Nonlinear Static Analysis
In the modeling phase, you have the option to specify the configurations for nonlinear static analysis. Nonlinear static analysis serves various purposes, including:
 Analyzing structures equipped with tensiononly bracing.
 Analyzing cable structures.
 Conducting static analysis that takes into account the impact of geometric nonlinear behavior.
Advance Design software conducts calculations for both linear and nonlinear analysis, with the exception of structures that incorporate cable elements, which exclusively require nonlinear analysis.
A nonlinear static family can consist of multiple scenarios or cases. The parameters for nonlinear static analysis are defined within the properties window of the Static non linear load case.
How to create a nonlinear static analysis family
 Menu: select Settings > Nonlinear Static Analysis.
 Project Browser: rightclick Settings and select Non linear static from the context menu.
 A nonlinear static analysis family is created in the Project Browser under Settings along with a nonlinear static case.
Nonlinear static analysis family
How to select nonlinear analysis type
In the properties window of the Static non linear load case, Settings category, select the appropriate Calculation controlled by option:
 Load increments: a Newton Raphson force control solver, in which, in successive iterations, the load is applied based on the increase in force.
 None: a displacement control solver, in which, in successive iterations, the load is applied based on a displacement increment.
How to select the static cases for the static nonlinear analysis

In the properties window of the Static non linear load case, Settings category, click Analyses options > , to display the Non Linear Analysis Options dialog box.

In the Non Linear Analysis Options dialog box, click Add / Remove analyses to display the Select the static analyses dialog box and select the cases for the nonlinear analysis:
Select the static cases for the static nonlinear analysis

From the Available analyses list, select the cases to add.
Tip
 To select a range of consecutive items, keep the <Shift> key pressed while clicking the first and the last element of the range, or click the first element of the range and drag to the last element. Alternatively, use the dash: 110.
 To select nonconsecutive items, keep the <Ctrl> key pressed while clicking each item to select, or separate the identifiers with a space: 1 5 10.
 The selection methods described above can be combined: by entering 1 2 102104, the selected cases are 1, 2, 102, 103 and 104

Enter the coefficient value in the Coefficient field.

Click the Add button to place them in the Selected analyses list, which will be used for the nonlinear analysis.

Click OK to apply and close.
Selection options
 All: selects all the available load cases and combinations.
 None: cancels the current selection.
 Analysis type dropdown list: allows the selection of all static load cases or all static combinations. The selection is additive.
 Codes or identifiers: selects all load cases or combinations which share a certain code, when entering the code in the corresponding field. It also selects cases by their identifiers.
How to configure the static nonlinear analysis
The selected cases appear in the Non Linear Analysis Options dialog box. For each case, the nonlinear analysis options can be configured. Depending on which control method has been selected, different are displayed:
a) Nonlinear controlled by load increments
Configure the nonlinear analysis options  Load increments
Add/Remove analyses: opens the Select the static analyses dialog box which allows the selection of load cases and combinations for the nonlinear analysis.
Load case or combination
 Identifier  name: displays the name of the case (i.e., load case or combination) used in the nonlinear analysis.
 Coefficient: defines the scale coefficient for each case.
Incrementation
 Number: the number of analysis steps. NOTE: The time duration of the nonlinear analysis directly depends on the number of steps, therefore start by introducing smaller values for this parameter. If the analysis does not converge within the initial number of steps, rerun the analysis after increasing this number of saved steps.
 Iterations by step: controls the number of iterations per step. The default value of 50 is suited for most cases.
 Stabilize iterations: iterations are stabilized up to this iteration number (in each step).
Save results
 Frequency / step: the rate of the results are saved per step. By default, the results are saved only once (in their final state).
Update stiffness
 Mode: defines the method for updating the stiffness matrix:  i.e., complete (default), quasiNewton, or none.
 Period: defines the update rate: by iteration inside each step, for the complete update mode or by step, for the quasiNewton update mode.
Convergence: the solver iterates to achieve equilibrium at each step of the analysis. Equilibrium is achieved when the magnitude of the force error is smaller than the convergence tolerance. The convergence tolerance for energy, force and displacement can be viewed or modified. Each of the parameters can be modified at the same time for all selected load cases and combinations by using the Apply to selected items function:
 Parameters dropdown list: allows the selection of the parameter to modify (coefficient, number, iterations by step, etc.).
 Parameters field: allows the definition of the selected parameter.
 Apply to selected items: applies the modification on all selected load cases and combinations.
b) Nonlinear controlled by displacement increments
Configure the nonlinear analysis options  Displacement increments
NOTE: Below are mentioned only the parameters different from the case of load increments.
Displacement control node
 Point: ID of the point that represents the control node where the displacement is measured.
Note: A point must be previously defined at the location where it is wanted to monitor the displacement. For each load case, a different point can be used.
Define a point to be used as a control node
 Degree of freedom: degree of freedom that controls the nonlinear analysis: DX, DY, DZ, RX, RY, RZ
 Displacement magnitude: magnitude of the displacement/rotation at which the nonlinear analysis stops.
How to delete nonlinear static analyses
 In the Project Browser, rightclick a nonlinear static analysis (i.e., family or case) and select Delete from the context menu.
 In the Project Browser, click a nonlinear static analysis (i.e., family or case) and press <Delete>.
 The selected analysis is deleted. When deleting a nonlinear static analysis family, all the corresponding load cases are deleted.
See Also
Related Topics