What is mass discretization and how does it work?
Mass discretization in AutoPIPE is a model-refinement method primarily used for modal and dynamic analysis. It automatically adds intermediate analysis nodes, called mass points, along piping spans. These are analysis nodes and do not represent physical piping components.
The additional mass points provide more degrees of freedom, allowing AutoPIPE to calculate additional natural frequencies and mode shapes up to the specified cutoff frequency. Automatic discretization is based on the natural-frequency equation for a simply supported beam.
To enable automatic mass discretization: Home > Model Options > Edit Options
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- Mass point per span (A-Auto, 0-None): Selecting A tells AutoPIPE to automatically determine the required mass-point spacing based on the specified frequency.
- Cutoff frequency: Enter the required frequency
A higher cutoff frequency generally results in a more refined model with more mass points.
Frequently Asked Questions
Q1. Does mass discretization affect static analysis results?
No. Mass discretization should not affect static analysis results. Although additional analytical degrees of freedom are created, they represent the same physical piping system for static analysis.
Q2. Does mass discretization modify the mass and stiffness matrices for static and dynamic analyses?
Yes. The mass and stiffness matrices are modified because mass discretization creates additional mass points and corresponding degrees of freedom.
Q3. Is the same mass/stiffness matrix used in static analysis with mass discretization enabled and disabled?
No. The matrices differ because additional degrees of freedom are introduced when mass discretization is enabled. However, both representations describe the same physical system for static analysis and therefore should produce equivalent static results.