ANSYS-优化设计(含几个实例)

7ANSYS 优化设计1.认识ANSYS优化模块1.1 什么时候我需要它的帮忙?什么是ANSYS优化？我想说明一个例子要比我在这里对你絮叨半天容易理解的多。注意过普通的水杯吗？底面圆圆的，上面加盖的哪一种。仔细观察一下，你会发现比较老式的此类水杯有一个共同特点：底面直径水杯高度。图1 水杯的简化模型为什么是这样呢？因为只有满足这个条件，才能在原料耗费最少的情况下使杯子的容积最大。在材料一定的情况下，如果水杯的底面积大，其高度必然就要小；如果高度变大了，底面积又大不了，如何调和这两者之间的矛盾？其实这恰恰就反应了一个完整的优化过程。在这里，一个水杯的材料是一定的，所要优化的变量就是杯子底面的半径r和杯子的高度h，在ANSYS的优化模块里面把这些需要优化的变量叫做设计变量（DV）；优化的目标是要使整个水杯的容积最大，这个目标在ANSYS的优化过程里叫目标函数（OBJ）；再者，对设计变量的优化有一定的限制条件，比如说整个杯子的材料不变，这些限制条件在ANSYS的优化模块中用状态变量（SV）来控制。下面我们就来看看ANSYS中怎么通过设定DV、SV、OBJ，利用优化模块求解以上问题。首先参数化的建立一个分析文件（假设叫volu.inp），水杯初始半径为R1，高度为H1（DV），由于水杯材料直接喝水杯的表面积有关系，这里假设水杯表面积不能大于100，这样就有S2RH2R2 SOLUTION HAS CONVERGED TO POSSIBLE OPTIMUM (BASED ON OBJ TOLERANCE BETWEEN BEST AND FINAL DESIGNS)可见是因为导致循环提前结束。（注：细观上图，Fj=157.20，Fb=151.62，默认公差似乎此处应该是1.5720，似乎还没有满足这个收敛准则，为什么ANSYS却认为满足了，这里就不得而知，可能ANSYS内部对默认公差里面的当前值另有解释；如果你强行规定目标函数公差为1，可以看到循环多进行一步后也会提前结束，不过这时候当前解151.65和最优解151.62倒的确相差小于公差1了）。此时，大家一定可以理解例子中为什么要对公差的限制如此严谨了（0.01）。因为程序的取样，迭代都有随机性，只有这样，才能保证程序不会因为上述公差太大的缘故自动停止而得不到最优解。有兴趣的同学还可以改变一下其他参数的公差大小，甚至用opsubp命令改变默认循环的次数等，这些实验将会更加加深你对优化过程、收敛准则的理解，便于提高你都负责优化问题的驾驭能力。拓扑优化实例/clear/TITLE, A 2-D, multiple compliance minimization problem subjected to volume constraint/PREP7 BLC4,0,0,3,1 ! Create solid model (3 x 1 rectangle)ET,1,82 ! Use 2-D solids. Type 1 is optimizedET,2,82 ! Type 2 is not optimized.MP,EX,1,118E9 ! Linear isotropic, materialMP,NUXY,1,0.3ESIZE,0.05 ! Use a relatively fine mesh densityTYPE,1AMESH,ALL ! Free, rectangular-element meshingNSEL,S,LOC,X,0,0.4 ! Select region not to be optimizedESLNTYPE,2EMODIF,ALL ! Define type 2 elementsALLSEL NSEL,S,LOC,X,0D,ALL,ALL,0 ! Fixed at X = 0NSEL,S,LOC,X,3D,ALL,ALL,0 ! Fixed at X = 3FORCE = 1000 ! Value for applied loadNSEL,S,LOC,X,1NSEL,R,LOC,Y,1F,ALL,FY,FORCE ! Define first load caseALLSELLSWRITE,1 ! Write first load caseFDEL,ALLNSEL,S,LOC,X,2NSEL,R,LOC,Y,0F,ALL,FY,-FORCE ! Define second load caseALLSELLSWRITE,2 ! Write second load caseFDEL,ALLTOCOMP,MCOMP,MULTIPLE,2 ! Define multiple compliance function ! MCOMP for topological optimizationTOVAR,MCOMP,OBJ ! Define MCOMP as topological objective TOVAR,VOLUME,CON,50 ! Define VOLUME as topological constraint; 50 percent volume reductionTOTYPE,OC ! Specify