ABAQUS 常见问题
ABAQUS常见问题总结

ABAQUS注意事项1、建模前需要考虑的因素1)根据结构和荷载情况的特点,按照轴对称问题来建模。
2)对于大位移问题,应在step功能模块中把参数Nlgeom(几何非线性)设为ON。
3)根据问题的特点,选用合适的单元类型。
2、新建Part时,Approximate size (sketch) 的大小?Approximate size数值的大小,应根据模型的最大尺寸来确定:稍大于最大尺寸的2倍。
3、ABAQUS中平面应力、应变问题的截面属性为什么是实体而不是壳?那个壳设置是专门针对板壳单元的,用于板壳力学分析。
平面应力应变分析当然该选实体,因为是我们把三维实体分析简化成平面分析的。
3、ABAQUS有限元分析实例详解——石亦平注意事项1)P176页在单向压缩试验过程模拟时,试样冒设为解析刚体,建模时用一直线表示,而不是用一矩形表示,如果用矩形表示,其接触部位的尖角会造成错误的分析结果。
同时,代表试样冒的直线也必须绘制的足够长,因为压缩的过程中,试样的截面尺寸会不断增大,如果试样尺寸超出试样冒的尺寸,会造成接触分析的收敛问题。
4、选择主动面和从属面的几个原则1)Analytical rigid surfaces and rigid-element-based surfaces must always be the mastersurface.2)A node-based surface can act only as a slave surface and always uses node-to-surfacecontact.3)Slave surfaces must always be attached to deformable bodies or deformable bodiesdefined as rigid.4)Both surfaces in a contact pair cannot be rigid surfaces with the exception of deformablesurfaces defined as rigid5)当存在一个较小的面和一个较大的面时,一般将较小的面定义为从属面。
使用ABAQUS过程中遇到的问题及相应解决方法

使用ABAQUS过程中遇到的问题及相应的解决方法
总结下在使用ABAQUS过程中遇到的问题,以及相应的解决办法。
出现问题的原因可能有很多,解决方法也不一定是最好,记录下来,只是给他家提供一个思路。
问题一
描述:节点缺失自由度。
xx个nodes are missing degree of freedoms.
原因:做一个框架结点,边界条件全部用点耦合到面上,再约束点。
两个面分别约束到两个不同的点上,这两个面是不能有交线的,如果有交线,会相互干涉。
解决:干掉一个耦合,换别的约束。
问题二
描述:The executable pre.exe aborted with system error code 1073741819.
原因:遇到这个问题的时候,我的cae是在自己机器里先运行过的,inp已经过了,没问题,可以开始计算,但是放到服务器里去跑就不行了。
重启过,没用。
解决:把cae名称里的中文干掉,然后换了个文件夹执行,就好了。
问题三
描述:Unable to delete File(s). 。
msg
原因:之前的msg没有干掉,然后他就没法算了,看上去是这样,深究的话可能跟权限有关,别的我也不知道了。
解决:这个问题比较简单,手动删除msg,重新Submit即可。
问题四
描述:后台输出CF或者RF为零
原因:模型做完,后处理基本都得看荷载-位移曲线,但是有的时候RF或CF会为零。
解决:如果施加的是力,就看CF,如果施加的是位移,就看RF。
Abaqus遇到的问题小结

Abaqus遇到的问题小结1.Abaqus量纲系统(SI):m、N、Kg、s、Pa、J、Kg/m3。
2.有限元单元类型(Element Type):实体单元、壳单元、杆件单元(梁Beam、桁架Truss)怎样将部件的不同部分设定为不同的子集?tools >partition cell/plane(如果是要分层使用,则进行分割,分别赋予不同的属性;或者对其中的单元进行设置Set;如果要在运算中替换则需要在关键词里添加语句定义)4.建模的过程中输入的尺寸被自动降低精度(四舍五入),请问如何设置尺寸精度(小数点位数)?在 sketch option里打开sketch模块(左下角最下面)打开sketchoption 对话框,其中decimal places 表示小数点位数,默认为2,最高能调到6 。
中出现,Dependent partinstances connot be edited ,怎么办?mesh on part , mesh on instance一个非独立实体只是原始部件的一个指针,可以对原始部件划分网格,但是不能对一个非独立实体划分网格,即mesh on part。
方法:左边模型树里面,Assembly->instances里面的子选项右击,点Make independent;或者点击model旁边的Part,对part进行网格划分。
6.材料属性中拉伸强度和压缩强度怎么定义?计算结果有每个计算节点的应力,计算中用不到强度值(弹性力学三组基本方程不涉及强度,求解过程用不到)。
(强度值是用来校核的:断裂,屈服或超过线性变形)7.如何选择创建独立实体还是非独立实体?如果集合中包含许多具有相同性质的部件,则创建非独立实体(Dependent)。
反之,如果集合中包含许多不同性质的部件,则创建独立实体(Independent)要有优势些。
8.地基土的分层问题?方法1:定义为一个part,然后partition分层赋材料属性,不需要设置接触。
ABAQUS常见问题汇总

HM——ABA接口问题简洁一些,引用小宝斑竹在接口问题中的体会:“关于hm-abaqus的接口补充说明经常用HM-abqus的人或者刚开始使用的人,对于软件的接口一般存在以下问题:1、INP文件导入abaqus出错。
2、在abaqus里选择加载面,设置材料属性不方便。
(也可以理解为没有几何元素的模型在网格上选取东东比较困难)除了以上的两种,暂时我还没发现其他的问题。
对于1,只要前处理没有除网格外的载荷信息,并且所有关键字名称都没有数字,那么恭喜你,它一定不会出错。
(当然,有些人说abaqus/cae有很多关键字不支持,但是hm支持。
我的建议是:有那功夫,或许INP文件都改完了)对于2,首先声明,所有在hm里建立的SET,都会出现在abaqus assembly里的set里,所以在abaqus里加载的时候,都是可以调用的,你所要做的就是正确的建立node set or element set。
很多人知道在abaqus part里也有个set,那个是干什么的呢?目前我就是用来操作材料施加的。
很多时候模型是各种复杂材料的混合,如果在abaqus里直接赋予,选取模型区域的手段有限(单个点,点到手抽筋;by angle,很多地方选不上,选到眼花;by set,在abaqus里建立part set的难度不下于手动点),我的建议:在hm里赋予一个空材料属性给相关的区域(hm 里有几何元素,选起来简直就是小CASE),到了abaqus里,软件会自动为你的每个材料区建立一个新的part set,这时候,空的材料属性要炸要炒随你便。
剩下的问题都不是问题。
”论坛问题汇总1、hypermesh导入abaqus有单元显示、无模型显示。
答:这个问题很常见,不仅在hypermesh_to_abaqus中有人问,在HM与其它软件接口也有人反复问。
首先要肯定的是导入过程没有任何问题。
在此,引用老向版主的一段话来回答“版上不停的有人问为什么HM不能导出几何.看的人都烦了.为什么要导出几何呢?不同的软件,对几何的理解是不一样的, 所以才有这么多的不同的几何格式.如果要导出几何,HM还得去研究你abaqus/ansys/patran内部是如何理解几何的,这是个浩大的工程.你应该知道,对于求解器来说,它只需要知道节点,单元,材料,载荷等信息就能够求解了.要几何干什么呢?几何模型的作用仅仅是为了得到节点,网格.. 一旦有节点,网格有了,几何模型就可以扔掉了.后处理程序本身也是基于有限元模型的,而不是基于几何模型的.你既然打算用HM做前处理,就干脆一点,把所有的东西都在HM里面做好,然后提交给abaqus/nastran计算就行了.HM对abaqus求解器的支持一点不比abaqus/cad本身差,只有及少数特殊的场合,需要手工添加一些语句.”2、从HM中把一个装配件划分好的网格生成inp文件后,导入abaqus中去,为什么是一个零件,怎样才能是一个装配件?答:part, instance是abaqus独有的概念。
《ABAQUS 元分析常见问题解答》常见问题汇总

第1章关于 Abaqus 基本知识的常见问题第一篇基础篇第1章关于 Abaqus 基本知识的常见问题第1章关于 Abaqus 基本知识的常见问题1.1 Abaqus 的基本约定1.1.1 自由度的定义【常见问题1-1】Abaqus 中的自由度是如何定义的?1.1.2 选取各个量的单位【常见问题1-2】在 Abaqus 中建模时,各个量的单位应该如何选取?1.1.3 Abaqus 中的时间【常见问题1-3】怎样理解 Abaqus 中的时间概念?第1章关于 Abaqus 基本知识的常见问题1.1.4 Abaqus 中的重要物理常数【常见问题1-4】Abaqus 中有哪些常用的物理常数?1.1.5 Abaqus 中的坐标系【常见问题1-5】如何在 Abaqus 中定义局部坐标系?1.2 Abaqus 中的文件类型及功能【常见问题1-6】Abaqus 建模和分析过程中会生成多种类型的文件,它们各自有什么作用? 【常见问题1-7】提交分析后,应该查看 Abaqus 所生成的哪些文件?1.3 Abaqus 的帮助文档1.3.1 在帮助文档中查找信息【常见问题1-8】如何打开 Abaqus 帮助文档?第1章关于 Abaqus 基本知识的常见问题【常见问题1-9】Abaqus 帮助文档的内容非常丰富,如何在其中快速准确地找到所需要的信息?1.3.2 在 Abaqus/CAE 中使用帮助【常见问题1-10】Abaqus/CAE 的操作界面上有哪些实时帮助功能?【常见问题1-11】Abaqus/CAE 的 Help 菜单提供了哪些帮助功能?1.4 更改工作路径【常见问题1-12】Abaqus 读写各种文件的默认工作路径是什么?如何修改此工作路径?1.5 Abaqus 的常用 DOS 命令【常见问题1-13】Abaqus 有哪些常用的 DOS 命令?第1章关于 Abaqus 基本知识的常见问题1.6 设置 Abaqus 的环境文件1.6.1 磁盘空间不足【常见问题1-14】提交分析作业时出现如下错误信息,应该如何解决?***ERROR: UNABLE TO COMPLETE FILE WRITE. CHECK THAT SUFFICIENT DISKSPACE IS AVAILABLE. FILE IN USE AT F AILURE IS shell3.stt.