I am simulating FSI of multiphase flow (upward flow) through a 2inch pipe with bend in ANSYS 17. The mesh is triangular 293608 elements and the only supports are fixed supports at the 2 ends of the pipe. Step size for the simulation is 1E-06. When I run the simulation, I get this the pop message:
The program can't start because AnsMPI.dll is missing from your computer. Try reinstalling the program to fix this problem.
But the simulation keeps attempting to run until it eventually stops with the error message below
DP 0) Element 241459 located in Body "Pipe Structure" (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.
When I repeat this simulation with a smaller number of mesh element 67000 (quads and wedges) in ANSYS 18, the error is:
"(DP 0) A solver pivot warning or error has been detected in the UY degree of freedom of node 10890 located in Pipe Structure. This is usually a result of an ill conditioned matrix possibly due to unreasonable material properties, an under constrained model, or contact related issues. Check results carefully. You may select the offending object and/or geometry via RMB on this warning in the Messages window."
Please I will really appreciate any help on how to solve this problem.