ANSYS荷载工况组合计算实例1相关命令1.1LCDEF1.2LCFACT1.3SUMTYPE1.4LCOPER1.5LCASE11.6LCWRITE1.7其他命令2实例在实际工程计算中,往往需要分析多种不同荷载组合总用下的结构响应,比如恒载、活荷载、风荷载等的组合,有些是荷载位置不同,有些则是荷载大小差异。ANSYS做不同荷载工况组合分析,要么是每一种工况用单独的APDL进行运算,每个工况一套文件;要么就是利用分析结果,在一个计算文件中,用不同的荷载步定义荷载组合,再用工况组合功能来实现我们的分析目标。下面总结一下实现荷载工况组合的方法1.相关命令1.1.LCDEFLCDEF,LCNO,LSTEP,SBSTEP,KIMG从结果文件中创建一个工况其中常用参数为:LCNO工况编号,是1~99之间的一个数字,作为指针,将工况与计算文件中的荷载步和荷载子步联系起来LSTEP用于定义工况的荷载步SBSTEP用于定义工况的荷载子步,默认为荷载步的最后一个子步KIMG用于复数分析,0-用实部;1-用虚部1.2.LCFACTLCFACT,LCNO,FACT定义工况的分项系数其中,Lcno为工况编号,fact为分项系数1.3.SUMTYPESUMTYPE,Label为工况组合设置数据组合类型Lable参数有两个选项,分别为COMP—Combineelementcomponentstressesonly.Stressessuchasaveragenodalstresses,principalstresses,equivalentstresses,andstressintensitiesarederivedfromthecombinedelementcomponentstresses.Default.此选项为只将单元应力进行组合,节点平均应力、主应力、等效应力等则从组合后的单元应力中求解(不知道这样理解是否合适呢。。。)PRIN—Combineprincipalstress,equivalentstress,andstressintensitydirectlyasstoredontheresultsfile.Componentstressesarenotavailablewiththisoption.对主应力、等效应力、应力强度等直接根据结果文件进行组合。所以平时在计算主应力等结果时候多用次选项。1.4.LCOPERLCOPER,Oper,LCASE1,Oper2,LCASE2对荷载工况进行操作OperZERO—Zeroresultsportionofdatabase(LCASE1ignored).结果数据库中为零的部分?SQUA—Squaredatabasevalues(LCASE1ignored).数据结果取平方SQRT—Squarerootofdatabase(absolute)values(LCASE1ignored).结果数据开平方根LPRIN—Recalculatelineelementprincipalstresses(LCASE1ignored).StressesareasshownfortheNMISCitemsoftheETABLEcommandforthespecificlineelementtype.计算线性主应力ADD—AddLCASE1todatabasevalues.将工况1增加到求解数据库中SUB—SubtractLCASE1fromdatabasevalues.将工况1从求解数据库中删除SRSS—SquarerootofthesumofthesquaresofdatabaseandLCASE1.将求解数据库和工况1之和进行开平方MIN—CompareandsaveindatabasethealgebraicminimumofdatabaseandLCASE1.将数据库和工况1中的代数比较小者存入现有数据库MAX—CompareandsaveindatabasethealgebraicmaximumofdatabaseandLCASE1.将数据库和工况1中的代数较大者存入现有数据库ABMN—CompareandsaveindatabasetheabsoluteminimumofdatabaseandLCASE1(basedonmagnitudes,thenapplythecorrespondingsign).将数据库和工况1中绝对值较小者存入现有数据库ABMX—CompareandsaveindatabasetheabsolutemaximumofdatabaseandLCASE1(basedonmagnitudes,thenapplythecorrespondingsign).将数据库和工况1中绝对值较大者存入现有数据库1.5.LCASE1Firstloadcaseintheoperation(ifany).SeeLCNOoftheLCDEFcommand.IfALL,repeatoperationsusingallselectedloadcases.工况运算的第一个工况,由LCDEF命令指定,如果为all,则对所有已选择的工况重复命令。Oper2MULT—乘法运算:LCASE1*LCASE2CPXMAX—此选项用于复数运算,将工况1作为实部,工况2作为虚部。