Error at the Results - High varation of Stiffness within materials

Hi Forum, I hope you are well.

I have been trying to analyse a quite simple supported 2D Beam however with a quite consider a variation of the stiffness and thickness of the materials.

As the photo below shows, it's kind of a flitch beam (sandwich beam) where the top and bottom is an 18mm thk and E=28GPa with the middle material behaving as a 300mm thk Foam (E=0.15). Both materials have Poisson's ratio of 0.2 and 0.3 respectively.

Both extremities have a 25mm thk steel support and a distributed load of 1.5Mpa acting at the top flange.

Once I try to evaluate the Equivalent Stress the following error shows: "Solver Pivot warnings or errors have been encountered during the solution. This is usually a result of an ill-conditioned matrix possibly due to unreasonable materials properties, and under constrained model, or contact related issues".

The only way that I was able to run the mesh was with the Pivot Checking Off and as a Quasi-Static Solution to analyse in a slow movement and the result is the top flange with an unrealistic strain and deformation.

Does anyone have encounter this problem? Is related to the high variation of stiffness properties and area of the materials? There is a solution that I should try?

Thank you for your time and help,

Andre Pitt

Best Answers


  • Hi

    Thank you both for the support,

    I've shared the faces in SPC and added a frictioneless support on the rear face of the element. The analysis ran without errors, thank you!

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