混凝土非线性分析-应力应变曲线输出

各位同学，这里几乎已经是最完整的命令流了，关于这方面工作，初步建议如下：（1）初步的模拟最好先不要考虑混凝土下降段，不要考虑混凝土的压碎，同时单元尺寸不要过小，以免影响收敛。（2）反复试算结果表明，混凝土的MISO和KINH模型、DP和MISES准则、剪力传递系数对模拟结果影响均不大，但在一定程度上影响了收敛性的好坏。（3）当解决了收敛问题之后，最大的难点是下降段，对于一个桥墩（柱）的反复荷载试验，引起承载力下降的原因大体可归结为：塑性铰区混凝土压碎脱落、纵筋屈曲，对于以剪切破坏为主的试件，还包括剪切滑移的影响。对于以黏结破坏为主的试件，还包括纵筋－混凝土黏结滑移破坏。因此，能否正确模拟这些将是模型正确与否的关键。众所周知，以link8单元模拟钢筋自然无法模拟纵筋屈曲，这样就把一个因素忽略了。（4）作者们最后采用了扩大的破坏面，坦率的讲，这也是为了模拟混凝土的压碎破坏而采取的没有办法的办法，鉴于作者水平有限，至今也无法对此做出更为合理的解释。破坏面到底扩大多少，仍无规律可循。且一旦打开压碎开关，会出现诸如难以收敛、“假压碎”等一系列问题。所以我们建议大家起初还是先不要考虑压碎为好。定义应力应变曲线1，定义变量：拾取主菜单：MainMenu>TimeHistpostproc>DefineVariables>在随之弹出的对话框中点击Add键，定义第一个变量序号为2，选取第一个变量stress,确定与之对应的下一级选项（如Y-directionSY等）；返回定义变量对话框，再点击add键，定义第二个变量序号为3，选取第二个变量strain-elastic及以及对赢得下一级选项（如Y-dir'nEPELY等，在应力-应变图中，其向量的取向应相同）。同理再定义变量4，选取变量strain-plastic及与之对应的下一级选项如Y-dir'nEPELY等），在应力-应变图中，应变是弹性应变和塑性应变累加的总应变。为使其实现相加，还需进行以下操作：拾取主菜单：MainMenu>TimeHistpostproc>mathoperation>add,定义计算变量序号为5，同时在相应交互框内输入3和4。点击确认键，则由变量3，4代表的应变之和就存在变量5中。2，绘制应力-应变曲线：拾取主菜单：MainMenu>TimeHistpostproc>setting>graph.设置x轴向变量为单变量，并将其变量序号定义为5。点击确定键退出退化框。拾取应用菜单：UtilityMenu>plotctrls>styles>Graphs>Modifyaxis.将x,y坐标轴分别命名为Y-strains,Y-stress,拾取主菜单：MainMenu>TimeHistpostproc>graphvariables.在对话框上thefirstvariable对应的交互框中输入2。点击确定键，则预想的应力-应变曲线就显示在屏幕上。ok!试试看！欢迎大家继续批评指正！/prep7et,1,solid65et,2,link8et,3,solid45r,1r,2,236e-6r,3,75.4e-6r,4,151.2e-6!混凝土本构关系mp,ex,1,2.522e10mp,prxy,1,0.2mp,dens,1,2500tb,concr,1,1tbdata,,0.5,0.95,5e6,-1tb,miso,1,1,7tbtemp,0tbpt,,0.00068,17.15e6tbpt,,0.00136,28.03e6tbpt,,0.00204,33.62e6tbpt,,0.00272,35.96e6tbpt,,0.0034,36.53e6tbpt,,0.00408,36.53e6!纵筋的本构关系mp,ex,2,2.0e11mp,prxy,2,0.28tb,bkin,2tbtemp,0tbdata,,362e6,2e9！箍筋的本构关系mp,EX,3,2.1E11mp,PRXY,3,.27tb,bkin,3tbtemp,0tbdata,,272.5e6,2.1e9!建立模型local,11,1,0,0,0,0,-90,0！建立局部坐标系，采用柱坐标，绕y轴顺时针转90度csys,11*do,j,1,8n,j,0.185,j*360/8,-0.6*enddongen,3,100,1,8,1,0,0,0.3！复制节点，3次，编号增量，源节点1~8，0,0,0.3ngen,4,100,201,208,1,0,0,0.15ngen,7,100,501,508,1,0,0,0.3type,2！指定单元属性，建立基础箍筋单元real,3mat,3*do,i,1,6*do,j,1,7e,(i-1)*100+j,(i-1)*100+j+1*enddoe,(i-1)*100+1,(i-1)*100+8*enddotype,2！建立柱上箍筋单元real,4mat,3*do,i,1,5*do,j,1,7e,(i+5)*100+j,(i+5)*100+j+1*enddoe,(i+5)*100+1,(i+5)*100+8*enddotype,2！建立纵向钢筋real,2mat,2*do,i,1,11*do,j,1,8e,(i-1)*100+j,i*100+j*enddo*enddoallsel,all！合并节点，压缩节点nummrg,allnumcmp,allwpcsys,1,11cylind,0,0.185,-0.6,0,0,360！建立圆柱，内外径i-or，高度z1-z2，起终角度cylind,0,0.185,0,0.45,0,360cylind,0.185,0.3,-0.6,0,0,360cylind,0,0.185,0.45,2.25,0,360cylind,0,0.185,2.25,2.55,0,360cylind,0.185,0.20,2.25,2.55,0,360cylind,0,0.185,2.55,2.565,0,360wprota,,90！