=20.856Mpa，这与棱柱体抗压强度20.1Mpa比较接近的，即轴心混凝土轴心抗压强度。

3， 之前我写在XTRACT操作介绍的取值是30x0.85=25.5是错误的，若误导了大家，在此给予致歉，特在此纠正，同时也欢迎更多朋友多多交流。

三、Xtract截面分析小软件应用

这是第一篇博文，本着做好一个结构人的使命，我想写一下xtract这个软件，刚刚完成的地震工程学的作业全靠它了。xtract软件是美国Imbsen公司销售的，用来进行混凝土构件截面Momen-phi分析的小程序，可以很快速的对混凝土截面画出M-phi曲线和N-M相关曲线，是科研和设计非常实用的软件。

和任何人性化的软件一样，xtract支持命令流操作，以梁截面beam.xbj为例：

图1：beam.xbj的截面显示

图2.荷载定义，轴力，Mx，My主要这三项

注意：一般杆件模型的塑性铰定义的时候，梁是M3铰，柱端是PMM铰，具体见《sap2000中文版使用指南》多少页我暂时忘记了，下次补上。

图3.钢筋材性定义，这里是HPB400

图4.C40混凝土本构定义

图5：运行

图6. 右侧输出菜单

图7.输出菜单详解

图8，可以到处数据到excel比较，拟合

Takeda滞回模型考虑钢筋混凝土开裂的影响，采用三线型骨架曲线，并对卸载刚度作了修改，还进一步规定了内滞回规则，见图1。卸载刚度按下式确定：

公式中，Fc、Fy分别对应开裂和屈服时的荷载；dc、dy分别表示对应开裂和屈服时的位移；a是卸载刚度系数。内滞回再加载指向前一外滞回的最大点。当忽略开裂影响而采用双线型骨架线时，除内滞回环规则考虑更多一些外，Takeda滞回模型与Clough滞回模型基本相同。

图9.图1：Takeda

滞回模型

应用sap2000软件。

对于梁截面，定义M3（弯矩—转角）塑性铰来拟合构件的非线性行为，参考FEMA—365规程，通过定义IO，LS，CP三个点来表征塑性铰的能力水平，如图7所示。对于弯曲控制混凝土梁，三个控制点处转角定义为IO：0.003，LS：0.012，CP：0.015。屈服弯矩：214.3kN·m（见三折线模型屈服点）。

柱子的xtract是类似的，不同的是输出的是PMM曲线

区别是在loading里面选择PM interaction

图10 sap里面定义 Column“弯矩—轴力”屈服曲线（PMM曲线）

对于柱截面，定义PMM（轴力—弯矩耦合铰）来拟合构件的非线性行为，将xtract计算结果输入程序中形成PMM屈服面，如图8所示。在任一轴力P作用下，截面“弯矩—转角”关系如上M3铰所述，屈服弯矩（SF）根据PMM屈服面中相应轴力P对应的屈服弯矩给定。

附注：箱型截面：

命令流放在最后（复制到txt里面，另存beam。xbj文件，拖入到xtract图标）： # Project file generated by XTRACT # Created by: 红亮

# WARNING: When this file is read into XTRACT, data consistency checks are NOT performed. If inappropriate

# input data is read into the software, unexpected results may ensue. Before modifying this file, it is advised to

# save a back up copy. The order of the file in not important, nor is the spacing. The file must contain Global

# data as described below. Note that if this file is saved outside XTRACT, the associated output file will be

# automatically deleted when the file is opened.

# Define the global parameters for the file separated by Begin_Global and End_Global

# Version, Units and Name are required.

Begin_Global NAME = beam VER = 3.03 UNITS = N-mm HAS_ANALYZED = True

# Optional parameters Author = 红亮 Company = 大学

Job_Name = 截面M-φ曲线分析 Job_Number = beam

Time_Stamp = 2012/7/1 15:33:16 End_Global

#---------------------------------------

# Begin material definition with Begin_Material and end with End_Material Begin_Material NAME = Steel1

TYPE = Strain Hardening Steel Fy = 360.0 Fu = 360.0 esh = .002 esu = .09 Es = 200.0E+3 End_Material

#---------------------------------------

Begin_Material NAME = C40

TYPE = Confined Concrete Fc = 26.80 ey = .0015 ecu = .0033 Fl = 26.80 Ec = 32.50E+3

