Displacement increment for contact is too big
關(guān)注創(chuàng)建者：Foreverup 創(chuàng)建時間：2019-03-30
Displacement increment for contact is too big的實例教程
初學(xué)者常常會得到這樣一條經(jīng)驗建議:有些場合可以采用位移控制的方式（displacement-control）來替代力量控制(Load-control)的方式來改善收斂。
在我們的實際案例中，也確實常常會發(fā)現(xiàn)力量加載不收斂，換做位移控制就收斂了，為什么？哪種狀況適合采用使用位移加載代替力量加載的策略來提高收斂的順暢性呢？
請參考如下案例，此例為Abaqus自帶的典型案例分析中一個關(guān)于接觸穩(wěn)定與載荷的平衡問題，10KN的張緊力作用在螺母上（對稱模型的半螺母5KN）來緊固輪轂輪邊：
Figure-1:輪轂輪邊的緊固接觸
初次求解，增量步長減小五次后仍無法求解，分析終止。
從job monitor中查看Message File或從工作目錄下打開相關(guān)job的.msg文件查看提示的Error信息，看到數(shù)值奇異的警告提示：
******************************************
***WARNING: SOLVER PROBLEM. NUMERICAL SINGULARITY WHEN PROCESSING NODE
HALFHUB-1.535 D.O.F. 1 RATIO = 115.819E+12 .
***WARNING: DISPLACEMENT INCREMENT FOR CONTACT IS TOO BIG.
***WARNING: DISPLACEMENT INCREMENT FOR CONTACT IS TOO BIG.
展開 初學(xué)者常常會得到這樣一條經(jīng)驗建議:有些場合可以采用位移控制的方式（displacement-control）來替代力量控制(Load-control)的方式來改善收斂。
在我們的實際案例中，也確實常常會發(fā)現(xiàn)力量加載不收斂，換做位移控制就收斂了，為什么？哪種狀況適合采用使用位移加載代替力量加載的策略來提高收斂的順暢性呢？
請參考如下案例，此例為Abaqus自帶的典型案例分析中一個關(guān)于接觸穩(wěn)定與載荷的平衡問題，10KN的張緊力作用在螺母上（對稱模型的半螺母5KN）來緊固輪轂輪邊：
Figure-1:輪轂輪邊的緊固接觸
初次求解，增量步長減小五次后仍無法求解，分析終止。
從job monitor中查看Message File或從工作目錄下打開相關(guān)job的.msg文件查看提示的Error信息，看到數(shù)值奇異的警告提示：
******************************************
***WARNING: SOLVER PROBLEM. NUMERICAL SINGULARITY WHEN PROCESSING NODE
HALFHUB-1.535 D.O.F. 1 RATIO = 115.819E+12 .
***WARNING: DISPLACEMENT INCREMENT FOR CONTACT IS TOO BIG.
***WARNING: DISPLACEMENT INCREMENT FOR CONTACT IS TOO BIG.
展開 
Displacement increment for contact is too big的相關(guān)專題、標(biāo)簽、搜索
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Displacement increment for contact is too big的最新內(nèi)容
一般類似于：
1）Fixed time is too large；
2）Too many attamps have been made；
3）THE SOLUTION APPEARS TO BE DIVERGING；
4）CONVERGENCE ISJUDGED UNLIKELY；
5）Time increment required is less than the minimum
The motivations are:
to get a more realistic solution, where the neighboring segments do not have too big variation in their Restraining Forces.
***WARNING: DISPLACEMENT INCREMENT FOR CONTACT IS TOO BIG.
***WARNING: DISPLACEMENT INCREMENT FOR CONTACT IS TOO BIG.
***WARNING: DISPLACEMENT INCREMENT FOR CONTACT IS TOO BIG.
***WARNING: DISPLACEMENT INCREMENT FOR CONTACT IS TOO BIG.
BLANK-1.5 IS OVERCLOSED
BY0.0512228 WHICH IS TOO SEVERE
這往往是因為接觸面的法線方向定義反了。
