PROJECTS
Pivot Stress Group has been involved in many custom client projects. Below are a few examples of the versatility of the automation that we deliver.
Pressure Gradient Loads Mapping Tool
This Excel Add-in Form Application is used to apply pressure gradient loads to external airframe surfaces.
This tool can rapidly batch create multiple sets of PLOAD4 load cards. The analyst simply creates a table of pressure loads defined in the same coordinate system as the finite element model.
The tool only requires two other inputs: the model bulk data file and a Patran group session file which contains a group which defines the 2D elements that are to be loaded.
The algorithm behind the tool reads the group session file and retrieves all the elements to be
loaded. It reads the model bulk data file and extracts the definition of each element, including
all GRID cards defining the elements' vertices and the coordinate systems in which the GRID cards are defined. It then reads the pressure loads map from the Excel table and linearly interpolates where each elements' vertices lie within the loads map and loads each element accordingly.
The output is a NASTRAN/Patran readable text file that can be included in the model bulk data file.
Loads Database Tool
This powerful suite of tools is used to create multiple databases of program level loads and allow employees access to the loads through a simple to use Excel Add-in.
This suite of tools contains multiple programs written in multiple languages to achieve it function. The first component is a standalone executable that batch reads multiple NASTRAN f06 results files, extracts element loads and inserts them into the database. The second component is the database which is optimized to store NASTRAN static loads and isolate them by program, by loop iteration, and by revision. The loads are stored unfactored however, load case factors are also stored in the database. Upon retrieval the loads can be queried factored or unfactored. The final component is the loads retrieval tool written in Excel VBA as an Add-in. The Add-in Ribbon suite contains multiple tools: program level loads query tool, loads sorting tool, a database query tool to check the status of the databases, and a few database administrator tools for the loads engineers to maintain the database without having or needing SQL knowledge.
MRB FEM Isolation Tool
This standalone executable program is used to create derivative finite element models with mock-up damage that are isolated in their own sub-directories.
The analyst identifies the damaged structure using a Patran group written out in a session file. The file or files that contain the affected elements and grids are duplicated in a newly created sub-directory. The original bulk data file is duplicated, and the affected elements and grids are commented out allowing the analyst to add the damaged structure back in its place. The bulk data file reader is a versatile algorithm that allows for use of nested daughter data files referenced using “include” statements. A complete record of affected files is recorded, duplicated, and filed into the isolated sub-directory. All referenced file links are recreated in the top-level bulk data file and properly point to the new file location.
Spring Coincident Grid Check Tool
This Excel Forms Application checks that all spring-type elements are defined by grids that are coincidently located.
This simple tool reads through a NASTRAN bulk data file and collects all CELAS2 and CBUSH elements. It reads all GRIDs associated with those elements and checks their coordinates. The tool has the capability to transform GRIDs defined in alternate coordinate systems and compare them in the global coordinate system. The tool reports out its findings in a formatted and sorted Excel Worksheet.