Overview

• In nTop 5.0, a third-party dependency will be updated to improve meshing performance. This will affect six native blocks and eight toolkit blocks related to our simulation and analysis workflows. See Section 2.0 Impacted Blocks.
• The previous versions of these blocks will be deprecated (What is a deprecated block?) and will no longer be available. 
• Your previous notebooks can still be opened and viewed in nTop 5.0. Your geometry and analysis results will be cached and available.
• To re-run these blocks in 5.0, you must update them to their newest version. See 5.0 Recommended Actions. Updating the blocks will automatically trigger them to re-run and produce new results. Previously cached geometry and results will be overwritten.

Table of Contents

1.0 Why is this change happening?

2.0 Impacted Blocks

3.0 Example Differences

Example 1 - Remesh Surface applied to a Bracket

Example 2 - Field Optimization

Example 3a - Topology Optimization - Compliance Response

Example 3b - Topology Optimization - Natural Frequency Response

Other Changes

4.0 How does this affect you?

5.0 Recommended Actions

6.0 Effective Release

1.0 Why is this change happening?

• We are upgrading our meshing technology to improve its quality and speed for simulation workflows. As a result of this update, there will be minor differences in the location of nodes and elements produced by select meshing blocks compared to previous versions (versions 4.26 and prior).
• This article documents the impact of this change on simulation and optimization results to alleviate any concerns regarding these workflows. 

2.0 Impacted Blocks

The following table summarizes the blocks that will be updated in nTop 5.0, their function, the latest version number, and the performance difference from releases nTop 4.26 and prior:

 

Examples of the minor differences noted above are provided in 3.0 Example Differences.

In addition, the following toolkit blocks, which internally use one or more of the blocks listed above, will be affected by this update: 

 

These blocks are found in the Architected Materials, Design Analysis, and Lightweighting ribbons, visible to users who opted-in for Toolkits.

3.0 Example Differences

This section contains a few examples detailing the expected differences in meshing and optimization workflows between nTop 4.26 and nTop 5.0.

Example 1 - Remesh Surface applied to a Bracket

 

• As seen above, the Remesh Surface block creates similar meshes; however, the number of faces and vertices can vary between versions. 
• Similar differences can be expected for the following blocks:
  • Native block(s): Remesh Surface with Cyclic Symmetry 
  • Toolkit block(s): FE CAD Shell Mesh, FE Shell Mesh, FE Tetrahedral Mesh, Remesh CAD Face, and Simple Remesh Body

Example 2 - Field Optimization

In this example, a bracket is optimized using a Field Optimization block and a Shell and Infill Parametric Component. The optimization objective is to minimize compliance ( Structural Compliance Response) while reducing volume fraction by 50% (Volume Fraction Constraint). 

 

 

• As seen above, the field optimization workflow in nTop 5.0 converges to a very similar result as 4.26 and requires fewer iterations.  

Example 3a - Topology Optimization - Compliance Response

In this example, a bracket is optimized using the Topology Optimization block with a minimum compliance objective (Structural Compliance Response) while reducing volume fraction by 50% (Volume Fraction Constraint). 

 

 

• The final optimized shapes were similar in both versions, as showcased by the iso-contour plots (set at a threshold of 0.5) and threshold plots.
• Similar differences should be expected when running the Single Body Topology Optimization block, which uses the same topology optimization block internally.

Example 3b - Topology Optimization - Natural Frequency Response

The example below details a bracket optimized using the Topology Optimization block. The optimization objective was to minimize the plate's volume (Volume Fraction Response) while maintaining a natural frequency (first three modes) within a specified band using the Natural Frequency Constraint block. 

 

 

• As seen above, both versions' final optimized shapes were similar, and the modal frequencies show small variations (less than 1E-3 relative error). 

Other Changes 

In addition to the above-mentioned changes, nTop 5.0 includes an updated Ansys *.cdb writer that supports a new APDL block command, ETBLOCK. This command was introduced in Ansys 2023R1 to define element types more concisely and is now generated by the Export FE Mesh, Export FE Model, Export Material, and Export Analysis (Buckling, Modal, Static, and Thermal) blocks. Exporting *.cdb files from these blocks in nTop 5.0 to early versions of Ansys may result in undefined element types in Ansys. Two options are available to correct this incompatibility: 

1. Export an Abaqus *.inp file from nTop and import this file into Ansys Workbench using the External Model component system. Drag and drop the External Model component onto any Ansys Mechanical analysis system's downstream Engineering Data or Model component. 
2. You can manually edit the *.cdb file by commenting out the ETBLOCK and replacing it with the appropriate ET command and keyopts. For more information, see the Ansys Mechanical APDL and Element Reference Guides.   

 

• As seen above, the *.cdb file exported from nTop 4.26 doesn't contain the ETBLOCK. However, the *.cdb file exported in nTop 5.0 has the ETBLOCK section.

4.0 How does this affect you?

• The meshing implementation from nTop 4.26 and prior will not be available in nTop 5.0. Consequently, if you have an existing notebook with older versions of the blocks in the table above, you cannot re-run them until you update the individual block versions. 
• However, when opening files from nTop 4.26 and prior in nTop 5.0 you will have access to the results that were previously generated. You will be prompted to update these blocks to the latest version. If you choose to update the blocks, your previous results will be erased, and the new output will be generated. This will also restore your ability to re-run the blocks.
• As demonstrated in the previous section, this update will have minimal effect on your existing meshing, simulation, and optimization workflows. You can expect a minor difference in the mesh characteristics generated from the updated blocks, but this will not significantly affect the accuracy of the analysis or the quality of the optimized result.

5.0 Recommended Actions

Here are a few scenarios and the recommended actions to follow when using the simulation and optimization tools after this update:

• Accessing results from an existing notebook: No action necessary. You can open a notebook created in a version before the update and access your results. You will notice warning messages in the blocks that require an update. You can ignore these messages if you do not intend to re-run them and generate new results.
• Modifying or reusing a notebook to generate new results: You must select the “Update” button for each block in the block’s warning panel. We do not auto-update your blocks in notebooks created with older versions. This will update it to the latest version and trigger the block to run. Previous results will be erased, and the new output will be generated. Optionally, save a copy of the notebook with a different name before running the update to preserve your old results and workflows.
• Composing a new notebook: No action necessary. All the updated blocks will be available by default as you add them to your notebook from the ribbon or the search bar.
• If you need to generate the same results, do not upgrade to nTop 5.0. If you already have upgraded, contact support@ntop.com to revert back to nTop 4.26.2.

6.0 Effective Release

These changes will be effective in nTop 5.0, expected to be released the week of June 24th.