Elmer Discussion Forum

Hi,

The revision 6198 hopefully contains a working bug fix relating to this issue.

Best regards,
Mika

Hi, I must say that I'm not an expert on material damping, but I'm giving some thoughts anyhow. The only damping mechanism which should be available in this connection is a version of proportional damping where the fully discrete equations are modified by adding the first-order time derivative term ...

Hi,

I guess you have already tried to give "Damping = Real ..." in the material section.

- Mika

Well, this appears to be a linear solver issue which is unrelated to the stress computation that should happen after the displacement solution has been found. Therefore try using other linear solvers, for example GCR iteration or even direct solve.

- Mika

Hi again, As opposed to my previous advice you still give the command "Calculate Stresses = Logical True" in Equation section. This option is not supported in connection with the nonlinear elasticity solver, so try setting Solver 2 ... Calculate Stresses = Logical True ... End - Mika

Hi, The effect of performing the subroutine ComputeChange can be avoided if it is found that "Skip Compute Steady State Change = .TRUE.". One possibility might therefore be to reset also the values of these solver parameters in addition to putting Solver % Variable % SteadyConverged = 1 in...

Hi,

It may be worth noting that if relaxation is applied in connection with the nonlinear iteration, then this modification may have an unwanted impact on how the next nonlinear iterate is computed.

-Mika

Hi, In principle I don't see any reason why stress computation shouldn't work in connection with FSI simulation. It anyhow appears that in your case definition the nonlinear elasticity equations are not really solved as the solver for linear elasticity is used. Therefore consider selecting Procedure...

Hi again, If the force per unit area is cumbersome to calculate, I believe that pointwise loads can also be specified by modifying the sif file as Boundary Condition k Displacement 3 Load = -10000 Target Coordinates(1,3) = 1.0 2.0 3.0 End Here the string before 'Load' ('Displacement 3') specifies th...

Hi, Unfortunately the nomenclature used in Elmer in this connection may not be perfect. The keyword Force is actually used to prescribe a surface force per unit area which is usually referred to as the surface traction. In your setting the total force amounts to F = s * A where s is the prescribed s...