(磁盘空间不足)或者***ERROR:SEQUENTIAL I/O ERROR ON UNIT 23, OUT OF DISK SPACE OR DISK QUOTAEXCEEDED.(磁盘空间不足)1.6.2 设置内存参数【常见问题1-15】提交分析作业时出现如下错误信息,应该如何解决?***ERROR: THE SETTING FOR PRE_MEMORY REQUIRES THAT 3 GIGABYTES OR MOREBE ALLOCATED BUT THE HARDWARE IN USE SUPPORTS ALLOCATION OF AT MOST 3GIGABYTES OF MEMORY. EITHER PRE_MEMORY MUST BE DECREASED OR THE JOBMUST BE RUN ON HARDWARE THAT SUPPORTS 64-BIT ADDRESSING.(所设置的pre_memory 参数值超过3G,超出了计算机硬件所能分配的内存上限)或者***ERROR: THE REQUESTED MEMORY CANNOT BE ALLOCATED. PLEASE CHECK THESETTING FOR PRE_MEMORY. THIS ERROR IS CAUSED BY PRE_MEMORY BEINGGREATER THAN THE MEMORY AVAILABLE TO THIS PROCESS. POSSIBLE CAUSES AREINSUFFICIENT MEMORY ON THE MACHINE, OTHER PROCESSES COMPETING FORMEMORY, OR A LIMIT ON THE AMOUNT OF MEMORY A PROCESS CAN ALLOCATE.(所设置的 pre_memory 参数值超出了计算机的可用内存大小)第1章关于 Abaqus 基本知识的常见问题或者***ERROR: INSUFFICIENT MEMORY. PRE_MEMORY IS CURRENTLY SET TO 10.00MBYTES. IT IS NOT POSSIBLE TO ESTIMATE THE TOTAL AMOUNT OF MEMORY THATWILL BE REQUIRED. PLEASE INCREASE THE VALUE OF PRE_MEMORY.(请增大pre_memory 参数值)或者***ERROR: THE VALUE OF 256 MB THAT HAS BEEN SPECIFIED FORSTANDARD_MEMORY IS TOO SMALL TO RUN THE ANALYSIS AND MUST BEINCREASED. THE MINIMUM POSSIBLE VALUE FOR STANDARD_MEMORY IS 560 MB.(默认的standard_memory 参数值为256 M,而运行分析所需要的standard_memory 参数值至少为560 M)1.7 影响分析时间的因素【常见问题1-16】使用 Abaqus 软件进行有限元分析时,如何缩短计算时间?【常见问题1-17】提交分析作业后,在 Windows 任务管理器中看到分析作业正在运行,但 CPU 的使用率很低,好像没有在执行任何工作任务,而硬盘的使用率却很高,这是什么原因?1.8 Abaqus 6.7新增功能【常见问题1-18】Abaqus 6.7 版本新增了哪些主要功能?第1章关于 Abaqus 基本知识的常见问题1.9 Abaqus 和其它有限元软件的比较【常见问题1-19】Abaqus 与其他有限元软件有何异同?第2章关于 Abaqus/CAE 操作界面的常见问题第2章关于Abaqus/CAE 操作界面的常见问题2.1 用鼠标选取对象【常见问题2-1】在 Abaqus/CAE 中进行操作时,如何更方便快捷地用鼠标选取所希望选择的对象(如顶点、线、面等)?2.2 Tools 菜单下的常用工具2.2.1 参考点【常见问题2-2】在哪些情况下需要使用参考点?2.2.2 面【常见问题2-3】面(surface)有哪些类型?在哪些情况下应该定义面?第2章关于 Abaqus/CAE 操作界面的常见问题2.2.3 集合【常见问题2-4】集合(set)有哪些种类?在哪些情况下应该定义集合?2.2.4 基准【常见问题2-5】基准(datum)的主要用途是什么?使用过程中需要注意哪些问题?2.2.5 定制界面【常见问题2-6】如何定制 Abaqus/CAE 的操作界面?【常见问题2-7】6.7版本的 Abaqus/CAE 操作界面上没有了以前版本中的视图工具条(见图2-6),操作很不方便,能否恢复此工具条?图2-6 Abaqus/CAE 6.5版本中的视图工具条第3章Part 功能模块中的常见问题第3章Part 功能模块中的常见问题3.1 创建、导入和修补部件3.1.1 创建部件【常见问题3-1】在 Abaqus/CAE 中创建部件有哪些方法?其各自的适用范围和优缺点怎样? 3.1.2 导入和导出几何模型【常见问题3-2】在 Abaqus/CAE 中导入或导出几何模型时,有哪些可供选择的格式?【常见问题3-3】将 STEP 格式的三维 CAD 模型文件(*.stp)导入到 Abaqus/CAE 中时,在窗口底部的信息区中看到如下提示信息:A total of 236 parts have been created.(创建了236个部件)此信息表明 CAD 模型已经被成功导入,但是在 Abaqus/CAE 的视图区中却只显示出一条白线,看不到导入的几何部件,这是什么原因?第3章Part 功能模块中的常见问题3.1.3 修补几何部件【常见问题3-4】Abaqus/CAE 提供了多种几何修补工具,使用时应注意哪些问题?【常见问题3-5】将一个三维 CAD 模型导入 Abaqus/CAE 来生成几何部件,在为其划分网格时,出现如图3-2所示的错误信息,应如何解决?图3-2 错误信息:invalid geometry(几何部件无效),无法划分网格3.2 特征之间的相互关系【常见问题3-6】在 Part 功能模块中经常用到三个基本概念:基本特征(base feature)、父特征(parent feature)和子特征(children feature),它们之间的关系是怎样的?第3章Part 功能模块中的常见问题3.3 刚体和显示体3.3.1 刚体部件的定义【常见问题3-7】什么是刚体部件(rigid part)?它有何优点?在 Part 功能模块中可以创建哪些类型的刚体部件?3.3.2 刚体部件、刚体约束和显示体约束【常见问题3-8】刚体部件(rigid part)、刚体约束(rigid body constraint)和显示体约束(display body constraint)都可以用来定义刚体,它们之间有何区别与联系?3.4 建模实例【常见问题3-9】一个边长 100 mm 的立方体,在其中心位置挖掉半径为20 mm 的球,应如何建模? 『实现方法1』『实现方法2』第4章Property 功能模块中的常见问题第4章 Property 功能模块中的常见问题4.1 超弹性材料【常见问题4-1】如何在 Abaqus/CAE 中定义橡胶的超弹性(hyperelasticity)材料数据?4.2 梁截面形状、截面属性和梁横截面方位4.2.1 梁截面形状【常见问题4-2】如何定义梁截面的几何形状和尺寸?【常见问题4-3】如何在 Abaqus/CAE 中显示梁截面形状?4.2.2 截面属性【常见问题4-4】截面属性(section)和梁截面形状(profile)有何区别?第4章Property 功能模块中的常见问题【常见问题4-5】提交分析作业时,为何在 DAT 文件中出现错误提示信息“elements have missing property definitions(没有定义材料特性)”?『实 例』出错的 INP 文件如下:*NODE1, 0.0 , 0.0 , 0.02, 20.0 , 0.0 , 0.0*ELEMENT, TYPE=T3D2, ELSET=link1, 1, 2*BEAM SECTION, ELSET=link, MATERIAL= steel, SECTION=CIRC15.0,提交分析作业时,在 DAT 文件中出现下列错误信息:***ERROR:.80 elements have missing property definitions The elements have been identified inelement set ErrElemMissingSection.4.2.3 梁横截面方位【常见问题4-6】梁横截面方位(beam orientation)是如何定义的?它有什么作用?【常见问题4-7】如何在 Abaqus 中定义梁横截面方位?【常见问题4-8】使用梁单元分析问题时,为何出现下列错误信息:***ERROR: ELEMENT 16 IS CLOSE TO PARALLEL WITH ITS BEAM SECTION AXIS.第4章Property 功能模块中的常见问题DIRECTION COSINES OF ELEMENT AXIS 2.93224E-04 -8.20047E-05 1.0000. DIRECTIONCOSINES OF FIRST SECTION AXIS 0.0000 0.0000 1.0000。
用Abaqus所遇到问题汇总

用Abaqus 所遇到问题汇总(持续更新)2011-02-17 02:45:26 转载▼ 标签:分类:好好学习abaqus杂谈问题1:当Verification 所有都pass 的时候,仍然提示Problem during compilation - ifort.exe not found in PATH解决办法:找到ABAQUS 安装目录下的Commands 文件夹例如D:SIMULIAAbaqusCommands下的abq6101.bat,右键,编辑此文件,插入下面这行使之成为第一行:8 P O2 b W R4 y6 U5ucallquotX:yourdirIntelCompilerFortranversionIA32Binifortvar s.batquot,例如我的是:- k q V/ : EcallquotC:ProgramFilesIntelCompiler11.1070binia32ifortvars_ia32. batquot f9 G9 R C0 Lamp quot d/ Y d问题2:当使用UMAT 子程序是出现以下错误Error in job Job-line44: 630 elements have been defined with zero hourglass stiffness. You may use hourglass stiffness or change the elementtype. The elements have been identified in element setErrElemZeroHourGlassStiffness.解决办法:由于设置了减缩积分,所以出现沙漏现象,将其改成全积分或imcompatible 可解决,详细解析在《基于ABAQUS 的有限元分析和应用》的第510页。
