The solver engine was unable to converge on a solution for the nonlinear problem as constrained.


I've been working on a left anterior descending artery model on Ansys 19.2 and I'm trying to run a two ways FSI modeling. I've set up transient structural and Fluent. I attempted to run system coupling and I'm receiving two errors message shown below.

Error Message: The solver engine was unable to converge on a solution for the nonlinear problem as constrained.  Please see the Troubleshooting section of the Help System for more information. and

(DP 0) Element 79186 located in Body "WALL_THICKNESS(LAD_with_thickness_stenosis)" (and maybe other elements) has become highly distorted.  You may select the offending object and/or geometry via RMB on this warning in the Messages window.  Excessive distortion of elements is usually a symptom indicating the need for corrective action elsewhere.  Try incrementing the load more slowly (increase the number of substeps or decrease the time step size).  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.  If this message appears in the first iteration of first substep, be sure to perform element shape checking. Named Selections for the offending element can be created via the Identify Element Violations property on the Solution Information Object.

I attempted to solve fluent and structural separately and both were solved without any errors but when they couple it does not solve. 

Please let me know of suggestions that could fix these errors. i attached structural model in .wbpz format but fluent file size is more than 120MB and i couldnot attach it here.

Thank you



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