求助：计算结果有很多的警告，而且不收敛，请求大师们指点迷津~多谢!

goldenflower

求助：计算结果有很多的警告，而且不收敛，请大师们帮我看看，实在是没有头绪。。
以下是out文件：
INITIAL TIME..................................... =  0.00000000E+00
     TIME STEP LENGTH................................. =  0.10000000E+01
     TIME STEP........................................ =            1
     -------------------------------------------------------------------------------------------------------------------------------
     EQUILIBRIUM   RELATIVE RESIDUALS OF          MAXIMUM DISPLACEMENT          MAXIMUM STRESS                SOLUTION TIMES
     ITERATION     DISPLACEMENT    STRESS       SOLID NODE     MAGNITUDE   SOLID NODE     MAGNITUDE      SOLID MODEL   FLUID MODEL
     -------------------------------------------------------------------------------------------------------------------------------

*** WARNING *** CODE ADF6033:

    Absolute residual 9.87E+20 of pressure is too large.


*** WARNING *** CODE ADF6033:

    Absolute residual 2.92E+26 of pressure is too large.


*** WARNING *** CODE ADF6033:

    Absolute residual 1.21E+25 of velocity is too large.


*** WARNING *** CODE ADF6033:

    Absolute residual 1.78E+39 of pressure is too large.


*** WARNING *** CODE ADF6065:

    Fluid model could be unstable! The factorized diagonal 5.8131E-23 of
    equation 43216 is too small.


*** WARNING *** CODE ADF6065:

    Fluid model could be unstable! The factorized diagonal 3.2486E-23 of
    equation 43212 is too small.


*** WARNING *** CODE ADF6065:

    Fluid model could be unstable! The factorized diagonal 1.8380E-23 of
    equation 47208 is too small.


*** WARNING *** CODE ADF6065:

    Fluid model could be unstable! The factorized diagonal 1.3774E-23 of
    equation 47188 is too small.


*** WARNING *** CODE ADF6065:

    Fluid model could be unstable! The factorized diagonal 4.5143E-23 of
    equation 49868 is too small.


*** WARNING *** CODE ADF6065:

    Fluid model could be unstable! The factorized diagonal 1.6071E-23 of
    equation 43884 is too small.


*** WARNING *** CODE ADF6065:

    Fluid model could be unstable! The factorized diagonal 7.3692E-23 of
    equation 49852 is too small.


*** WARNING *** CODE ADF6065:

    Fluid model could be unstable! The factorized diagonal 1.9354E-23 of
    equation 47184 is too small.


*** WARNING *** CODE ADF6065:

    Fluid model could be unstable! The factorized diagonal 5.6300E-23 of
    equation 46580 is too small.

    Too many error/warning messages for code number ADF6065 have been
    encountered.

*** WARNING *** CODE ADF6064:

    Fluid model could be wrong! The factorized diagonal 8.0155E-26 of
    equation 32692 is too small.
    A constant pivot has been assigned to this equation.


*** WARNING *** CODE ADF6064:

    Fluid model could be wrong! The factorized diagonal -8.346E-26 of
    equation 46016 is too small.
    A constant pivot has been assigned to this equation.


*** WARNING *** CODE ADF6064:

    Fluid model could be wrong! The factorized diagonal 4.8758E-26 of
    equation 45812 is too small.
    A constant pivot has been assigned to this equation.


*** WARNING *** CODE ADF6064:

    Fluid model could be wrong! The factorized diagonal -1.024E-26 of
    equation 45496 is too small.
    A constant pivot has been assigned to this equation.


*** WARNING *** CODE ADF6064:

    Fluid model could be wrong! The factorized diagonal 8.4784E-26 of
    equation 45628 is too small.
    A constant pivot has been assigned to this equation.


*** WARNING *** CODE ADF6064:

    Fluid model could be wrong! The factorized diagonal 4.8879E-26 of
    equation 71480 is too small.
    A constant pivot has been assigned to this equation.


*** WARNING *** CODE ADF6064:

    Fluid model could be wrong! The factorized diagonal 7.1049E-26 of
    equation 99052 is too small.
    A constant pivot has been assigned to this equation.


