implicit and explicit for dynamic analysis

Submitted by kajalschopra on Thu, 09/08/2011 - 23:52

Can anyone please explain the difference between implicit and explicit method with regard to dynamic analysis?

I mean the procedurres to determine the response where in the equations of mottion are uncoupled or non linear dyn amic analysis is to be carried out?

Central difference is an explicit and neumann methos is an implicit method.

It was beautifully explained by Prof.Louis for sttaic non linear analysis in an earlier post and touched by Peymann too for dynamic analysis.A detailed explanation will eb very useful.

Please help

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cjfUNSW

Things needs to know when using UMAT to do dynamic analysis?

Hi, everyone,

Does anyone have some experience on using UMAT to do dynamic analysis? Please give me some help on the problems i encountered.

Currently, I have developed an UMAT and it was successfully applied in the static analysis. The umat was developed for analysing composite laminates, it was for 2D problems, I successfully applied the umat to analysis a plate with hole and subjected to in-plane tension. I applied displacement control method to add the load. However, when I applied it to do dynamic analysis. The simulation method is the same when I did the static analysis. I only change the step into to dynamic implicit step, Unexpected results was obtained. The results I get was only the row of elements applying displacement have the deformations and stresses, other rows remain zero stress and zero displacement.

When I applied it to do the frequency extraction, I even get a error message from abaqus. The error message is as follow:

ERROR in job messaging system: Error in connection to analysis
Error in job plate_freq: The executable C:\SIMULIA\Abaqus\6.9-EF1\exec\standard.exe aborted with system error code 5. Please check the .dat, .msg, and .sta files for error messages if the files exist. If there are no error messages and you cannot resolve the problem, please run the command "abaqus job=support information=support" to report and save your system information. Use the same command to run Abaqus that you used when the problem occurred. Please contact your local Abaqus support office and send them the input file, the file support.log which you just created, the executable name, and the error code.
Job plate_freq aborted due to errors.

I am not so familiar with the dynamic analysis and not knowing how to track the error. Could you please tell me something I have to pay attention to when doing a dynamic analysis linking umat. And could you please also recommend me some reference books or articles on umat and dynamic analysis so that I can refer to.

Your help is greatly appreciated.

Many thanks in advance.

Best regards,
Jingfen