#102: What is “Maximum Value of Constraints” column in iteration history for SOL200?

#102: What is “Maximum Value of Constraints” column in iteration history for SOL200?

Answer:
This refers to the maximum normalized constraint over all constraints in the design model. A positive value indicates constraint violation, a negative value constraint satisfaction, and a near zero value a critical constraint. Normalized constraints are used in Nastran to remove the dependence of the constraint value on the magnitude of the underlying responses.

If hard convergence is achieved, it will be noted in the Summary of Iteration History table. This test compares the results of two successive finite element analyses and is a conclusive test of convergence at the design cycle level. All constants used in the convergence test can be changed from their defaults using the DOPTPRM Bulk Data entry.

There are essentially two types of converged designs:

1. Convergence to a feasible design
2. Convergence to a best compromise infeasible design

If all constraints are satisfied, a feasible design has been found, and can be confirmed by a maximum constraint value that is less than GMAX (default = 0.005).

If one or more constraints are violated at the converged design, the conclusion is that the optimizer has done the best it can, and returned with a design representing the best compromise between least objective function, and violated constraints. This is actually useful design information, since it indicates that one or more constraints need to be either relaxed or restated in order to achieve a feasible design.


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S U M M A R Y O F D E S I G N C Y C L E H I S T O R Y
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*** USER INFORMATION MESSAGE 6464 (DOM12E)
RUN TERMINATED DUE TO HARD CONVERGENCE TO AN OPTIMUM AT CYCLE NUMBER = 33.