Tolerance on limit displacement boundary condition
Posted: 03 Jul 2017, 19:24
I'm trying to use a limit displacement boundary condition in an elastic deflection problem, and was wondering what, if any, solver settings affect the tolerance of the applied limit.
This is my current .sif
Without Boundary condition 4 the minimum Z displacement I am seeing is -.00118, with Boundary condition 4 this is reduced to -.00088, so I am seeing an effect, but I would like to drive it closer to zero.
This is my current .sif
Code: Select all
Header
CHECK KEYWORDS Warn
Mesh DB "." "."
Include Path ""
Results Directory ""
End
Simulation
Max Output Level = 5
Coordinate System = Cartesian
Coordinate Mapping(3) = 1 2 3
Simulation Type = Steady state
Steady State Max Iterations = 1
Output Intervals = 1
Timestepping Method = BDF
BDF Order = 1
Solver Input File = case.sif
Post File = case.ep
End
Constants
Gravity(4) = 0 -1 0 9.82
Stefan Boltzmann = 5.67e-08
Permittivity of Vacuum = 8.8542e-12
Boltzmann Constant = 1.3807e-23
Unit Charge = 1.602e-19
End
Body 1
Target Bodies(1) = 1
Name = "Body 1"
Equation = 1
Material = 1
End
Solver 1
Equation = Result Output
Procedure = "ResultOutputSolve" "ResultOutputSolver"
Output File Name = case
Output Format = Vtu
Exec Solver = After Simulation
End
Solver 2
Equation = Linear elasticity
Procedure = "StressSolve" "StressSolver"
Variable = -dofs 3 Displacement
Apply Limiter = Logical True
Exec Solver = Always
Stabilize = True
Bubbles = False
Lumped Mass Matrix = False
Optimize Bandwidth = True
Steady State Convergence Tolerance = 1.0e-5
Nonlinear System Convergence Tolerance = 1.0e-9
Nonlinear System Max Iterations = 20
Nonlinear System Newton After Iterations = 3
Nonlinear System Newton After Tolerance = 1.0e-3
Nonlinear System Relaxation Factor = 1
Linear System Solver = Direct
Linear System Direct Method = Umfpack
End
Equation 1
Name = "elast_direct"
Active Solvers(2) = 1 2
End
Material 1
Name = "Austenitic stainless steel (AK Steel 201)"
Heat expansion Coefficient = 15.7e-6
Heat Conductivity = 16.2
Heat Capacity = 500.0
Mesh Poisson ratio = 0.3
Density = 7810.0
Poisson ratio = 0.3
Youngs modulus = 197.0e9
End
Boundary Condition 1
Target Boundaries(8) = 2 6 9 10 16 17 19 20
Name = "fix_z"
Displacement 3 = 0
End
Boundary Condition 2
Target Boundaries(8) = 21 24 31 41 42 43 44 50
Name = "seal_load"
Force 3 = 71258503
End
Boundary Condition 3
Target Boundaries(1) = 28
Name = "fix_xy"
End
Boundary Condition 4
Target Boundaries(4) = 5 7 13 25
Name = "contact"
Displacement 3 Lower Limit = Real 0.00000000
End