Hi everyone,
i'm using the following unit system:
geometry: mm
material density: g/mm^3
young modulus: Pa
This is my sif file:

Header
CHECK KEYWORDS Warn
Mesh DB "." "."
Include Path ""
Results Directory ""
End
Simulation
Max Output Level = 4
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 = 5.67e08
Permittivity of Vacuum = 8.8542e12
Boltzmann Constant = 1.3807e23
Unit Charge = 1.602e19
End
Body 1
Target Bodies(1) = 1
Name = "Body 1"
Equation = 1
Material = 1
End
Solver 1
Equation = Linear elasticity
Eigen System Values = 10
Procedure = "StressSolve" "StressSolver"
Variable = dofs 3 Displacement
Eigen System Select = Smallest magnitude
Eigen Analysis = True
Exec Solver = Always
Stabilize = True
Bubbles = False
Lumped Mass Matrix = False
Optimize Bandwidth = True
Steady State Convergence Tolerance = 1.0e5
Nonlinear System Convergence Tolerance = 1.0e7
Nonlinear System Max Iterations = 20
Nonlinear System Newton After Iterations = 3
Nonlinear System Newton After Tolerance = 1.0e3
Nonlinear System Relaxation Factor = 1
Linear System Solver = Direct
Linear System Direct Method = Umfpack
End
Equation 1
Name = "Equation 1"
Active Solvers(1) = 1
End
Material 1
Name = "Material 1"
Density = 0.0028
Poisson ratio = 0.33
Youngs modulus = 73e9
End
Boundary Condition 1
Target Boundaries(1) = 10
Name = "vincoli"
Displacement 3 = 0
Displacement 2 = 0
Displacement 1 = 0
End
Boundary Condition 2
Target Boundaries(1) = 28
Name = "vincoli"
Displacement 3 = 0
Displacement 2 = 0
Displacement 1 = 0
End

Do the eigenvalues coming out from solver in Hz^2 unit?
so for the first frequency in hertz do i have to make the sqrt of the first eigenvalue?
because i found the first eigenvalue : 105500425.49 that correspond to 10271 Hertz. it is too high...where i'm wrong?
thank you
eigenvalue problem

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Re: eigenvalue problem
Hi
The eigenvalue is c=w^2=(2pi*f)^2. Hence the frequency is sqrt(c)/(2*pi).
Peter
The eigenvalue is c=w^2=(2pi*f)^2. Hence the frequency is sqrt(c)/(2*pi).
Peter