solution approach TODEF ! Initialize topological opt. /SHOW,topo,grph ! Put graphics in a file (remove if interactive)/DSCALE,OFF/CONTOUR,2TOLOOP,12,1 ! Perform no more than 12 iterationsFINISHTOGRAPH,OBJ ! Graph final objective (compliance) historyTOGRAPH,CON ! Graph final constraint (volume) historyTOPRINT,OBJ ! Print final objective (compliance) historyTOPRINT,CON ! Print final constraint (volume) history*GET,TITER,TOPO,ITER ! Get iteration counter*GET,OCMP,TOPO,TITER-1,TOHO ! Get final compliance value22第3例 复杂形状实体的创建实例螺栓本例提示 在使用ANSYS软件进行结构分析时，建立实体模型是最复杂最难以掌握的一个过程。因此，有必要熟练掌握实体模型的创建。本例使用ANSYS软件提供的各种建模工具，对复杂形状实体的创建进行了练习。/PREP7CSYS,1K,1,0.008,0,-0.002K,2,0.008,90,-0.0015K,3,0.008,180,-0.001K,4,0.008,270,-0.0005K,5,0.008,0,0/VIEW,1,1,1,1L,1,2L,2,3L,3,4L,4,5LGEN,7,ALL,0.002NUMMRG,KP,LOWLCOMB,ALLK,80,0.008+0.0015/4,90,0.012+0.002/4K,81,0.008+2*0.0015/4,180,0.012+2*0.002/4K,82,0.008+3*0.0015/4,270,0.012+3*0.002/4K,83,0.008+4*0.0015/4,0,0.012+4*0.002/4L,35,80L,80,81L,81,82L,82,83CSYS,0K,90,0.008,0,-0.00025K,91,0.006918,0,-0.002K,92,0.006918,0,0/PNUM,KP,1 /PNUM,LINE,1GPLOTLSTR,1,90 LSTR,91,92LANG,7,90,60,0LANG,7,1,120,0AL,6,9,10,11VDRAG,1,1,2,3,4,5/PNUM,KP,0 /PNUM,LINE,0/PNUM,AREA,1/PNUM,VOLU,1CYLIND,0.0079,0,0.04,0,360VSEL,U,6CM,VVV2,VOLUALLSVSBV,6,VVV2/REPLOTK,93,0.0065,0,0K,94,0.0095,0,0.003K,95,0,0,0K,96,0,0,0.03LSTR,93,94AROTAT,6,95,96,360ASEL,S,1,4,1VSBA,7,ALLASEL,ALLVDELE,1,1RPRISM,0.04,0.05,6,0.0131CONE,0.03477,0.00549,0.03,0.055,0,360VINV,1,3/REPLOTVPLOTFINISH第26例 优化设计实例梁的优化设计本例提示 介绍了优化设计的相关理论和应用，讲述了将设计问题的物理模型转化为数学模型选取设计变量、写出目标函数、给出约束条件的方法。 1. 优化分析文件!File：EXAMPLE26.LGWH=0.06B=0.06L=1/PREP7ET,1, BEAM3R,1,B*H,B*H*H*H/12,HMP,EX,1,2E11MP,NUXY,1,0.3K,1,0,0,0K,2,L,0,0LSTR,1,2LESIZE,1,50LMESH,1FINISH/SOLUDK,1,UXDK,1,UYDK,2,UXDK,2,UYSFBEAM,ALL,1,PRES,5000SOLVESAVEFINISH/POST1ETABLE,E_VOL,VOLUSSUM*GET,V_TOT,SSUM,ITEM,E_VOLNSORT,U,Y *GET,UY_MIN,SORT,MINUY_MAX=ABS(UY_MIN)FINISH2. 优化控制文件!File：EXAMPLE26_OPT.TXT/FILNAME, EXAMPLE26/OPTOPCLRFINISH/CLEAR/INPUT, EXAMPLE26,LGW/OPTOPANL, EXAMPLE26,LGWOPVAR,B,DV,0.05,0.1,0.001OPVAR,H,DV,0.05,0.1,0.001OPVAR,UY_MAX,SV,0,2E-4,1E-5OPVAR,V_TOT,OBJ,1E-5OPSAVE, EXAMPLE26,OPTOPTYPE, FIRSTOPFRST,30OPEXECOPLIST,ALLFINISH3. 