問題2:當使用UMAT子程序是出現以下錯誤

Error in job Job-line44: 630 elements have been defined with zero hour glass stiffness. You may use *hourglass stiffness or change the element type. The elements have been identified in element set ErrElemZeroHourGlassStiffness.

解決辦法:由于設置了減縮積分,所以出現沙漏現象,將其改成全積分或imcompatible可解決,詳細解析在《基于ABAQUS的有限元分析和應用》的第510頁。

問題3:提交作業后模型出現問題,standard.exe 停止工作,只生成dat文件而沒有找到msg文件

解決辦法:黃色圖標的文件即msg文件,但文件類型顯示為outlook,用記事本打開即可。

問題4:當使用UMAT子程序,提交任務前進行Data Check出現以下錯誤提示

USER SUBROUTINE IS MISSING

解決辦法:Edit job,設置子程序xx.for的路徑。曾經出現不設置也能運算的情況,但系大部分情況下,不設置都會出現上述提示,反正設置好路徑就不會錯了。

問題5:出現收斂問題解決辦法很多

1.可能模型本身有問題

2.更改tolerance,在step-->other-->general solution control(慎用)

3.如果剛度矩陣是非對稱,一定要選擇不對稱,否則按對稱算,就會出現問題

4.縮小initial 同 maximum 的step size

5.在step設置時增加damping

問題6: 同時調用多個子程序而job editor只能指定一個路徑

You can specify only one user subroutine file in the job editor; if your analysis involves more than one user subroutine, you must combine the user subroutines into one file and then specify that file.

問題7:輸出的應變應力是真實應變應力還是名義的應變應力?

The stress measure used in Abaqus is Cauchy or “true” stress, which corresponds to the force per current area.For geometrically nonlinear analysis, a large number of different strain measures exist. Unlike “true” stress, there is no clearly preferred “true” strain. For the same physical deformation different strain measures will report different values in large-strain analysis. The optimal choice of strain measure depends on analysis type, material behavior, and (to some degree) personal preference.

By default, the strain output in Abaqus/Standard is the “integrated” total strain (output variable E). For large-strain shells, membranes, and solid elements in Abaqus/Standard two other measures of total strain can be requested: logarithmic strain (output variable LE) and nominal strain (output variable NE).

Logarithmic strain (output variable LE) is the default strain output in Abaqus/Explicit; nominal strain (output variable NE) can be requested as well. The “integrated” total strain is not available in Abaqus/Explicit.

因此,缺省情況下,輸出結果為真實應力(S)和真實應變(E/LE/NE)

另外,要理解好真實應力/應變和名義應力/應變的定義,不是所有的實驗結果都必定以名義應力/應變給出,所以輸入數據時,分清楚究竟需不需要進行轉換。一句話,具體情況具體分析!