*** WARNING *** CODE ADF6064:

    Fluid model could be wrong! The factorized diagonal 7.9305E-26 of
    equation 92220 is too small.
    A constant pivot has been assigned to this equation.


*** WARNING *** CODE ADF6064:

    Fluid model could be wrong! The factorized diagonal 6.9135E-26 of
    equation 75840 is too small.
    A constant pivot has been assigned to this equation.

    Too many error/warning messages for code number ADF6064 have been
    encountered.
*** ERROR *** CODE ADF2005:

    Iteration limit is reached without convergence.
    Equilibrium is not established from time: 0.00000E+00
                                     to time: 1.00000E+00
请大师们指点迷津，改过网格，改过时间步，都没啥成效，都不知道该怎么下手了。。
我把in文件也传上来吧，请大师们帮我看看是什么问题，一定要帮忙~着急~
我知道自己是新手，甚至还没入门，但我怎么觉得ADINA这么难用呢？学习这个软件有什么技巧吗？请大师们不吝赐教，小弟先谢过了！

goldenflower

哎。。。。。。。。。。

denglong

高手希望回答下 我也有这样的问题

zzteng

求助：计算结果有很多的警告，而且不收敛，请大师们帮我看看，实在是没有头绪。。
以下是out文件：
INITIAL TIME..................................... =  0.00000000E+00
     TIME STEP LENGTH............... ...
goldenflower 发表于 2010-12-15 15:26

出现这样的问题, 一般是流体部分的mesh有问题.
1. 首先你应该把你的问题描述一下.
2. 你的time step只有一步
3. 你的上下2个细长边是什么边界条件?
4. 自动生成的mesh(流体部分)里头肯定有非常不好的网格.
5. 你这个结构, 完全可以进一步剖分一下, 后生成结构化网格. 例如, 在固体部分内部加8个点, 把它(剖面)变成铜钱样结构, 这样就可以生成6面体网格; 流体部分的圆孔部分可以类似处理; 突出的部分可以用三棱镜的体划分.

goldenflower

4# zzteng
这个问题是模拟河道水流对桥墩的作用，由于桥墩周围河床被冲刷形成一个坑，所以流体呈不规则形，初始条件是水流速度，桥墩为圆柱体，材料为混凝土。我分别建好结构模型和流体模型，保存好dat文件，然后在高性能计算机上进行FSI运算。
1. 我设置的是自动时间步。请问自动时间步什么时候设置才能有效？
2.上边界为自由液面边界，下边界为WALL边界。
3.划分网格方面我不太懂，您说的那种划分网格方法该如何实现呢？我这个是用ADINA-M建的模型，因为形状不规则，进行布尔运算建模方便一些。您能给一些用NATIVE方式建不规则形状模型的方法吗？
多谢指教！

zzteng

5# goldenflower

我手画了张示意图. (A) 是流体剖面的划分; (B) 是固体剖面的划分; (C) 是不规则棱镜之一, 以组成坑(4个棱镜组成一个坑). 绿色的点就是你要另外加的数据点, 用直线连接上下两个面之间对应的绿色点. 这样就把整个流体分成小体, 再规定每个小体的(u,v,w)就可以生成网格了.

nickcoom

楼主的模型，基本就是，圆柱，圆台，长方体的组合，如何下刀切割，这得看lz的刀法了，楼主在6#的提示下应该有帮助了，但是个人觉得，在cad里面直接做好分块导入，是不是方便点呢，我测试过几次，效果不错，

goldenflower

6# zzteng
您真是太细心了，多谢多谢！

goldenflower

7# nickcoom
您能详细说下用CAD做分块导入的做法吗？谢谢啦~

goldenflower

6# zzteng
您说的这种做法，需要用到section sheet吗？

zzteng

6# zzteng  
您说的这种做法，需要用到section sheet吗？
goldenflower 发表于 2010-12-20 15:32

我喜欢在Matlab里头弄点, 线, 面和体.
你可以看 http://forum.simwe.com/viewthread.php?tid=962066&page=1#pid2257871
(4 楼) 我具体解释了定义这些几何的命令格式.

nwcwww

逮到老滕。

zzteng

逮到老滕。
nwcwww 发表于 2011-1-4 00:32

难道你是我隔壁的?
改天布置几道FSI整整. :p