问题3:提交作业后模型出现问题,standard.exe 停止工作,只生成dat 文件而没有找到msg 文件解决办法:黄色图标的文件即msg 文件,但文件类型显示为outlook,用记事本打开即可。
Abaqus常见问题解答

更新时间:2014-8-12
ABAQUS被广泛地认为是功能最强的有限元软件,可以分析复 杂的固体力学结构力学系统,并能驾驭高度非线性的模拟问题。 ABA级的分析和研究。
作为通用的模拟工具, ABAQUS 除了能解决大量结构(应力 / 位移)问题,还可以模拟其他工程领域的许多问题,例如热传 导、质量扩散、热电耦合分析、振动与声学分析、岩土力学分析 (流体渗透 / 应力耦合分析)及压电介质分析。ABAQUS独一无二 的系统级分析特点和模拟复杂系统的可靠性使得ABAQUS被各国的 工业和研究中所广泛的采用。
A:可能有很多初学者对分析步,增量步和迭代步的定义不是很明确,这 里正好看到一本书上描述的很清楚,这里和各位分享一下。 ·模拟计算
的加载过程包含单个或多个步骤,所以要定义分析步。它一般包含分析
过程选择,载荷选择,和输出要求选择。而且每个分析步都可以 采用不同的载荷、边界条件、分析过程和输出要求。例如: 步骤 一:将板材夹于刚性夹具上。步骤二:加载使板材变形。 步骤三
问答:
1.怎么在abaqus中设置集中质量?
A:1.cae中建立一个点刚体,然后在section中选择point的属性,
给出惯性特征就行了。
2.在keyword中添加: *element,type=mass,elset=pointmass 1(单元号),1(point) *mass,elset=pointmass 2.2(质量大 小) 这样就建立一个质量为2.2,在node 1上建立的。
*END STEP
**---------------------------------------------------*STEP, NAME=staticstepupper, INC=999
用Abaqus所遇到问题汇总

用Abaqus 所遇到问题汇总(持续更新)2011-02-17 02:45:26 转载▼ 标签:分类:好好学习abaqus杂谈问题1:当Verification 所有都pass 的时候,仍然提示Problem during compilation - ifort.exe not found in PATH解决办法:找到ABAQUS 安装目录下的Commands 文件夹例如D:SIMULIAAbaqusCommands下的abq6101.bat,右键,编辑此文件,插入下面这行使之成为第一行:8 P O2 b W R4 y6 U5ucallquotX:yourdirIntelCompilerFortranversionIA32Binifortvar s.batquot,例如我的是:- k q V/ : EcallquotC:ProgramFilesIntelCompiler11.1070binia32ifortvars_ia32. batquot f9 G9 R C0 Lamp quot d/ Y d问题2:当使用UMAT 子程序是出现以下错误Error in job Job-line44: 630 elements have been defined with zero hourglass stiffness. You may use hourglass stiffness or change the elementtype. The elements have been identified in element setErrElemZeroHourGlassStiffness.解决办法:由于设置了减缩积分,所以出现沙漏现象,将其改成全积分或imcompatible 可解决,详细解析在《基于ABAQUS 的有限元分析和应用》的第510页。
问题3:提交作业后模型出现问题,standard.exe 停止工作,只生成dat 文件而没有找到msg 文件解决办法:黄色图标的文件即msg 文件,但文件类型显示为outlook,用记事本打开即可。
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The ABAQUS FAQT HE ABAQUS FAQ 01.G ENERAL Q UESTIONS (2)2.J OBS (5)3.E LEMENTS (9)4.ABAQUS-M ESH (13)5.ABAQUS-M ATERIALS (15)6.ABAQUS-B OUNDARY C ONDITIONS (19)7.L OADING (23)8.ABAQUS-P ROCEDURES (33)9.ABAQUS-A NALYSIS (34)10.O UTPUT (40)11.ABAQUS/P OST -G ENERAL (45)12.ABAQUS/P OST -C ONTOURS (50)13.ABAQUS/P OST -M ESH P LOTS (53)14.ABAQUS/P OST -XY P LOTS (56)15.ABAQUS/P OST -V ECTOR P LOTS (59)16.ABAQUS/P OST -P ATH P LOTS (59)17.ABAQUS/P OST -V IEWS (60)18.ABAQUS/P OST -H ARDCOPY (61)19.ABAQUS/P LOT (63)20.P RE PROCESSING USING PATRAN (64)21.P OST PROCESSING USING PATRAN (65)22.P RE PROCESSING USING FEMGV (66)23.P OST PROCESSING USING FEMGV (67)24.ABAQUS-E RRORS (69)1. General QuestionsQ1.1 : How much disk space do I need?Minimum of 10 MBytes to run simple examples if using PATRAN for Pre or Post processing. Probably about 20 MBytes for medium sized problems.The amount of disk space required depends on the numbers of nodes/elements present in the mesh and the output frequency requested for outputting data to the *.fil, *.dat and *.res files. The following ABAQUS files are created in the user's home directory.*.dat, *.fil, *.res, *.msg, *.sta, *.log, *.job, *.023 (deleted at the completion of the ABAQUS job).Q1.2 : What type of analysis can I do?The procedures available in ABAQUS are listed below (in alphabetical order) : ∙BUCKLE∙COUPLED TEMPERATURE-DISPLACEMENT (steady state and transient)∙COUPLED THERMAL-ELECTRICAL (steady state and transient)∙DYNAMIC∙FREQUENCY∙GEOSTATIC∙HEAT TRANSFER (steady state and transient)∙MASS DIFFUSION (steady state and transient)∙MODAL DYNAMIC∙RANDOM RESPONSE∙RESPONSE SPECTRUM∙SOILS, CONSOLIDATION∙SOILS, STEADY STATE∙STATIC∙STEADY STATE DYNAMICS∙VISCOQ1.3 : What output options (hard copy) are there?With ABAQUS 5.7 any size plots (including A3 and A4) can be obtained.If using PATRAN of FEMGV hard copies of any size (includng A4 and A3) can be obtained. Q1.4 : What pre and post-processing programs are available other than ABAQUS/Post?PATRAN and FEMGV are available in the teaching system.Both these programs read the results file *.fil for post processing.If you are post processing using FEMGV and have written results at element Gauss points then you need to write the gauss point co-ordinates as well. Include the following lines in the ABAQUS input file :*EL FILE, POSITION=INTEGRATION POINTSSECOORDOtherwise it will not be possible to use the FEMGV program to post process the element gauss point results ie FEMGV would not know the location of the gauss points.Q1.5 : Is ABAQUS/Pre available?No. ABAQUS/Pre is not available in the teaching system. However PATRAN which provides the same functionality and which has the same look and feel of ABAQUS/Pre is available in the teaching system. Type patran to run the PATRAN program.Q1.6 : Is ABAQUS/Explicit available?ABAQUS/Explicit is only