問(wèn)題2:當(dāng)使用UMAT子程序是出現(xiàn)以下錯(cuò)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(shè)置了減縮積分,所以出現(xiàn)沙漏現(xiàn)象,將其改成全積分或imcompatible可解決,詳細(xì)解析在《基于ABAQUS的有限元分析和應(yīng)用》的第510頁(yè)。

問(wèn)題3:提交作業(yè)后模型出現(xiàn)問(wèn)題,standard.exe 停止工作,只生成dat文件而沒(méi)有找到msg文件

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

問(wèn)題4:當(dāng)使用UMAT子程序,提交任務(wù)前進(jìn)行Data Check出現(xiàn)以下錯(cuò)誤提示

USER SUBROUTINE IS MISSING

解決辦法:Edit job,設(shè)置子程序xx.for的路徑。曾經(jīng)出現(xiàn)不設(shè)置也能運(yùn)算的情況,但系大部分情況下,不設(shè)置都會(huì)出現(xiàn)上述提示,反正設(shè)置好路徑就不會(huì)錯(cuò)了。

問(wèn)題5:出現(xiàn)收斂問(wèn)題解決辦法很多

1.可能模型本身有問(wèn)題

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

3.如果剛度矩陣是非對(duì)稱,一定要選擇不對(duì)稱,否則按對(duì)稱算,就會(huì)出現(xiàn)問(wèn)題

4.縮小initial 同 maximum 的step size

5.在step設(shè)置時(shí)增加damping

問(wèn)題6: 同時(shí)調(diào)用多個(gè)子程序而job editor只能指定一個(gè)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(wèn)題7:輸出的應(yīng)變應(yīng)力是真實(shí)應(yīng)變應(yīng)力還是名義的應(yīng)變應(yīng)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(jié)果為真實(shí)應(yīng)力(S)和真實(shí)應(yīng)變(E/LE/NE)

另外,要理解好真實(shí)應(yīng)力/應(yīng)變和名義應(yīng)力/應(yīng)變的定義,不是所有的實(shí)驗(yàn)結(jié)果都必定以名義應(yīng)力/應(yīng)變給出,所以輸入數(shù)據(jù)時(shí),分清楚究竟需不需要進(jìn)行轉(zhuǎn)換。一句話,具體情況具體分析!