PlenFrem — The Complete Guide: Free 2D Frame and Truss Analysis With the Matrix Steps Shown
PlenFrem is free, open-source (MIT) Windows software for linear static analysis of plane frames and trusses. There is no limit on the number of nodes and members, so it works for coursework as well as for quick checks of real structures.
PlenFrem
Ensel Software
Linear static analysis of 2D frames and trusses, no node limit, with the matrix steps shown for learning.
Get it from the vendorWhat you get
- Model building — from scratch, by entering nodes and members.
- Geometry import — from a DXF file or by pasting data from Excel.
- Results — displacements, reactions and internal forces.
- Calculation steps — the member and structure stiffness matrices, just as you build them in class.
- No size limit — no artificial cap on the number of nodes.
Who it suits
Mainly students learning the displacement (stiffness) method: you can solve an exercise by hand and compare every intermediate matrix, not just the final answer. The program is limited to linear analysis in the plane — no 3D, dynamics or code-based design.
Related tools
For a convenient graphical interface with diagrams — Ftool. For trusses only, with influence lines — Truss-101. For 3D frames from an input file — Frame3DD.
Ftool
PUC-Rio, Tecgraf
2D frame and beam analysis — fast to enter, aimed at learning and order-of-magnitude checks.
Get it from the vendorTruss-101
Truss-101 (open-source project)
2D truss solver by the displacement method, with influence lines and a PDF report — a handy study tool.
Get it from the vendor
Frame3DD
Frame3DD Project
3D frame and truss solver driven by an input file — excellent for automation and repeat runs.
Get it from the vendorTom Beam
Tom Holderread
Single-span and continuous beam analysis — shear, moment and deflection, including indeterminate beams.
Get it from the vendorThe bottom line
PlenFrem is one of the best ways to understand what happens inside structural analysis software — completely free and open.