licenced on tw900. You need to rlogin to tw900 to run this version of ABAQUS. ABAQUS/Standard is also available on tw900.Q1.7 : What on-line documentation are available and how do I access it?Type abaqus57 doc in the CUED teaching system to access the full set of the ABAQUS Users' manual (Volumes I, II and III).At present this is the only on-line documentation available except for ABAQUS Release Notes (100 pages) and ABAQUS Site Guide (80 pages).Q1.8 : What units are used in ABAQUS?There is no inherent set of units used in ABAQUS. It is up to the user to decide on a consistent set of units and use that units. Typical sets of units :1 2Length - metres mmForce - Newtons NewtonsTime - second secondMass - Kg tonne (**)Density - Kg/m3 tonne/mm3Stress - N/m2 N/mm2 (= MPa)Young's Modulus - N/m2 N/mm2 (= MPa)** 1 tonne = 1000 kilogramsDecide on the units before you start preparing your data. This is critical. If you start typing in the nodal co-ordinates that means you have already decided on what units to user for the Length parameter. This only leaves the choice for the units of Force.It is not a good idea to choose mm for length, Newton for force and then specify the Young's modulus in KN/m2.2. JobsQ2.1 : How do I run small jobs?Use the following commandabaqus job=job-id interactiveExample : abaqus job=plateQ2.2 : How do I go about running many small jobs?Create a batch file (say aba.run) with one line per analysis as shown below :abaqus job=analysis-a interactiveabaqus job=analysis-b interactiveabaqus job=analysis-c interactiveabaqus job=analysis-d interactiveThen make the file an executable using the following unix command :chmod u+x aba.runThen type aba.run to execute the ABAQUS jobs one at a time while you are logged ON. This is only suitable for small jobs which only take a few minutes to run. These jobs will run one at a time and in sequence.This is preferable to submitting all the jobs at the same time (for example typing the above commands directly at the terminal without the interactive parameter). This will put a strain on the server and its resources and inconvenience the other users as well.For medium to large jobs use the batch command available in the CUED teaching system.Q2.3 : How do I run large jobs using batch?In the CUED teaching system use the batch command. To run the job on tw500 or tw900 servers use :batch -QX -mbao "abaqus job=job-id interactive"To run a job specifically on the tw900 server use :batch -QN -mbao "abaqus job=job-id interactive"Example :batch -QN -mbao "abaqus job=plate interactive"The progress of the submitted job can be monitored using the batchq command. Use the batchrm command to delete any batch jobs you had submitted before these are run, if you change your mind. See the man pages on batchq, batchrm for more details. Example : Type man batchq.Q2.4 : How do I run ABAQUS/Post?Using the following command :abaqus post job=job-idExample : abaqus post job=cantileverQ2.5 : How do I run ABAQUS/Plot?Using the following command :abaqus plot job=job-id device=cps or hgl or x11Use device=x11 to view the plots on the screen. Use one of the other options (cps for colour postscript or hgl for hpgl) to create a hard copy of the plot.Example : abaqus post device=cps job=cantileverQ2.6 : How do I get copies of the ABAQUS examples input data files (*.inp)?The ABAQUS datafiles used in the examples manual can be found in the/export/abaqus/samples/exastd directory. Similarly the datafiles in the verification manual can be found in /export/abaqus/samples/verstd directory. These files will have the extension name inp. All file names are in lowercase. use the cp command to copy the relevant file.Example : cp /export/abaqus/samples/exastd/1010101.inp .This will copy the 1010101.inp file to the current directory.If these directories don't exist then can use the abaqus fetch command.Example : abaqus fetch job=1010101Q2.7 : How do I run a ABAQUS job which uses a user subroutine?Using the following command :abaqus job=job-idAs can be seen this is no different from running a standard abaqus job. The user subroutine itself can be embedded in the abaqus input file. Here it is illustrated with the umat subroutine.<....part of the abaqus input file ....>................*END STEP*USER SUBROUTINESSUBROUTINE UMAT(........)................END........Alternatively the user subroutine can be in a separate file (say my_material.f) and the INPUT parameter is set to that file name.<....part of the abaqus input file ....>................