Applies To
Product(s):	AutoPIPE
Version(s):	ALL;
Environment:	N/A
Area:	Analysis
Original Author:	Bentley Technical Support Group
Date Logged & Current Version	Sept. 2016 10.01.00.09

Problem:

When analyzing a model the following occurs:

--------------------------- Confirm --------------------------- The load case did not converge. Do you wish to continue iterating? --------------------------- Yes No Cancel ---------------------------

The default number of iterations is 30, Can this value be increased?

Solution:

Convergence is an iterative process that requires multiple passes in order to reduce the errors associated with initial estimates to an acceptable level. After each iteration, the [U] matrix is investigated for any effect on the stiffness matrix [K]. If [K] is affected, a new stiffness matrix is formed and the analysis is repeated until a solution is obtained. Since each loading condition can affect the system differently, a separate [K] matrix may be required for each defined load case. The iterative solution stops when all convergence criterion have been met (bearing, friction, & soil force and displacement).

Convergence problems may be alleviated by reducing the friction restraint stiffness. Lower friction stiffness will more-readily distribute friction loads throughout the system and speed or allow nonlinear convergence but this lower stiffness will also affect the accuracy of the results. Lower stiffness values permit more "non-sliding" movement, but given the indeterminate nature of the friction problem in general, this error may not be crucial.

To change the number of iterations in AutoPIPE select Load> Static analysis sets> Modify an analysis set> Gaps/Friction/Soil option must be checked ON, press OK button, on the non-linear analysis dialog screen change iteration setting to different value.

04. How to change number of iterations for non-linear static analysis?

Problem:

Solution:

See Also