Objective

Provide practical finite element analysis capabilities within the FreeCAD framework that are easily maintained and extended.

Characteristics

- Robust, automated solution procedures
- Capturing the essence of structural/mechanical behavior (no more, no less)
- Capability to perform a staged analysis, e.g.:
- Excavate deep cavern for water storage in a hydro-electric power generation scheme. stage 1: apply weight for initial stress state, stage 2: excavate, stage 3: apply hydrostatic load.
- Elastic-plastic buckling of a slender structure/component. stage 1: initial imperfection from linear buckling analysis, stage 2: elasto-plastic collapse analysis
- Machining of a cold-formed metal component: stage 1: elasto-plastic loading of the component, stage 2: elasto-plastic unloading of the component, stage 3: remove material.

- Efficient specification of material and analysis control parameters from within the FC UI.
- Output in tabulated form (by node or by integration point) and the VTK pipeline
- Restart possible from any intermediate load steps at any stage.
- Option for (limited) user defined post processing of results through Python calculator.
- Modular approach (with output from any load step in any stage calculated by one module available as initial conditions for another stage in another module).

Generic modules

- Analysis control input
- Extraction of relevant information from FC data structures for specification of finite element geometry, material and boundary conditions.
- Bandwidth reduction
- FE matrix generation
- FE “load vector” generation
- Application of FE displacement boundary conditions
- Decomposition of FE matrix
- Automatic load stepping and arc length control
- Eigenvalue solver
- On-screen analysis progress reporting
- Storage of (user specified) step results (including VTK) and information

- Volume elements
- Interface elements
- Shell/plate elements
- Material-specific stress return routines for plasticity
- Etc.

First steps

The functionality for the basic modules is currently available in the development version of fcFEM, but requires modularizing and optimizing, as well as seamless integration with FreeCAD