*USER SUBROUTINES, INPUT=my_material.f................Q2.8 : How do I run a user written post processing program which accesses the *.fil file?Using the following command :abaqus make job=job-id user=name-of-fileExample : abaqus make job=cantilever user=disp1This will compile the user program in a file called disp1.f and then create an executable called cantilever.x. Type cantilever.x to run this program.Q2.9 : How do I find out about the different execution procedures that are available with ABAQUS?Type abaqus help and this will list all the abaqus execution procedures. These are listed below :Execution Procedure for ABAQUS/Standard and ABAQUS/Explicitabaqus job=job-name [ analysis | datacheck | continue | help | recover |convert={restart|select|all} |information={environment|local|memory|release|status} ] [ input=input-file ] [ user=source-file ][ oldjob=oldjob-name ] [ fil={append|new} ][ globalmodel=results file-name ] [ double ][ memory=memory-size ] [ buffer=buffer-size ][ interactive | background | queue=queue-name ][ cpus=number-of-cpus ] [scratch=scratch-dir][ subcomplex=subcomplex-name]Note: subcomplex is only valid on the Convex ExemplarExecution Procedure for ABAQUS/Postabaqus post [ job=job-name ][ restart=restart-name ] [ input=input-file ][ device=device-name ] [ display=display-name ][ geometry=widthXheight+xpos+ypos ][ memory=memory-size ] [ buffer=buffer-size ]Execution Procedure for ABAQUS/Abaresabaqus abares job=job-name [ restart=restart-name ][ beginstep=step-number ] [ endstep=step-number ][ increment={all|endstep|final|none|integer-list} ]Execution Procedure for ABAQUS/Plotabaqus plot job=job-name [ input=input-file ] [ device=device-name ][ frame={all|integer-list} ] [ options=options-file ]Execution Procedure for ASCII translation of results (.fil) filesabaqus ascfil job=job-name [ input=input-file ]Execution Procedure for on-line documentationabaqus docExecution Procedure for ABAQUS/Appendabaqus append job=job-name oldjob=oldjob-name input=input-fileExecution Procedure for ABAQUS/Fetchabaqus fetch job=job-name [ input=input-file ]Execution Procedure for ABAQUS/Findkeywordabaqus findkeyword [ job=job-name ] [ maximum=maximum-matches ]Execution Procedure for ABAQUS/Makeabaqus make job=job-name [ user={source-file|object-file} ](以上的命令很多是不能使用的)Q2.10 : How do I find what the current settings are for the environment variables?Type abaqus info=environment and this will list all the current setting of the ABAQUS environmental variables.memory, local, release, status are other options on which you can get more information on. Abaqus info=localAbaqus info=releaseQ2.11 : How do I change the current settings of theenvironment variables?Create a file called abaqus.env in the directory from which ABAQUS is run which contains lines of environment variables you want to change set equal to new values. However make sure that the computer on which you are running ABAQUS can support the changes. For example you can increase the memory used by ABAQUS. But you cannot increase this beyond what is available in the computer.Example : Include the following lines in the abaqus.env file to increase the size ofpost_buffer and the post_memory used by ABAQUS/Post.post_buffer="1000000"post_memory="3000000"Q2.12 : Can I run long jobs on the twgs?No. it is not a good idea to use the twgs to run long ABAQUS jobs. It is better to use the batch system on one of the faster servers (example : tw900) for long jobs.Also becasue of the limited resources (memory, swap space, scratch disk space) large jobs also cannot be run on the twgs.3. ElementsQ3.1 : How do I find the positive normal of a shell element? For shells the positive normal is given by the right-hand rule going around the nodes of the element in the order they are given in the element-nodal connectivity data line (datalines which follow the keyword *ELEMENT line).If the ABAQUS analysis has been completed then one could use the following command in ABAQUS/Post to get a visual check of the positive normal.set, fill=ondraw, normalsQ3.2 : What is the difference between a shell element and a 2D solid element?The 2D Planar elements (For example : CPE4, CPE8 - plane strain analysis and CP4, CPS8 - plane stress analysis) are only used in situations where the loading is confined to the plane of the elements. The elements only have planar variables (d.o.f) ux, uy.Shell elements are needed for out-of-plane loading. Consider a square plate subjected to a loading normal to the plane of the plate. This requires shell elements and use of planestress/plane strain type of elements would be inappropriate under these circumstances.Shell elements can also be used where the loading is planar but the material is made of composites. Since shell elements by definition allow for through thickness variation of material properties these are the appropriate elements to be used in these cases.Q3.3 : How do I specify the local-1 direction for a beam in space?See the section 6.1.2 of the