# Parameters for the confinement calculators are optional compStrength = 20.00 End_Material

#---------------------------------------

# Begin Section Definitions. Between the Begin and End Section commands, the section shapes and

# loadings are defined. If this is copied to a stand alone (.sec) file, then the section

# materials also need to be defined. # Begin section definition. Begin_Section Begin_Builder NAME = Section1

# Builder properties - boundary window - if left out, the default is used. Boundary_Bottom = -100.0 Boundary_Left = -100.0 Boundary_Right = 700.0 Boundary_Top = 700.0 Min_Triangle_Area = 30.00 Max_Number_of_Fibers = 1000

# Current drawing window properties - if left out, the default is used. Window_Left = 479.7 Window_Bottom = 50.00 Window_Height = 600.0 End_Builder

#---------------------------------------

# Section comments or design log - optional Begin_UserComments User Comments End_UserComments

#---------------------------------------

# Shapes and meshes - for shapes within shapes, list outermost shape first. Shape boundaries may not cross.

# Points are listed in X Y coordinates separated by a comma preceded by the mode of drawing.

# The last point in the sequence of any shape must be the same as the first point to close the shape properly.

# Repeat shape Start_Shape - End_Shape command group as needed. Before editing the shape definitions, make sure

# the data results in reasonable shapes (ie No lines cross, if a shape is embedded in another shape -

# confined within unconfined - the outer shape must be defined first). If the mesh size is defined too

# small, an error will be thrown. To allow for smaller mesh sizes, modify the Max_Number_of_Fibers

# parameter in the section definition.

# Section Shapes Begin_Shape

MATERIAL = C40 MESH = 20.00 COVER = 30.00 MATERIAL_CORE = C40 Begin_Line 0, 0 250.0, 0 250.0, 500.0 0, 500.0 0, 0 End_Line End_Shape

#---------------------------------------

# Reinforcing bars. Data is given comma separated in the form X, Y, Area, Prestress, Material. Begin_Rebar

50.80, 457.2, 314.2, 0, Steel1 127.0, 457.2, 314.2, 0, Steel1 203.2, 457.2, 314.2, 0, Steel1 50.80, 50.80, 314.2, 0, Steel1 127.0, 50.80, 314.2, 0, Steel1 203.2, 50.80, 314.2, 0, Steel1 203.2, 254.0, 314.2, 0, Steel1 127.0, 254.0, 314.2, 0, Steel1 50.80, 254.0, 314.2, 0, Steel1 End_Rebar

#---------------------------------------

# Define the loading data, choose Moment Curvature, Capacity Orbit, or PM Interaction for loading type.

# Required data not defined here is taken from default values. Begin_Loading

NAME = mfi

TYPE = Moment Curvature

# Incrementing load parameters - Positive increments in a positive direction. IncMxx = 113.0

Use_Best_Fit = True

# Include Plastic Hinge length. Calc_Moment_Rot = False

# Analysis Parameters. Method = BiSection N_Steps_Before_Yield = 10 N_Steps_After_Yield = 20 Multiple_On_First_Yield = 2 BS_Tol = 4448 BS_Max_Itter = 40

Begin_LoadUserComments User Comments End_LoadUserComments End_Loading

#---------------------------------------

End_Section

#---------------------------------------

命令流放在最后（复制到txt里面，另存column。xbj文件，拖入到xtract图标）

# Project file generated by XTRACT # Created by: 红亮

# WARNING: When this file is read into XTRACT, data consistency checks are NOT performed. If inappropriate

# input data is read into the software, unexpected results may ensue. Before modifying this file, it is advised to

# save a back up copy. The order of the file in not important, nor is the spacing. The file must contain Global

# data as described below. Note that if this file is saved outside XTRACT, the associated output file will be

# automatically deleted when the file is opened.

# Define the global parameters for the file separated by Begin_Global and End_Global

# Version, Units and Name are required. Begin_Global NAME = beam VER = 3.03 UNITS = N-mm HAS_ANALYZED = True

# Optional parameters Author = 红亮 Company = 大学

Job_Name = 截面M-φ曲线分析 Job_Number = beam

Time_Stamp = 2012/7/1 15:33:16 End_Global

#---------------------------------------

# Begin material definition with Begin_Material and end with End_Material Begin_Material NAME = Steel1

TYPE = Strain Hardening Steel Fy = 360.0 Fu = 360.0 esh = .002 esu = .09 Es = 200.0E+3 End_Material

