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有限元三杆桁架优化分析报告

考试题目:下图所示为一个有3根杆组成的桁架,承受纵向和横向载荷,试对该结构进行优化设计,使得桁架重量最少。

系学数K=班号(为5,6,7,8之一)×100+学号最后两位数,如7班同学,号最后两位为20号,那么K=720已知桁架的材料特性为:弹性模量E=0.5K×103MPa;泊松比:0.5K×10-3;密度ρ= K×10 kg/m3许用应力:σ=0.5K×10-2MPa几何属性如下所示:横截面面积变化范围:0.6×10-3~0.645m2)基本尺寸B变化范围:10~0.5K×10-1m集中载荷为:Fx= 2K×103N, Fy= -2K×103N要求:写出操作步骤和命令流,定义工作文件名和工作标题为你的姓名拼音+学号。

GUI操作方式(1)定义工作文件名及工作标题1)定义工作文件名2)定义工作标题(2)定义参数和材料属性定义参数的初始值2)设置材料属性(3)定义单元类型及属性1)定义单元类型定义实常数A2 A3同A1做法(4)建立有限元模型1)生成有限元节点(节点1 2 3 4做法雷同)2)关闭坐标符号的显示3)打开节点编号显示4)生成第一个单元5)改变第二个单元的属性6)生成第二个单元7)改变第三个单元的属性8)生成第三个单元(5)施加约束和载荷1)施加边界约束2)施加集中载荷3)保存数据4)求解运算结果如下:S O L U T I O N O P T I O N SPROBLEM DIMENSIONALITY. . . . . . . . . . . . .2-DDEGREES OF FREEDOM. . . . . . UX UYANALYSIS TYPE . . . . . . . . . . . . . . . . .STATIC (STEADY-STATE) GLOBALLY ASSEMBLED MATRIX . . . . . . . . . . .SYMMETRICL O A D S T E P O P T I O N SLOAD STEP NUMBER. . . . . . . . . . . . . . . . 1TIME AT END OF THE LOAD STEP. . . . . . . . . . 1.0000NUMBER OF SUBSTEPS. . . . . . . . . . . . . . . 1STEP CHANGE BOUNDARY CONDITIONS . . . . . . . . NOPRINT OUTPUT CONTROLS . . . . . . . . . . . . .NO PRINTOUTDATABASE OUTPUT CONTROLS. . . . . . . . . . . .ALL DATA WRITTENFOR THE LAST SUBSTEP 5)保存优化结果到文件(6)进入后处理,得到状态变量和目标函数的值1)定义单元表2)计算单元体积的总和结果如下:SUM ALL THE ACTIVE ENTRIES IN THE ELEMENT TABLETABLE LABEL TOTALVOLU 65.43743)取出体积的值4)计算初始重量5)设置单元表6)得到第一杆的轴向应力7)得到第二杆的轴向应力8)得到第三杆的轴向应力9)计算轴向力的绝对值(7)显示当前设计并生成分析文件1)显示杆的当前设计2)改变视图方向3)生成优化分析文件(8)进入处理器并分析文件1)指定分析文件2)指定设计变量(A1 A2 A3 B做法雷同)3)设置状态变量3)保存优化数据库4)设置目标函数5)指定一阶优化方法6)保存数据7)运行优化8)保存优化结果到文件(9)查看优化结果1)查看最佳设计序列如下:LIST OPTIMIZATION SETS FROM SET 10 TO SET 10 AND SHOW ONLY OPTIMIZATION PARAMETERSSET 10(FEASIBLE)SIG1 (SV) 0.26212E+07SIG2 (SV) 65340.SIG3 (SV) 0.25491E+07A1 (DV) 0.57422A2 (DV) 0.60000E-03A3 (DV) 0.30810E-01B (DV) 23.873WT (OBJ) 114.462)列出所有序列的结果如下:LIST OPTIMIZATION SETS FROM SET 1 TO SET 10 AND SHOWONLY OPTIMIZATION PARAMETERS. (A "*" SYMBOL IS USED TO INDICATE THE BEST LISTED SET)SET 1 SET 2 SET 3 SET 4(FEASIBLE) (FEASIBLE) (FEASIBLE) (FEASIBLE)SIG1 (SV) 0.16434E+07 0.24929E+07 0.25179E+07 0.24641E+07 SIG2 (SV) 0.96269E+06 0.12070E+07 0.20381E+06 50744. SIG3 (SV) 0.68072E+06 0.11304E+07 0.22835E+07 0.24060E+07 A1 (DV) 