How To Fix RY363 - Second moment is negative for PH node &1 and RH node &2

SAP Error Message - Details

• Message type: E = Error

• Message class: RY - Messages for RM Basis

• Message number: 363

• Message text: Second moment is negative for PH node &1 and RH node &2

What causes this issue?

The VAR is calculated from the four moments of the distribution
(expected value, variance, skewness and kurtosis) using Cornish/Fisher
approximation. In this case the second moment is observed to be a
negative value.
This results in the VaR being 0 for the respective nodes. The second
moment being negative indicates that the correlation matrix being used
is not positive definite.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Ensure that the correlation matrix is positive definite.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message RY363 - Second moment is negative for PH node &1 and RH node &2 ?

  The SAP error message RY363, which states "Second moment is negative for PH node &1 and RH node &2," typically occurs in the context of structural analysis or finite element analysis within SAP2000 or similar software. This error indicates that there is an issue with the properties of the elements or nodes being analyzed, specifically related to the second moment of area (also known as the area moment of inertia).
  Cause:
  
  
  Negative Second Moment of Area: The second moment of area is a measure of an object's resistance to bending and is calculated based on the geometry of the cross-section. A negative value suggests that there is an inconsistency in the input data, such as:
  
  Incorrect material properties.
  Incorrect cross-sectional dimensions.
  Misconfigured element types or properties.
  Errors in the definition of nodes or connections.
  
  
  
  Modeling Errors: There may be issues in the way the model is set up, such as:
  
  Overlapping elements or nodes.
  Incorrectly defined boundary conditions.
  Non-physical configurations that lead to negative stiffness.
  
  
  
  Solution:
  
  
  Check Cross-Section Properties: Review the cross-sectional properties of the elements associated with the nodes mentioned in the error message. Ensure that the dimensions are positive and correctly defined.
  
  
  Review Material Properties: Ensure that the material properties assigned to the elements are correct and that they do not lead to negative values for the second moment of area.
  
  
  Inspect Node and Element Configuration: Look for any inconsistencies in the node and element configuration. Ensure that all nodes are properly connected and that there are no duplicate or overlapping nodes.
  
  
  Boundary Conditions: Verify that the boundary conditions applied to the model are appropriate and do not lead to unrealistic behavior.
  
  
  Model Simplification: If the model is complex, consider simplifying it to isolate the problem. Remove elements or nodes incrementally to identify the source of the error.
  
  
  Consult Documentation: Refer to the SAP2000 or relevant software documentation for specific guidelines on defining elements and materials, as well as troubleshooting common errors.
  
  
  Related Information:
  
  Software Documentation: Check the user manual or help files for the specific software you are using, as they often contain troubleshooting sections for common error messages.
  Forums and Community Support: Online forums, user groups, or communities related to SAP2000 or structural analysis software can be valuable resources for finding solutions to specific error messages.
  Technical Support: If the issue persists, consider reaching out to the technical support team of the software provider for assistance.
  
  By following these steps, you should be able to identify and resolve the issue causing the RY363 error message in your SAP analysis.