问题2:当使用UMAT子程序是出现以下错误

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.

解决办法:由于设置了减缩积分,所以出现沙漏现象,将其改成全积分或imcompatible可解决,详细解析在《基于ABAQUS的有限元分析和应用》的第510页。

问题3:提交作业后模型出现问题,standard.exe 停止工作,只生成dat文件而没有找到msg文件

解决办法:黄色图标的文件即msg文件,但文件类型显示为outlook,用记事本打开即可。

问题4:当使用UMAT子程序,提交任务前进行Data Check出现以下错误提示

USER SUBROUTINE IS MISSING

解决办法:Edit job,设置子程序xx.for的路径。曾经出现不设置也能运算的情况,但系大部分情况下,不设置都会出现上述提示,反正设置好路径就不会错了。

问题5:出现收敛问题解决办法很多

1.可能模型本身有问题

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

3.如果刚度矩阵是非对称,一定要选择不对称,否则按对称算,就会出现问题

4.缩小initial 同 maximum 的step size

5.在step设置时增加damping

问题6: 同时调用多个子程序而job editor只能指定一个路径

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.

问题7:输出的应变应力是真实应变应力还是名义的应变应力?

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,缺省情况下,输出结果为真实应力(S)和真实应变(E/LE/NE)

另外,要理解好真实应力/应变和名义应力/应变的定义,不是所有的实验结果都必定以名义应力/应变给出,所以输入数据时,分清楚究竟需不需要进行转换。一句话,具体情况具体分析!