0.64500 0.44325 0.58658 0.61001A2 (DV) 0.64500 0.50234 0.26012 0.23868A3 (DV) 0.64500 0.44325 0.65182E-01 0.49212E-01 B (DV) 26.500 23.282 22.787 22.891WT (OBJ) 346.82 236.29 157.26 155.87SET 5 SET 6 SET 7 SET 8(FEASIBLE) (FEASIBLE) (FEASIBLE) (FEASIBLE)SIG1 (SV) 0.24181E+07 0.25032E+07 0.24888E+07 0.25939E+07 SIG2 (SV) 0.15564E+06 0.10283E+07 0.11761E+07 0.11863E+06 SIG3 (SV) 0.22407E+07 0.13731E+07 0.12008E+07 0.24629E+07 A1 (DV) 0.61469 0.59326 0.60418 0.58028A2 (DV) 0.23115 0.28213E-01 0.60000E-03 0.60000E-03 A3 (DV) 0.58005E-01 0.68621E-01 0.60115E-01 0.32016E-01 B (DV) 23.020 23.995 24.088 23.863WT (OBJ) 157.61 129.37 126.17 115.81SET 9 *SET 10*(FEASIBLE) (FEASIBLE)SIG1 (SV) 0.26140E+07 0.26212E+07SIG2 (SV) 0.19452E+06 65340.SIG3 (SV) 0.23994E+07 0.25491E+07A1 (DV) 0.57577 0.57422A2 (DV) 0.60000E-03 0.60000E-03A3 (DV) 0.32593E-01 0.30810E-01B (DV) 23.885 23.873WT (OBJ) 115.11 114.463)显示目标函数的变化规律a设置坐标轴标题b显示目标函数的变化规律4)显示基本尺寸B的变化规律a设置坐标轴标题b显示基本尺寸的变化规律5)显示杆面积的变化规律a 设置坐标标题b 显示杆横截面的变化规律6)显示杆中应力的变化规律a设置坐标轴标题b显示杆中应力的变化规律(10)退出ANSYS命令流方式:/BATCH/FILNAME,zhangliwen+201000104030,1 /TITLE,zhangliwen+201000104030*SET,B,26.5*SET,A1,0.645*SET,A2,0.645*SET,A3,0.645/PREP7 MPTEMP,,,,,,,,MPTEMP,1,0MPDATA,EX,1,,2.65e11MPDATA,PRXY,1,,0.265 MPTEMP,,,,,,,,MPTEMP,1,0MPDATA,DENS,1,,5.3ET,1,LINK1R,1,A1, ,R,2,A2, ,R,3,A3, ,N,1,-B,0,0,,,,N,2,0,0,0,,,,N,3,B,0,0,,,,N,4,0,-26.5,0,,,,/PLOPTS,INFO,3 /PLOPTS,LEG1,1 /PLOPTS,LEG2,1 /PLOPTS,LEG3,1 /PLOPTS,FRAME,1 /PLOPTS,TITLE,1 /PLOPTS,MINM,1 /PLOPTS,FILE,0/PLOPTS,LOGO,1 /PLOPTS,WINS,1 /PLOPTS,WP,0/PLOPTS,DATE,2 /TRIAD,OFF/REPLOT/PNUM,KP,0/PNUM,LINE,0 /PNUM,AREA,0 /PNUM,VOLU,0 /PNUM,NODE,1 /PNUM,TABN,0 /PNUM,SVAL,0 /NUMBER,0/PNUM,ELEM,0 /REPLOT FLST,2,2,1 FITEM,2,1 FITEM,2,4E,P51X TYPE,1 MAT,1 REAL,2 ESYS,0 SECNUM, TSHAP,LINE FLST,2,2,1 FITEM,2,2 FITEM,2,4E,P51XTYPE,1MAT,1REAL,3 ESYS,0 SECNUM, TSHAP,LINE FLST,2,2,1 FITEM,2,3 FITEM,2,4E,P51XFINISH/SOLFLST,2,3,1,ORDE,2 FITEM,2,1 FITEM,2,-3D,P51X,ALL, FLST,2,1,1,ORDE,1 FITEM,2,4F,P51X,FX,1.06e6 FLST,2,1,1,ORDE,1 FITEM,2,4F,P51X,FY,-1.06e6 