Finite Element Analysis for Nozzles

ASME nozzle design rules provide guidance for pressure loads only.  For nozzles supporting external loads the Code requires additional analysis be performed.  WRC-537, also included in COMPRESS, has traditionally been used for this purpose.   COMPRESS now includes nozzle FEA for cases where a more accurate  solution is required.  The COMPRESS FEA engine was created from scratch to address the detailed requirements of ASME Code stress analysis.  It features adaptive meshing, stress error estimating, and is based on advanced Lagrangian 3D elements.

Users can run FEA on existing COMPRESS models or create new designs to quickly obtain detailed stress reports.   No additional steps or third party software is required.  Mesh exports (.inp files) to other FEA programs such as Abaqus® and ANSYS® are available.  This can be used for additional verification if desired.

Nozzle Load Analysis

Nozzle FEA is fully integrated into COMPRESS and is accessed from the Nozzle Loads Analysis dialog.  Loads can be entered using the traditional WRC convention.  A convenient load location option allows loads to be entered at either the shell-nozzle intersection or at the end of the nozzle/flange surface.

FEA Nozzles in COMPRESS

Finite Element Analysis Reports

Detailed ASME Division 2 compliant reports are provided.  Linearized membrane and bending stresses with their respective allowables (per VIII-2, Figure 5.1) are listed in a handy summary table.  The following design information is also reported:

  • FEA model dimensions

  • Mesh and element type summary

  • Model loadings and boundary conditions

  • Linearized stress results for each load case and summary of governing results

  • Categorization of stress results as primary or secondary membrane and bending

  • Results images including Von Mises stress, SCP cross sectional stress, displacement, stress error, and force residual

  • Interactive HTML based plots are linked throughout report for quick access of in-depth results

All of this means one complete report.

FEA Reports in COMPRESS

Interactive Stress Classification Line (SCL) Plot

COMPRESS provides the option to select any SCL on the model to review the details. Simply click on the SCL of interest and results will appear. Results will include calculated Combined Stress, Max and Min Principal Stress, and Von Mises Stress.

Linearized Component Stresses - FEA COMPRESS

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Stress Classification Planes

In addition to SCLs, COMPRESS also provides Stress Classification Planes.

FEA Stress Classification Plane in COMPRESS

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Interactive SCL Plot in FEA COMPRESS

Stress Error

What is Stress Error and why is it important?  Stress Error is the mean difference between un-averaged and averaged stress values. Low stress error is an indicator the mesh and results are stable. Stress error corresponds to stress convergence both locally and globally.

Stress error reporting is also included as part of the reporting.

Stress Error FEA in COMPESS

COMPRESS Featured Capabilities