Engineering with Computers (2025)

This repository contains the code and examples for the publication

M. Jäger, S. Wartzack, 
Nodal force distribution of moments on arbitrarily shaped geometries without multi-point constraints, 
Engineering with Computers (2025), DOI: 10.1007/s00366-025-02118-y 

Requirements

• python
• numpy pip install numpy
• gmsh pip install gmsh

Usage

Run Examples

Run any of the example files, and once finished, the gmsh UI will open.
Result views for all load cases, with and without force compensation, will be generated and displayed.

Changing Models

You can copy any example file and modify the loaded model. You can specify the element size and mesh order to be used. For example:

import_and_mesh('step/cylindrical_surface.stp', element_size=0.5, mesh_order=1)

Changing Loads

Loads are specified using the DimTag notation of gmsh, along with a 3x1 vector for each load. For example:

load_case_dimTags: List[List[Tuple[int, int]]] = [[(2, 1), (2, 2)],
                                                  [(2, 1)]]

load_cases: List[np.ndarray] = [np.array([[2000, 0, 3000], 
                                          [1000, 0, 1000]]),
                                np.array([[3000, 700, -1000], ])]

• load_case_dimTags
  • A list of load cases, where each element contains a list of tuples specifying the surface in gmsh to which the load is applied.
  • (2, 1) means the 2nd dimension (surface), face no. 1.
  • To determine the face number in gmsh
    • Run gmsh.fltk.run(),
    • Load the STEP file via File -> Open
    • Go to Tools -> Options -> Geometry
    • Activate Surface labels
• load_cases
  • A list of load cases, where each element contains a NumPy array with shape (N_LOADS, 3) representing the loads in Nm.
  • For each load case, N_LOADS must match the length of the list of surface DimTags.

Hide Result Views

To hide some results, simply uncheck the views you want to hide under Modules -> Post-processing.

Structure

• src
  • common.py - Methods for importing STEP files and plotting.
  • moment2force.py - The method published in the paper.
• examples
  • settings
    • colormap_orange.opt - Configuration file for visualization.
  • step - Contains the 3D data of the surfaces and the truss node.
    • square_surface.stp
    • cylindrical_surface.stp
    • arbitrary_surface.stp
    • truss_node.stp
  • square_surface.py - Example 3.1 and 3.2
  • cylindrical_surface.py - Example 3.3 and 3.4
  • arbitrary_surface.py - Example 3.5
  • truss_node.py - Example 4