SAVE/STATUS,SOLUSOLVESAVE,'zhangliwen_201000104030','db','C:\DOCUME~1\ADMINI~1\' FINISH/POST1AVPRIN,0,ETABLE,EVOLUME,VOLU,SSUM*GET,VTOT,SSUM, ,ITEM,EVOLUME*SET,DENS,5.3*SET,WT,DENS*VTOTAVPRIN,0, ,ETABLE,SIGMA,LS,1*GET,sig1,ELEM,1,ETAB,SIGMA*GET,sig2,ELEM,2,ETAB,SIGMA*GET,sig3,ELEM,3,ETAB,SIGMA*SET,sig1,abs(sig1)*SET,sig2,abs(sig2)*SET,sig3,abs(sig3)/SHRINK,0/ESHAPE,2/EFACET,1/RATIO,1,1,1/CFORMAT,32,0/REPLOT/VIEW,1,1,1,1/ANG, 1/REP,FASTEPLOTLGWRITE,'zhangliwen_201000104030','lgw','C:\DOCUME~1\ADMINI~1\',COMMENT FINISH/OPTOPANL,'zhangliwen_201000104030','lgw','OPVAR,A1,DV,0.6e-3,0.645, ,OPVAR,A2,DV,0.6e-3,0.645, ,OPVAR,A3,DV,0.6e-3,0.645, ,OPVAR,B,DV,10,26.5, ,OPVAR,SIG1,SV, ,2.65E6, ,OPVAR,SIG2,SV, ,2.65E6, ,OPVAR,SIG3,SV, ,2.65E6, ,OPSAVE,'zhangliwen_var','opt',' 'OPVAR,WT,OBJ, , ,1,SAVEOPTYPE,FIRSOPFRST,15, , ,SAVEOPEXE! OPTIMIZATION LOOPING HAS CLEARED THE INTERNAL LOG KEYW,BETA,0SAVESAVE,'zhangliwen_opt_resu','db','C:\DOCUME~1\ADMINI~1\' OPLIST,16, ,0OPLIST,ALL, ,0/VIEW,1,,,1/AXLAB,X,Iteration Number/AXLAB,Y,Structural Weight/GTHK,AXIS,2/GRTYP,0/GROPT,ASCAL,ON/GROPT,LOGX,OFF/GROPT,LOGY,OFF/GROPT,AXDV,1/GROPT,AXNM,ON/GROPT,AXNSC,1,/GROPT,DIG1,4,/GROPT,DIG2,3,/GROPT,XAXO,0,/GROPT,YAXO,0,/GROPT,DIVY,/GROPT,REVX,0/GROPT,REVY,0/GROPT,LTYP,0/XRANGE,DEFAULT/YRANGE,DEFAULT,,1 XVAROPT,' ' PLVAROPT,WT/AXLAB,X,Iteration Number /AXLAB,Y,Base Dimension /GTHK,AXIS,2/GRTYP,0/GROPT,ASCAL,ON/GROPT,LOGX,OFF/GROPT,LOGY,OFF/GROPT,AXDV,1/GROPT,AXNM,ON/GROPT,AXNSC,1,/GROPT,DIG1,4,/GROPT,DIG2,3,/GROPT,XAXO,0,/GROPT,YAXO,0,/GROPT,DIVY,/GROPT,REVX,0/GROPT,REVY,0/GROPT,LTYP,0/XRANGE,DEFAULT/YRANGE,DEFAULT,,1 XVAROPT,' 'PLVAROPT,B/AXLAB,X,Iteration Number/AXLAB,Y,Cross_Sec-tional Area /GTHK,AXIS,2/GRTYP,0/GROPT,ASCAL,ON/GROPT,LOGX,OFF/GROPT,LOGY,OFF/GROPT,AXDV,1/GROPT,AXNM,ON/GROPT,AXNSC,1,/GROPT,DIG1,4,/GROPT,DIG2,3,/GROPT,XAXO,0,/GROPT,YAXO,0,/GROPT,DIVY,/GROPT,REVX,0/GROPT,REVY,0/GROPT,LTYP,0/XRANGE,DEFAULT/YRANGE,DEFAULT,,1 XVAROPT,' ' PLVAROPT,A1,A2,A3/AXLAB,X,Iteration Number /AXLAB,Y,Maximum Stress /GTHK,AXIS,2/GRTYP,0/GROPT,ASCAL,ON/GROPT,LOGX,OFF/GROPT,LOGY,OFF/GROPT,AXDV,1/GROPT,AXNM,ON/GROPT,AXNSC,1,/GROPT,DIG1,4,/GROPT,DIG2,3,/GROPT,XAXO,0,/GROPT,YAXO,0,实用标准文案/GROPT,DIVX,/GROPT,DIVY,/GROPT,REVX,0/GROPT,REVY,0/GROPT,LTYP,0/XRANGE,DEFAULT/YRANGE,DEFAULT,,1XVAROPT,' 'PLVAROPT,SIG1,SIG2,SIG3SAVE/DIST,1,1.08222638492,1/REP,FAST/DIST,1,1.08222638492,1/REP,FASTSAVEFINISH精彩文档。

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