线性粘弹性UMAT

1、深入剖析UMAT线形粘弹性体liuxiongsimwe用户名：LXCAD摘要本文介绍了线形粘弹体的UMAT程序说明，与ZHANG chunyu一起学习UMAT为姐妹篇。UMAT其实并不难学，你要把握几点即可：1， 必须提供准确的雅可比距阵，程序收敛速度快2， 必须用增量法更新应力· must update the stresses and solution-dependent state variables to their values at the end of the increment for which it is called;· must provide th

2、e material Jacobian matrix3，与本构方程相关的状态变量必须更新把我分析的子程序过程多读几遍，相关的弹性力学，朔性力学概念弄懂，可能就理解更为清晰！我的目的就是让大家学的轻松！请大家鼓励！三单元体的固体模型(线形粘弹性)下图为虎克体和开尔文体的串联一维方向的应力与应变的行为推广到实体其中PROPS(1)PROPS(2)PROPS(3)PROPS(4)PROPS(5)SUBROUTINE UMAT(STRESS,STATEV,DDSDDE,SSE,SPD,SCD, 1 RPL,DDSDDT,DRPLDE,DRPLDT, 2 STRAN,DSTRAN,TIME,DTIME,

3、TEMP,DTEMP,PREDEF,DPRED,CMNAME, 3 NDI,NSHR,NTENS,NSTATV,PROPS,NPROPS,COORDS,DROT,PNEWDT, 4 CELENT,DFGRD0,DFGRD1,NOEL,NPT,LAYER,KSPT,KSTEP,KINC)C INCLUDE 'ABA_PARAM.INC'C CHARACTER*80 CMNAME DIMENSION STRESS(NTENS),STATEV(NSTATV), 1 DDSDDE(NTENS,NTENS), 2 DDSDDT(NTENS),DRPLDE(NTENS), 3 STRAN(

4、NTENS),DSTRAN(NTENS),TIME(2),PREDEF(1),DPRED(1), 4 PROPS(NPROPS),COORDS(3),DROT(3,3),DFGRD0(3,3),DFGRD1(3,3) DIMENSION DSTRES(6),D(3,3)CC EVALUATE NEW STRESS TENSORC EV = 0. DEV = 0. DO K1=1,NDI EV = EV + STRAN(K1) ! 直接应力和 DEV = DEV + DSTRAN(K1) !直接增量应力和 END DOC TERM1 = .5*DTIME + PROPS(5) ! TERM1I

5、= 1./TERM1 ! TERM2 = (.5*DTIME*PROPS(1)+PROPS(3)*TERM1I*DEV ! TERM3 = (DTIME*PROPS(2)+2.*PROPS(4)*TERM1I ! C更新正应力 DO K1=1,NDI DSTRES(K1) = TERM2+TERM3*DSTRAN(K1) 1 +DTIME*TERM1I*(PROPS(1)*EV2 +2.*PROPS(2)*STRAN(K1)-STRESS(K1)本构方程程序执行：+ STRESS(K1) = STRESS(K1) + DSTRES(K1) END DOC 更新剪应力TERM2= TERM2 =

6、 (.5*DTIME*PROPS(2) + PROPS(4)*TERM1I I1 = NDI DO K1=1,NSHR I1 = I1+1本构方程程序执行：*+* DSTRES(I1) = TERM2*DSTRAN(I1)+ 1 DTIME*TERM1I*(PROPS(2)*STRAN(I1)-STRESS(I1) STRESS(I1) = STRESS(I1)+DSTRES(I1) END DOC雅可比距阵开始C CREATE NEW JACOBIANCTERM2=* TERM2 = (DTIME*(.5*PROPS(1)+PROPS(2)+PROPS(3)+ 1 2.*PROPS(4)*T

7、ERM1I TERM3 =*TERM3 = (.5*DTIME*PROPS(1)+PROPS(3)*TERM1I DO K1=1,NTENS DO K2=1,NTENS DDSDDE(K2,K1) = 0. END DO END DOC DO K1=1,NDI DDSDDE(K1,K1) = TERM2 END DOC填充距阵如下位置 DO K1=2,NDI N2 = K11 DO K2=1,N2 DDSDDE(K2,K1) = TERM3 DDSDDE(K1,K2) = TERM3 END DOEND DOTERM2 =* TERM2 = (.5*DTIME*PROPS(2)+PROPS(4

8、)*TERM1II1 = NDI !l1=3按新TERM2填充距阵如下位置 DO K1=1,NSHR !按剪切力运行3次 I1 = I1+1 DDSDDE(I1,I1) = TERM2END DO小结：雅可比距阵填充完毕C关于物质能量的增长C TOTAL CHANGE IN SPECIFIC ENERGYC TDE = 0. DO K1=1,NTENS TDE = TDE + (STRESS(K1)+.5*DSTRES(K1)*DSTRAN(K1) END DOC C关于朔性能量的增长C CHANGE IN SPECIFIC ELASTIC STRAIN ENERGYCTERM1 = PROP

9、S(1) + 2.*PROPS(2) !TERM1=填充距阵如下位置 DO K1=1,NDI D(K1,K1) = TERM1END DO填充距阵如下位置 DO K1=2,NDI N2 = K1-1 DO K2=1,N2 D(K1,K2) = PROPS(1) D(K2,K1) = PROPS(1) END DOEND DO直接应力部分外循环数内循环数K1K2TERM1TERM2DEE1111212+313+2121222+323+3131232+333+分析以下循环，实质为能量变化，力*位移 DEE = 0. DO K1=1,NDI TERM1 = 0. TERM2 = 0. DO K2=1,NDI TERM1 = TERM1 + D(K1,K2)*STRAN(K2) TERM2 = TERM2 + D(K1,K2)*DSTRAN(K2) END DO DEE = DEE + (TERM1+.5*TERM2)*DSTRAN(K1) END DO 剪切应力部分L1K1DDE415263I1 = NDI DO K1=1,NSHR I1 = I1+1 DEE = DEE +