求解方法先分别以文件名EXAMPLE26.LGW、EXAMPLE26_OPT.TXT将优化分析文件和优化控制文件存储在ANSYS的工作文件夹里，再在ANSYS的输入窗口输入/ INPUT, EXAMPLE26_OPT,TXT，回车，开始求解。第27例 优化设计实例曲柄摇杆机构的优化设计本例提示 介绍了一个更复杂、更接近于实际的优化设计实例。1. 优化分析文件!File：EXAMPLE27.LGWPI=3.1415926 A=2B=8C=7.5D=9.5AX=1AY=4BATA_OPT=PI/16K=7GAMA=PI/3!建立有限元模型/PREP7BATA=BATA_OPT-PI/2OMGA1=0.5T=60/OMGA1ET,1,COMBIN7ET,2,BEAM4MP,EX,1,2E11MP,PRXY,1,0.3MP,DENS,1,1E-14R,1,1E9,1E3,1E3,0R,2,4E-4,1.3333E-8,1.3333E-8,0.02,0.02COS_SETA1=(A+B)*(A+B)+D*D-C*C)/2/(A+B)/D*IF,COS_SETA1,GE,-1,AND,COS_SETA1,LE,1,THENSETA1=ACOS(COS_SETA1)*ELSESETA1=0*ENDIFBX=AX+A*COS(SETA1+BATA)BY=AY+A*SIN(SETA1+BATA)CX=BX+B*COS(SETA1+BATA)CY=BY+B*SIN(SETA1+BATA)DX=AX+D*COS(BATA)DY=AY+D*SIN(BATA)KX=BX+K*COS(BATA+SETA1+GAMA)KY=BY+K*SIN(BATA+SETA1+GAMA)N,1,AX,AYN,2,BX,BY N,3,BX,BYN,4,CX,CYN,5,CX,CYN,6,DX,DYN,7,BX,BY,-1N,8,CX,CY,-1N,9,KX,KYTYPE,1REAL,1E,2,3,7E,4,5,8TYPE,2REAL,2E,1,2E,3,4E,5,6E,3,9E,4,9FINISH!求解/SOLUANTYPE,TRANSNLGEOM,ONDELTIM,T/100KBC,0TIME,TOUTRES,BASIC,ALLAUTOTS,ONCNVTOL,F,1,0.1CNVTOL,M,1,0.1 D,ALL,UZD,ALL,ROTXD,ALL,ROTYD,1,ROTZ,2*PI-0.001D,1,UXD,1,UY D,6,UXD,6,UY SOLVE SAVEFINISH!提取数据/POST26*DIM,X_OBJ,ARRAY,10*DIM,Y_OBJ,ARRAY,10X_OBJ(1)=9.5Y_OBJ(1)=8.26X_OBJ(2)=9Y_OBJ(2)=8.87X_OBJ(3)=7.97Y_OBJ(3)=9.51X_OBJ(4)=5.65Y_OBJ(4)=9.94X_OBJ(5)=4.36Y_OBJ(5)=9.7X_OBJ(6)=3.24Y_OBJ(6)=9X_OBJ(7)=3.26Y_OBJ(7)=8.36X_OBJ(8)=4.79Y_OBJ(8)=8.11X_OBJ(9)=6.58Y_OBJ(9)=8X_OBJ(10)=9.12Y_OBJ(10)=7.89X_OBJ_MIN=3.24X_OBJ_MAX=9.5NSOL,2,9,UXNSOL,3,9,UY*DIM,X9,ARRAY,100*DIM,Y9,ARRAY,100VGET,X9,2VGET,Y9,3*DO,I,1,100 X9(I)=KX+X9(I)Y9(I)=KY+Y9(I)*ENDDOG2=B+C-A-D G3=C+D-A-BG4=B+D-A-CCOS_GAMA1=(B*B+C*C-(D-A)*(D-A)/2/B/CCOS_GAMA2=(B*B+C*C-(D+A)*(D+A)/2/B/C*IF,COS_GAMA1,GE,-1,AND,COS_GAMA1,LE,1,THEN G5=ACOS(COS_GAMA1)-30*PI/180*ELSE G5=-1*ENDIF*IF,COS_GAMA2,GE,-1,AND,COS_GAMA2,LE,1,THENG6=150*PI/180-ACOS(COS_GAMA2)*ELSEG6=-1*ENDIFF2=0*DO,I,1,10 F2=F2+(Y9(I*10)-Y_OBJ(I)*(Y9(I*10)-Y_OBJ(I)+(X9(I*10)-X_OBJ(I)*(X9(I*10)-X_OBJ(I)*ENDDOFINISH2. 优化控制文件!File：EXAMPLE27_OPT.TXT/OPTOPCLR FINISH !/CLEAR/INPUT, EXAMPLE27,LGW/OPTOPANL, EXAMPLE27,LGW OPVAR,A,DV,0.1,10,0.001 OPVAR,B,DV,0.1,10,0.001OPVAR,C,DV,0.1,10,0.001OPVAR,D,DV,0.1,10,0.001OPVAR,AX,DV,0.1,5,0.001OPVAR,AY,DV,0.1,5,0.001OPVAR,BATA_OPT,DV,0.1,PI,0.001OPV