Getting Started with ABAQUS/Standard manual for a description of this.There are a number of ways of specifying this. In the following figure n1 represents the local-1 direction. Consider a beam element of rectangular cross-section. Then local-1 direction is the direction parallel to the width (or base of the element). See Figure 15.3.4-1 and the figure in Page 15.3.9-15 of the ABAQUS User's manual (Ver 5.7).If the beams all lie in the X-Y plane then by default the negative Z axis is taken as the local-1 direction. The following are the different methods available in specifying the local-1 direction.1.Specify an additional node in the element entry for the beam. If a third node is specifiedthen the direction connecting node 1 to 3 defines the v direction in the above figure. This direction is used as an approximate n1 direction. ABAQUS then defines n2 direction as t x v. Having determined n2, ABAQUS defines the actual n1 direction as n2 x t. Tosummarise as long as v lies in the same plane as the t and n1 vectors no errors areintroduced.2.Specify the approximate n1 direction on the element section option. Then ABAQUS usesthe same procedure as above (method 1) to calculate the n2 direction first and thenre-calculates the n1 direction again which it uses in the analysis.If both the additional node and the n1 direction were specified as part of the section properties then the additional node takes precedence.As mentioned earlier ABAQUS calculates the n2 direction from the t and the approximate n1 directions. There are two methods that can be used to override this.1.Give the components of n2 as the 4th, 5th and the 6th data values following the nodalcoordinates on the data lines of the *NODE option.e the *NORMAL option.If both methods are used then *NORMAL takes precedence. When n2 direction is specified using one of the above methods the beam element tangent t is calculated as n1 x n2.After the ABAQUS analysis has been completed the following commands can be used to check visually the t, n1 and n2 directions.*SET, FILL=ON*VIEW, VIEW=(x1,y1,z1),UP=(x2,y2,z2)Example : *VIEW, VIEW=(1,1.5,2), UP=(0,1,0)*DRAW, NORMALSn1 (beam 1-axis) is shown in blue. n2 (beam 2-axis) is shown in red. t (beam tangent) is shown in white.Q3.4 : Why do you need to specify the local-1 direction for a beam in space?Consider a non-circular cross-section (example : rectangular section). The bending stiffness is affected by which way the width is oriented. local-1 direction fixes the orientation without any ambiguity.Q3.5 : I am having a problem interpreting the stress output from a shell element?If you are using the shell elements (example : S4, S8R5) then you need to be aware that the stresses are defined in local directions which in turn are dependent on the orientation of each element w.r.t the global axes.The Shell element sign convention explains the sign convention for the local directions.4. ABAQUS - MeshQ4.1 : I have created a mesh in two parts separately and have ended up with two sets of node numbers along a common edge. Is there any alternative to editing the *.inp file to replace one set of node numbers by the other set in the element-nodal connectivity list ie element entries?Yes. Use the TIE option available under MPC (Multi Point Constraint) to tie the respective nodes as illustrated in the figure below :*MPCTIE, 100, 200TIE, 101, 201......TIE, 104, 204This would then treat these pair of nodes as identical ie. they will have the same nodal variables. This can also be useful in situations where the mesh used in an axisymmetric analysis is generated from a single surface wrapped around (rather than using the axisymmetric elements available in ABAQUS). See figure below. Then the TIE option could be used along line joining the 2 edges (and the 2 sets of nodes).If there are several such nodes these could be grouped together into sets and the TIE option specified with a single data line. Here the corresponding nodes should appear in the correct order.*NSET, NSET=TOP100, 101, 102, 103, 104*NSET, NSET=BOT200, 201, 202, 203, 204*MPCTIE, TOP, BOTQ4.2 : I have created a mesh but the scale used is wrong. Is it possible to scale the mesh with ABAQUS?This is being investigated.5. ABAQUS - MaterialsQ5.1 : How do I find what material properties are needed for a particular analysis ?Read the relevant section in Chapter 6 : Analysis Types (User's manual Vol. I). This gives an overview about the analysis and has more information about the material properties.Read also the following sections in Chapter 9 : Materials Introduction of the ABAQUS User's manual.