#---------------------------------------

Begin_Material NAME = C40

TYPE = Confined Concrete Fc = 26.80 ey = .0015 ecu = .0033 Fl = 26.80 Ec = 32.50E+3

# Parameters for the confinement calculators are optional

compStrength = 20.00 End_Material

#---------------------------------------

# Begin Section Definitions. Between the Begin and End Section commands, the section shapes and

# loadings are defined. If this is copied to a stand alone (.sec) file, then the section # materials also need to be defined. # Begin section definition. Begin_Section Begin_Builder NAME = Section1

# Builder properties - boundary window - if left out, the default is used. Boundary_Bottom = -100.0 Boundary_Left = -100.0 Boundary_Right = 700.0 Boundary_Top = 700.0 Min_Triangle_Area = 30.00 Max_Number_of_Fibers = 1000

# Current drawing window properties - if left out, the default is used. Window_Left = 479.7 Window_Bottom = 50.00 Window_Height = 600.0 End_Builder

#---------------------------------------

# Section comments or design log - optional Begin_UserComments User Comments End_UserComments

#---------------------------------------

# Shapes and meshes - for shapes within shapes, list outermost shape first. Shape boundaries may not cross.

# Points are listed in X Y coordinates separated by a comma preceded by the mode of drawing.

# The last point in the sequence of any shape must be the same as the first point to close the shape properly.

# Repeat shape Start_Shape - End_Shape command group as needed. Before editing the shape definitions, make sure

# the data results in reasonable shapes (ie No lines cross, if a shape is embedded in another shape -

# confined within unconfined - the outer shape must be defined first). If the mesh size is defined too

# small, an error will be thrown. To allow for smaller mesh sizes, modify the Max_Number_of_Fibers

# parameter in the section definition.

# Section Shapes Begin_Shape MATERIAL = C40 MESH = 20.00 COVER = 30.00 MATERIAL_CORE = C40 Begin_Line 0, 0 500.0, 0 500.0, 500.0 0, 500.0

0, 0 End_Line End_Shape

#---------------------------------------

# Reinforcing bars. Data is given comma separated in the form X, Y, Area, Prestress, Material. Begin_Rebar

50.80, 457.2, 314.2, 0, Steel1 50.80, 50.80, 314.2, 0, Steel1 50.80, 254.0, 314.2, 0, Steel1 457.2, 457.2, 314.2, 0, Steel1 457.2, 254.0, 314.2, 0, Steel1 457.2, 50.80, 314.2, 0, Steel1 254.0, 457.2, 314.2, 0, Steel1 254.0, 50.80, 314.2, 0, Steel1 End_Rebar

#---------------------------------------

# Define the loading data, choose Moment Curvature, Capacity Orbit, or PM Interaction

for loading type.

# Required data not defined here is taken from default values. Begin_Loading

NAME = mfi

TYPE = Moment Curvature

# Incrementing load parameters - Positive increments in a positive direction. IncAxial = -4448

Use_Best_Fit = True

# Include Plastic Hinge length. Calc_Moment_Rot = False

# Analysis Parameters. Method = BiSection N_Steps_Before_Yield = 10

N_Steps_After_Yield = 20 Multiple_On_First_Yield = 2 BS_Tol = 4448 BS_Max_Itter = 40

Begin_LoadUserComments User Comments End_LoadUserComments End_Loading

#---------------------------------------

Begin_Loading

NAME = pm

TYPE = PM Interaction

N_PM_Points = 20

Generate_Code_PM_Diagram = True Include_PM_Curve_Fit = True Angle_of_Loading = 0

Axial0 = 0 Axial1 = 0 Axial_Cap = 0 AxialR0 = 0 AxialR1 = 0 Moment0 = 0 Moment1 = 0 Moment2 = 0

# Limit Strains for PM Loading.

# Negative strains are compression. The default PM minimum and maximum strain limits # are used if data is not given for materials in the section.

# Data is given comma separated in the form Material, Minimum Stain, Maximum Strain between the

# Begin_LimitStrains and End_LimitStrains command. Begin_LimitStrains Steel1, -.002, .002 C40, -.002, 1 End_LimitStrains

Begin_LoadUserComments User Comments End_LoadUserComments End_Loading

#---------------------------------------

End_Section

#---------------------------------------

四、

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