绕y轴逆时针转90度vsel,s,,,1,7,1！选择体，选择类型，item，comb，最小编号，最大编号，增量vsbw,all！体相减numcmp,allwprota,,,90！绕z轴逆时针转90度vsel,s,,,1,14,1vsbw,allnumcmp,allvsel,s,,,1,28,1vglue,allnumcmp,allwprota,,,-90wprota,,-90allsel,allvsel,s,,,1,16,1vsel,a,,,21,24,1vatt,1,1,1vsel,s,,,17,20,1vsel,a,,,25,28,1vatt,2,1,3allsel,alllsel,s,,,1,8,1！选择线lsel,a,,,11,22,1！补选（a）线lsel,a,,,25,40,1lsel,a,,,43,46,1lesize,all,,,2！线尺寸为2lsel,s,,,47,50,1lsel,a,,,53,56,1lsel,a,,,58,73,1lesize,all,,,2lsel,s,,,98,107,1lsel,a,,,110,112,2lesize,all,,,1lsel,s,,,23,24,1lsel,a,,,9,10,1lesize,all,,,2lsel,s,,,78,82,1lesize,all,,,3lsel,s,,,83,87,1lesize,all,,,6lsel,s,,,41,42,1lsel,a,,,88,92,1lesize,all,,,2lsel,s,,,93,97,1lesize,all,,,1mshkey,1mshape,0,3dvsel,s,,,1,28vmesh,allallsel,allnummrg,allnumcmp,allwprota,,90csys,0allsel,all/solu！进入加载、求解csys,11nsel,s,loc,x,0.3！选择半径在x=3处的节点，并施加约束d,all,allallsel,allOUTRES,ALL,2！输出获得的解csys,0pred,on！打开预应力选项cnvtol,f,,0.05,2!定义收敛条件,使用缺省的VALUEautots,1!打开自动时间步控制lnsrch,1!打开线性搜索ncnv,2!如果不收敛时结束而不退出neqit,50!每一子步中方程的迭代次数限值savetime,1！定义第1载荷步nsubst,10asel,s,,,29,32,1sfa,all,,pres,5468699！在已选择的面上施加压力荷载allsel,allacel,,9.8！重力加速度y=9.8kbc,1！阶跃加载方式lswrite,1time,10！定义第2荷载步cp,1,ux,298,300,303!将节点298,300,303ux向位移耦合d,298,ux,0.015！再借点298处施加ux位移0.015allsel,allKBC,0allsel,allNSUBST,20,1000000,10lswrite,2time,20！定义第3载荷步d,298,ux,-0.015allsel,allKBC,0allsel,allNSUBST,100,1000000,10lswrite,3time,30！定义第4载荷步d,298,ux,0.015allsel,allKBC,0allsel,allNSUBST,100,1000000,10lswrite,4time,40！定义第5载荷步d,298,ux,-0.015allsel,allKBC,0allsel,allNSUBST,100,1000000,10lswrite,5time,50！定义第6载荷步d,298,ux,0.015allsel,allKBC,0allsel,allNSUBST,100,1000000,10lswrite,6time,60！定义第7载荷步d,298,ux,-0.015allsel,allKBC,0allsel,allNSUBST,100,1000000,10lswrite,7time,70！定义第8载荷步d,298,ux,0.015allsel,allKBC,0allsel,allNSUBST,100,1000000,10lswrite,8time,80d,298,ux,-0.015allsel,allKBC,0allsel,allNSUBST,100,1000000,10lswrite,9time,90d,298,ux,0.015allsel,allKBC,0allsel,allNSUBST,100,1000000,10lswrite,10time,100d,298,ux,-0.015allsel,allKBC,0allsel,allNSUBST,100,1000000,10lswrite,11time,110d,298,ux,0.03allsel,allKBC,0allsel,allNSUBST,200,1000000,10lswrite,12time,120d,298,ux,-0.03allsel,allKBC,0allsel,allNSUBST,200,1000000,10lswrite,13time,130d,298,ux,0.03allsel,allKBC,0allsel,allNSUBST,200,1000000,10lswrite,14time,140d,298,ux,-0.03allsel,allKBC,0allsel,allNSUBST,200,1000000,10lswrite,15time,150d,298,ux,0.03allsel,allKBC,0allsel,allNSUBST,200,1000000,10lswrite,16time,160d,298,ux,-0.03allsel,allKBC,0allsel,allNSUBST,200,1000000,10lsw