Configuring the First Order Reliability Method and the Second Order Reliability Method

You can configure the First Order Method (FORM) and the Second Order Reliability Method (SORM).

  1. Double-click the Six Sigma component icon .

    The Six Sigma Component Editor appears.

  2. From the General tab's Analysis Type list, select Reliability Technique, and from the Technique list select First Order Reliability Method (FORM) or Second Order Reliability Method (SORM).

  3. In the Technique Options area, enter the following:

    Option Description
    MPP Maximum Iterations This parameter represents the maximum number of iterations that are run to search for the Most Probable Point (MPP) for each response with limits defined. MPP is the solution of the FORM minimization (i.e., the most likely failure point for a given response).
    Finite Difference Step Size This parameter sets the relative finite difference step size to be used by the reliability method when calculating gradients. The default value is 0.01 (1%).
    Minimum Finite Difference Step This parameter represents the minimum absolute finite difference step size to be used by the reliability analysis method when calculating gradients. The default value is 0.001 (0.1%).
    MPP Absolute Convergence This parameter represents the maximum absolute change in the value of the distance from a constraint surface between two consecutive iterations of the MPP search. For example, if you wanted the search process to stop if the change in the distance from a constraint went below 0.01, you would enter 0.01. The default is 0.0001.
    MPP Relative Convergence This parameter represents the maximum relative change in the value of the distance from a constraint surface during the MPP search. The default is 0.001.

  4. Click OK to save your changes and to close the Six Sigma Component Editor.