modeling friction stir welding using transient structural workbench

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Kremella posted this 27 April 2020

Hello all,

I am modeling friction stir welding using transient structural WB. I keep getting the following errors:

1. Some of the element based thermal loads may be inappropriate. Check applied element loads carefully.  Ensure those film coefficients and bulk temperatures are always positive.

2. Element 232 (type = 5, SOLID226) (and maybe other elements) has become highly distorted.  Excessive distortion of elements is usually a symptom indicating the need for corrective action elsewhere.  Try ramping the load up instead of step applying the load (KBC,1).  You may need to improve your mesh to obtain elements with better aspect ratios.  Also consider the behavior of materials, contact pairs, and/or constraint equations.  Please rule out other root causes of  this failure before attempting rezoning or nonlinear adaptive solutions.  If this message appears in the first iteration of first substep, be sure to run shape checking of elements.

BTW: I followed most recommendations that are available on student-community, unfortunately, didn't solve those issues. Any hints or suggestions are available to me. Thank you in advanced,

best, 

Omar

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Wenlong posted this 27 April 2020

Hi Omar,

Have you checked this Tech demonstration guide: https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v193/ans_tec/tecfricstir.html? It may give you some ideas. 

Regards,

Wenlong

 

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Aniket posted this 28 April 2020

 Omar, also putting this here which I already communicated to you for community:

 

can you please check if you are following guideline help you:

For transient thermal:

Please check if you are seeing any thermal undershoot, meaning temperatures below ambient in your model. In case yes, please check guidelines here to avoid that:

3.4.3.2. General Options

https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v195/ans_the/Hlp_G_THE3_5.html%23aPpQxq1d0mcm

by ensuring your minimum time step size follows this equation as explained in the help above:

ITS = Δ^2 / 4 α

 

once you have ensured that and there is no thermal undershoot, please check if you see the same error in the structural analysis again, If yes, with current analysis, you can also select the element 232 and check where it lies using named selection using a worksheet. https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v195/wb_sim/ds_NS_Criteria.html

and then further revisit the mesh in the area to check the quality of the mesh.

-Aniket

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