∙Section 9.1.1 - Material Library : Overview∙Section 9.1.2 - Material Data Definition∙Section 9.1.3 - Combining Material PropertiesSection 9.1.3 lists the material model combination tables. Several models are available to define the mechanical behaviour (elastic, plastic).Some material options require the presence of other material options. Some exclude the use of the other material options. For example *DEFORMATION PLASTICITY completely defines the material's mechanical behaviour and should not be used with *ELASTIC.Once you have all the relevant keywords to define the material properties consult the keyword section - Chapter 23 (User's manual Volume III) for each of the keywords. This will explain what data is required for each of the keyword.Q5.2 : What material properties need to be specified in a thermal-electrical analysis ?Referring to Section 9.1.3 of the ABAQUS User's manual you will require the heat transfer properties as well as the electrical properties. These are listed below :∙Heat Transfer properties∙*CONDUCTIVITY∙*LATENT HEAT∙*SPECIFIC HEAT∙*HEAT GENERATION∙Electrical properties∙*DIELECTRIC∙*ELECTRICAL CONDUCTIVITY∙*JOULE HEAT FRACTION∙*PIEZOELECTRICThis forms the complete set of properties. If Piezoelectric elements are not used then*PIEZOELECTRIC and *DIELECTRIC properties will not be required.If only the steady state heat transfer response is of interest then *SPECIFIC HEAT properties are not required. Similarly if there are no phase changes involved then *LATENT HEAT is not required.*JOULE HEAT FRACTION is used to specify the fraction of electrical energy that will be released as heat.Example problem 3.2.24 - thermal-electrical modeling of an automotive fuse illustrates the thermal-electrical analysis.ABAQUS allows for redundant material properties to be specified. It will simply ignore the material properties not required for the current analysis.Typical example of material properties :*MATERIAL, NAME=ZINC*CONDUCTIVITY0.1121, 20.00.1103, 100.0*ELECTRICAL CONDUCTIVITY16.75E3, 20.012.92E3, 100.0*JOULE HEAT FRACTION1.0*DENSITY7.14E-6*SPECIFIC HEAT389.0Q5.3 : What material properties need to be specified in an analysis using temperature- displacement elements ?Referring to Section 9.1.3 of the ABAQUS User's manual you will require the heat transfer properties as well as the mechanical properties. These are listed below :∙Mechanical properties∙*ELASTIC∙Additional properties which may be required : example plastic ∙Heat Transfer properties∙*CONDUCTIVITY∙*LATENT HEAT∙*SPECIFIC HEAT∙*HEAT GENERATIONQ5.4 : What material properties need to be specified in an analysis using piezoelectric elements?Referring to Section 9.1.3 of the ABAQUS User's manual you will require the electrical properties. These are listed below :∙Electrical properties∙*DIELECTRIC∙*ELECTRICAL CONDUCTIVITY∙*JOULE HEAT FRACTION∙*PIEZOELECTRICQ5.5 : What material properties need to be specified in modeling concrete with reinforcements?Use the concrete model available with rebar to model the reinforcements.Section 4.2.7 of the ABAQUS Example's manual gives an example of the collapse analysis of a concrete slab subjected to a central point load.The data file for that example is collapse example.*CONCRETE3000., 0. abs. value of compressive stress, abs. value of plastic strain. 5500., 0.0015 " "*FAILURE RATIOS1.16, 0.0836This is used to define the shape of the failure surface (see section 7.6.7 of the ABAQUS USER's manual).The first parameter is the ratio of the ultimate biaxial compression stress, to the uniaxial compressive stress. Default is 1.16.The second parameter is the absolute value of the ratio of uniaxial tensile stress at failure to the uniaxial compressive stress at failure. Default is 0.09.Tension Stiffening*TENSION STIFFENING1., 0.0., 2.E-3First parameter is the fraction of remaining stress to stress at cracking. The second parameter is the absolute value of the direct strain minus the direct strain at cracking.This defines the retained tensile stress normal to the crack as a function of the deformation in thedirection of the normal to the crack.Shear Retention*SHEAR RETENTIONNot used for this example.Reinforcement modelling*REBAR is used to model the reinforcement.*REBAR,ELEMENT=SHELL,MATERIAL=SLABMT,GEOMETRY=ISOPARAMETRIC,NAME=YYSLAB, 0.014875, 1., -0.435, 4*REBAR,ELEMENT=SHELL,MATERIAL=SLABMT,GEOMETRY=ISOPARAMETRIC,NAME=XXSLAB, 0.014875, 1., -0.435, 1Here SLAB is the element name or name of the element set that contains these rebars. The geometry is ISOPARAMETRIC. Other choice is SKEW. ELEMENT can be BEAM, SHELL, AXISHELL or CONTINUUM type. The following are the other parameters specified :∙cross-sectional area of the rebar.∙spacing of the rebars in the plane of the shell∙position of the rebar. Distance from the reference surface. Here the mid-surface is the reference surface and the minus sign indicates that the distance is measured in theopposite direction to the direction of positive normal. The positive normal is defined bythe right hand rule as the nodes are considered in an anti-clockwise sequence.