ERROR: FIXED TIME INCREMENT IS TOO LARGE

laoyao239

我做单桩和土的地应力平衡可以成功，但是多加了一个桩就算不下去了，提示 ERROR: FIXED TIME INCREMENT IS TOO LARGE。

警告信息：

THE SLAVE SURFACES _PICKEDSURF8 AND _PICKEDSURF31 INTERSECT EACH OTHER. THEY
ARE PAIRED WITH MASTER SURFACES _PICKEDSURF7 AND _PICKEDSURF30 THAT ALSO
INTERSECT EACH OTHER. IF BOTH PAIRS ARE *CONTACT PAIRs, THESE TWO PAIRS
SHOULD NOT BE SIMULTANEOUSLY PRESENT IN A STEP BECAUSE OF POSSIBLE
CONVERGENCE PROBLEMS; USE *MODEL CHANGE,TYPE=CONTACT PAIR TO REMOVE ONE OF
THEM. IF BOTH ARE *TIE PAIRS, THE REDUNDANT TIES WILL BE REMOVED
AUTOMATICALLY. IF ONE PAIR IS *TIE AND ANOTHER IS *CONTACT PAIR, REMOVE ONE
OF THEM.

THE SLAVE SURFACES _PICKEDSURF10 AND _PICKEDSURF31 INTERSECT EACH OTHER. THEY
ARE PAIRED WITH MASTER SURFACES _PICKEDSURF9 AND _PICKEDSURF30 THAT ALSO
INTERSECT EACH OTHER. IF BOTH PAIRS ARE *CONTACT PAIRs, THESE TWO PAIRS
SHOULD NOT BE SIMULTANEOUSLY PRESENT IN A STEP BECAUSE OF POSSIBLE
CONVERGENCE PROBLEMS; USE *MODEL CHANGE,TYPE=CONTACT PAIR TO REMOVE ONE OF
THEM. IF BOTH ARE *TIE PAIRS, THE REDUNDANT TIES WILL BE REMOVED
AUTOMATICALLY. IF ONE PAIR IS *TIE AND ANOTHER IS *CONTACT PAIR, REMOVE ONE
OF THEM.

THE SLAVE SURFACES _PICKEDSURF12 AND _PICKEDSURF33 INTERSECT EACH OTHER. THEY
ARE PAIRED WITH MASTER SURFACES _PICKEDSURF11 AND _PICKEDSURF32 THAT ALSO
INTERSECT EACH OTHER. IF BOTH PAIRS ARE *CONTACT PAIRs, THESE TWO PAIRS
SHOULD NOT BE SIMULTANEOUSLY PRESENT IN A STEP BECAUSE OF POSSIBLE
CONVERGENCE PROBLEMS; USE *MODEL CHANGE,TYPE=CONTACT PAIR TO REMOVE ONE OF
THEM. IF BOTH ARE *TIE PAIRS, THE REDUNDANT TIES WILL BE REMOVED
AUTOMATICALLY. IF ONE PAIR IS *TIE AND ANOTHER IS *CONTACT PAIR, REMOVE ONE
OF THEM.

THE SLAVE SURFACES _PICKEDSURF14 AND _PICKEDSURF33 INTERSECT EACH OTHER. THEY
ARE PAIRED WITH MASTER SURFACES _PICKEDSURF13 AND _PICKEDSURF32 THAT ALSO
INTERSECT EACH OTHER. IF BOTH PAIRS ARE *CONTACT PAIRs, THESE TWO PAIRS
SHOULD NOT BE SIMULTANEOUSLY PRESENT IN A STEP BECAUSE OF POSSIBLE
CONVERGENCE PROBLEMS; USE *MODEL CHANGE,TYPE=CONTACT PAIR TO REMOVE ONE OF
THEM. IF BOTH ARE *TIE PAIRS, THE REDUNDANT TIES WILL BE REMOVED
AUTOMATICALLY. IF ONE PAIR IS *TIE AND ANOTHER IS *CONTACT PAIR, REMOVE ONE
OF THEM.

For *tie pair (_pickedsurf31-_pickedsurf30), adjusted nodes with very small
adjustments were not printed. Specify *preprint,model=yes for complete
printout.

For *tie pair (_pickedsurf33-_pickedsurf32), adjusted nodes with very small
adjustments were not printed. Specify *preprint,model=yes for complete
printout.

同样的接触设置方法，一个桩就成功了，多了一个桩就这么多错误，到底是什么原因？我查遍资料也没个介绍这个问题的！论坛上有不少朋友遇到过这个问题，好象也没有系统解决办法？有大侠指点下吗？

jaywyan

我的也是啊，换个材料什么的就说增量太大，完全没办法。
不过我的出错提示是：
ELEMENTS ARE DISTORTING EXCESSIVELY. CONVERGENCE IS JUDGED UNLIKELY.
SEVERE CONTACT OVERCLOSURES EXIST. CONVERGENCE IS JUDGED UNLIKELY.

laoyao239

心急如焚啊！

cdstudio

一万年以前, 土就是这样的, 里面是没有桩的, 人们也是不知道什么叫桩的, 土里的应力一直存在的, 地表位移到你想把桩插入土体里面之前, 一直都为0, 为了得到这样一种存在地应力但地表位移为0的状态, 我们使用了一种方法叫地应力平衡.

zgustc

赞楼上

laoyao239

4楼的大哥啊，你的理解太深刻了！我的课题就是复合地基啊，怎么办啊，碰上这种事情，我知道你是高手，你能告诉我吗？是不是没办法解决啊？要吐血了！

jaywyan

原帖由 cdstudio 于 2008-11-20 17:24 发表
一万年以前, 土就是这样的, 里面是没有桩的, 人们也是不知道什么叫桩的, 土里的应力一直存在的, 地表位移到你想把桩插入土体里面之前, 一直都为0, 为了得到这样一种存在地应力但地表位移为0的状态, 我们使用了一种方 ...

关于地应力平衡我一直有点不了解。平衡应力就相当于反作用力吧，平衡后地应力与重力刚好抵消，使位移为零。
真实情况下，如果施加一个上拉荷载，地应力会降低，其与重力的差值与荷载平衡。abaqus里面平衡后加上拉力，地应力会减小吗？否则与荷载平衡的力是怎么出来的？出了变形的作用力，重力还起作用吗？

laoyao239

哈哈，问题解决了！我用轴对称建模算单桩，可以平衡，两个桩就不平衡了，结果我不用轴对称，两个桩的也平衡了，看来应该是这样的，群桩复合地基的地应力平衡不能用轴对称！

再次感谢各位朋友的热心帮忙！

tot-fq

你好，我也做的2根桩的，用2维的能做吗？我老是计算出错，没法计算下去，请问楼主有实例没，可以发到我邮箱totfangqian@gmail.com，学习学习，不甚感激！

888ysq6

楼主啊，小弟是初学者，也要做桩基础的模拟，楼主有没有这方面的实例啊，也给小弟发一个
888ysq6@163.com       感激不尽！！

peidawei

cdstudio 就是强啊，狂顶

zhousonghrbeu

问下楼主，你的例子中“THE SLAVE SURFACES _PICKEDSURF10 AND _PICKEDSURF31 INTERSECT EACH OTHER”对于最终计算有影响吗？