关于生死单元模拟激光融覆的问题讨论
在使用生死单元进行激光熔覆的模拟时关于生死单元的使用始终有些疑问。想将整个熔覆层的单元杀死，然后激光移动到该单元时，该单元激活参与求解，这样求解域就不断增大，但是在进行后处理时，还没激活的单元一开始就参与了运算，这是怎么回事？？？如图所示，查看温度场时，死的单元也有温度？？？在查看时间历程曲线时，如A点，从零秒开始温度就开始变化，这和实际是不符合的？？？？各位，在使用生死单元时是怎么一回事？？？？在开始设置时没有将单元杀死，还是杀死单元的条件不满足？？？ 本帖最后由 521majie 于 2014-7-4 10:18 编辑
77098009 发表于 2014-7-3 16:44
在开始设置时没有将单元杀死，还是杀死单元的条件不满足？？？
开始时将所有熔覆层的单元杀死，然后随着激光移动，激活单元。还有做完热分析后，转换成热应力分析时，总是提示错误；One or more elements have become highly distorted. Excessivedistortion of elements is usually a symptom indicating the need forcorrective action elsewhere. Try incrementing the load more slowly (increase the number of substeps or decrease the time step size). You may need to improve your mesh to obtain elements with better aspect ratios. Also consider the behavior of materials, contact pairs, and/or constraint equations. If this message appears in the first iteration of first substep, be sure to perform element shape checking.然后我将网格划分的很细了，时间步长也很短，但还是出现这个问题？？？？？？您有好的建议么？？
我也被这个问题困扰了很久，求大神解答。为什么明明杀死的单元还会参与运算呢？ 是做的那种焊接方式? 没有完全杀死，还有一定刚度。可以乘以个更小的数，如ESTIF,1e-056 还有，楼主咱探讨一下。我用2D模型，先把焊缝区建成40个面，然后全部杀死（按单元格杀死的），激活时一个一个面激活（按次序激活一个面中的包含的单元）。不知道你会不会杀死激活一个面么 小七工作室 发表于 2014-8-13 16:47
是做的那种焊接方式?
3d打印进行堆焊，你们能做吗？？？ 遥远的土地 发表于 2014-8-21 09:48
还有，楼主咱探讨一下。我用2D模型，先把焊缝区建成40个面，然后全部杀死（按单元格杀死的），激活时一个一 ...
我发了好几个帖子，你可以看一下，里面附有命令流 *** WARNING *** CP = 204.096 TIME= 11:28:33
There are 28 small equation solver pivot terms.This may be a
transitional effect caused by the Newton-Raphson logic.
*** WARNING *** CP = 213.877 TIME= 11:28:39
The ETCHG command has changed some element types.Please examine not
only the KEYOPTs, but also the real constants, material properties,
boundary conditions, and loadings, and then modify as needed.
*** WARNING *** CP = 219.681 TIME= 11:28:44
There are 2312 small equation solver pivot terms.
*** ERROR *** CP = 219.868 TIME= 11:28:44
One or more elements have become highly distorted.Excessive
distortion of elements is usually a symptom indicating the need for
corrective action elsewhere.Try ramping the load up instead of step
applying the load (KBC,1).You may need to improve your mesh to
obtain elements with better aspect ratios.Also consider the behavior
of materials, contact pairs, and/or constraint equations.If this
message appears in the first iteration of first substep, be sure to
run shape checking of elements. 遥远的土地 发表于 2014-9-11 15:57
*** WARNING *** CP = 204.096 TIME= 11:28:33
There are 28 small equat ...
我也遇到这种问题了，楼主怎么解决的 还没有解决啊
都想换个软件了 现在我也有这个问题
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