ThisoptiondoesaphaseanglesweeptocalculatethemaximumofderivedstressesandequivalentstrainforacomplexsolutionwhereLCASE1istherealpartandLCASE2istheimaginarypart.TheOperfieldisnotapplicablewiththisoption.Also,theLCABSandSUMTYPEcommandshavenoeffectonthisoption.ThevalueofS3willbeaminimum.Thisoptiondoesnotapplytoderiveddisplacementamplitude(USUM).Loadcasewriting(LCWRITE)isnotsupported.SeePOST1andPOST26–ComplexResultsPostprocessingintheMechanicalAPDLTheoryReferenceformoreinformation.LCASE2Secondloadcase.UsedonlywithOper2operations.1.6.LCWRITELCWRITE,LCNO,Fname,Ext,—创建工况文件其中lcno为工况编号,fname和ext分别为工况文件名称和后缀名1.7.其他命令lCDEF,ERASE来删除所有的荷载工况指针和所有的荷载工况文件LCDEF,LCNO,ERASE删除指定的荷载工况指针LCNO(和相应的文件)。LCDEF,STAT查看所有选定的荷载工况(LCSEL)的状态LCDEF,STAT,ALL查看所有荷载工况的状态LCSEL,Type,LCMIN,LCMAX,LCINC选择指定编号的工况2.实例首先要说明,这个悬臂梁实例本身没有任何工程意义,只是用来熟悉一下相关操作而已。为了便于理解,实例中只有两个荷载工况,分别为向上的集中力和向下的均布荷载,实际情况可能比实例中更复杂,就需要具体问题具体分析了。/悬臂梁简单模型finish/clear/prep7et,1,188mp,ex,1,2.1e5mp,prxy,1,0.3sectype,1,beam,I,,0secdata,0.5,0.5,0.7,0.05,0.05,0.05k,1,k,2,10k,3,,20l,1,2latt,1,1,1,,3,,1lesize,all,1lmesh,all/solud,1,allf,2,fy,100lswrite,1fdele,all,allsfbeam,all,,pres,200,200lswrite,2allsel,alloutpr,all,alllssolve,1,2,1!对各荷载独立求解finish/post1/eshape,1plnsol,s,1对上述命令流进行改进,设置荷载组合:finish/clear/prep7et,1,188mp,ex,1,2.1e5mp,prxy,1,0.3sectype,1,beam,I,,0secdata,0.5,0.5,0.7,0.05,0.05,0.05k,1,k,2,10k,3,,20l,1,2latt,1,1,1,,3,,1lesize,all,1lmesh,all/solud,1,allf,2,fy,100lswrite,1fdele,all,allsfbeam,all,,pres,200,200lswrite,2allsel,alloutpr,all,alllssolve,1,2,1!对各荷载独立求解finish/post1/eshape,1!plnsol,s,1/post1lcdef,1,1!设定工况1=荷载步1,工况2=荷载步2lcdef,2,2!给两个工况设置不同的分项系数lcfact,1,1.2lcfact,2,1.4lcase,1!读入工况1,database=1sumtype,prin!指定加操作的类型lcoper,add,2!荷载组合,database=database+2lcoper,lprin!计算线性主应力lcwrite,11!把database结果写到工况11,即1.2倍竖向力+1.4倍均布荷载lcase,1!还可以重新读入工况1,database=1lcfact,1,2!重新定义分项系数lcfact,2,1.5sumtype,prinlcoper,add,2!荷载组合,database=database+2lcoper,lprin!计算线性主应力lcwrite,12!把database结果写到工况11,即2倍竖向力+1.5倍均布荷载lcase,1!载入工况1plnsol,s,1!查看该工况下的结构响应荷载工况1的SX计算结果荷载工况2的SX计算结果ansys荷载工况组合若用ANSYS进行设计,往往要计算很多种工况组合,如果加载能分开加载独立计算然后结果叠加(仅限于弹性阶段)则效率可提高不少,下面推荐几个命令即可达到这种效果。!★加自重——————————————————★1★allsel,allacel,0,0,0fdele,all,all,allsfadele,all,all,allacel,,,10lswrite,1allsel,all………………lswrite,N_LOAD!可加其他荷载,自己定义allsel,alloutpr,all,alllssolve,1,N_LOAD,1!对各荷载独立求解fini!荷载组合/post1allsel,alllcase,1!读出自重荷载下的结构响应lcoper,add,2!加上荷载2lcwrite,31!作为工况组合31当然可以用lcfact定义荷载的分项系数,再进行组合。善用这些命令,对于设计(往往是很多工况组合)就比较方便了对单层或二层框架进行弹性分析,需要考虑四种荷载恒荷载,活荷载,风荷载和吊车荷载1,几何模型(beam3和beam54)建立后,定义所需的elementtable,主要包括杆端力和最大应力,最小应力等。然后保存数据库。分别施加四种荷载的标准值(不乘分项系数),并分别存成四个loadstepfile。2,使用solution-fromlsfiles,求解四种荷载3,荷载组合,命令流如下:/post1lcdef,1,1lcdef,2,2lcdef,3,3lcdef,4,4!定义四种工况,分别为四种荷载下的计算结果lcfact,1,1.2lcfact,2,1.4lcfact,3,1.19lcfact,4,1.4!指定各工况的组合系数