Nonlinear Analysis Control






Specify the iteration method and convergence conditions for performing a nonlinear analysis reflecting large displacement and material nonlinear analysis . The large displacement analysis can be applied to both general static analysis and construction stage analysis. Material nonlinear analysis can only be applied to static analysis. Prior to an analysis, specify the sequence of applying loads in Loading Sequence for Nonlinear Analysis, and define the convergence criteria for nonlinear analysis in Nonlinear Analysis Control. Specified loading sequence is effective when NewtonRaphson and DisplacementControl are selected as the Iteration Method. Large displacement analysis and material nonlinear analysis can be performed on Truss, Plate, Plane Stress, Plane Strain, Axisymmetric, and Solid elements.
Note Tensiononly/Compressiononly element will be changed to Truss element in Eigenvalue Analysis. 







From the Main Menu select Analysis > Analysis Control > Nonlinear Analysis Control. 





Nonlinear Type
Select a type of nonlinear analysis
Geometry Nonlinear: Geometric large displacement nonlinear analysis
Material Nonlinear: Material plasticity static analysis
Note 1 Following elements can be used in geometry nonlinear analysis and/or material nonlinear analysis
(O : Analysis can be performed. / X : Analysis cannot be performed. / △ : Corresponding elements are considered as linear elements and then analysis can be performed.)
Note 2 Geometry nonlinear analysis and/or material nonlinear analysis cannot be performed for the items marked ×.
In case of Beam End Release and Plate End Release, the material nonlinear analysis cannot be performed for the following case: 1) When Load > Nonlinear Analysis > Loading Sequence for Nonlinear Analysis is used
Note 3 Analysis result is produced only at both I & J ends of elements in geometry nonlinear analysis.
Iteration Method
Select the method of iteration.
If NewtonRaphson is selected
Number of Load Steps
Maximum Number of Iterations/Load Step
If ArcLength is selected
Number of Increment Steps
Maximum Number of Iterations/Increment Step
Maximum Displacement Boundary
Initial Force Ratio for Unit ArcLength (%) Ratio of the Initial Force per Unit ArcLength
Note Real number (decimal) can be input.
If DisplacementControl is selected
Number of Displacement Steps
Maximum Number of Iterations/Increment Step
Master Node
Direction
Maximum Displacement
Convergence Criteria
Specify the basis on which to assess the convergence.
Energy Norm
Displacement Norm
Force Norm
Note
: Remove the conditions for a nonlinear analysis.
Load Case Specific Nonlinear Analysis Control Data
The above defined Iteration Method is applied individually by load cases. If the same iteration method is applied to all the load cases, this dialog box need not be used.
Iteration Method
Data for NewtonRaphson/ArchLength/DisplacementControl Method
Step: Number of Load Steps entered
Load Factor: load factors for each increment, which can be userdefined or autogenerated by clicking on the Generation button.
8 steps are generated in the Dialog box above in accordance with the Number of Load Steps entered.
Load Factors can be userdefined, or autogenerated by clicking on the button.
Note 1 When ArcLength Method (ALM) is used to solve the nonlinear equilibrium equation, a real number can be inputted into the 'Initial Force Ratio for Unit ArcLength (%)' text box in Nonlinear Analysis Control.
Note 2 In nonlinear analysis, the sequence of applying loads can be defined in Loading Sequence for Nonlinear Analysis. Loading sequence can be used when NewtonRaphson and DisplacementControl are selected as Iteration Method. In one model, both DisplacementControl and NewtonRaphson iteration method can be used. However, the load case specified as NewtonRaphson iteration method must be applied in advance of the load case specifined as DisplacementControl method.