∙edge number to which rebars are similar.Q5.6 : What material properties need to be specified in using the deformation plasticity model ?See section 11.2.9 of the users' manual (Vol. I). See also section 23.4.7 of the users' manual (Vol. III), keyword section.For example :*DEFORMATION PLASTICITY1.E3, 0.3,2., 3, 0.396Here the data line contains the Young's modulus, Poissons ratio, Yield stress, Exponent, Yield offset respectively. If it is necessary to define the dependence of these parameters on temperature then the 6th parameter will be the temperature. Then repeat the dataline for different temperatures as required.6. ABAQUS - Boundary ConditionsQ6.1 : How do I change the boundary conditions at some of the nodes?Re-specify the boundary condition for only the nodes for which the boundary condition has changed with the OP=NEW option.*BOUNDARY, OP=NEW1, 1,, 2.52, 1,, 2.53, 1,, 2.5In the above example the x-displacement is changed to be 2.5 units at nodes 1, 2 and 3.Q6.2 : How do I completely re-define the boundary conditions?Same as above (see the answer to question 6.1).Q6.3 : How do I release a previously fixed d.o.f.?Re-specify all the fixities except for the ones to be released (in the step in which these fixities are to be released) with the parameter OP=MOD.Q6.4 : How do I apply a prescribed displacement?Use the keyword *BOUNDARY and in the data line specify the node number, variable (d.o.f.) number and the magnitude of the prescribed displacement. It will require one dataline per variable that is being prescribed.*BOUNDARY, OP=NEW1, 1,, 2.52, 1,, 2.53, 1,, 2.5In this example nodes 1, 2 and 3 are applied a displacement of 2.5 units in the direction of the first axis (usually X axis).Q6.5 : Are there any default boundary conditions representing "pinned" and "encastred" nodes that can be used?Yes. The following is the list of named constraints.ENCASTRE Constraint on all displacements and rotations at a node.PINNED Constraint on all translational degrees of freedom.XSYMM Symmetry constraint about a plane of constant x coordinate.YSYMM Symmetry constraint about a plane of constant y coordinate.ZSYMM Symmetry constraint about a plane of constant z coordinate. XASYMM Antisymmetry constraint about a plane of constant x coordinate. YASYMM Antisymmetry constraint about a plane of constant y coordinate. ZASYMM Antisymmetry constraint about a plane of constant z coordinate. Example :*NGEN, NSET=FIXED1, 10*BOUNDARYFIXED, ENCASTREHere a node set which consists of 10 nodes grouped together in node set FIXED is assigned the ENCASTRE boundary condition.Example :*NODE1, 134.0, 0.0, 28.5201, 134.0, 28.5, 0.0***NGEN, LINE=C,NSET=CLAMPED1, 201, 40***BOUNDARYCLAMPED, XSYMMA node set called CLAMPED which consists of nodes 1, 41, ..., 201 which lie along a circular arc is first created. Then the XSYMM boundary condition is specified.Q6.6 : What are the variable numbers for the different nodal variables?Following is a list of the more common variable numbers.1,2,3 - x,y,z displacement respectively (ux, uy, uz)1,2 - r,z displacement in an axisymmetric analysis (ur, uz)4,5,6 - Rotation about x,y,z axes respectively (phi_x, phi_y, phi_z)6 - Rotation in the r-z plane for axisymmetric shells7 - warping amplitude (for open section beam elements)8 - Pore pressure9 - Electric potential11 - Temperature12 - Second temperature (for shells or beams)13 - Third temperature (for shells or beams)14 - Etc.Q6.7 : Is it possible to connect different element typestogether in the same mesh ?Yes there are no restrictions in connecting different element types together in a mesh. Any restriction you are likely to come across is inappropriate use of element types in certain analysis (procedures).Q6.8 : Is it possible to apply boundary conditions w.r.t. local axes?Yes it is possible to apply boundary conditions w.r.t local co-ordinate axes. Consider the situation where you want to apply a rotation at a set of nodes which lie along the periphery of a circular arc.Consider the figure where nodes 1 to 5 along the outer radius are to be subjected to a rotation of 1 unit. Then a local cylindrical co-ordinate system transformation is set up first. The nodes 1 to 5 are formed into an element set called CID1. The transform keyword is used to apply the transformation to the node set CID1 as follows :*TRANSFORM, TYPE=C, NSET=CID10., 0., 0., 0., 0., 1.***NSET, NSET=CID11, 2, 3, 4, 5****** rotation boundary condition***BOUNDARY CONDITION, OP=NEW1, 5, 1.2, 5, 1.3, 5, 1.4, 5, 1.5, 5, 1.The applied rotation is interpreted according to the transformation.。