Schubfresser is a calculator for stiffened shear web structures being developed at the Institute of Structural Mechanics and Lightweight Design (SLA) at RWTH Aachen University. It is written in MATLAB and is intended as a help for students studying lightweight design.

Shear web theory

The shear web theory (in German Schubfeldträgertheorie) is a structural idealization used to calculate structures consisting of thin panels stiffened with bars. Such structures can be found on numerous places such as bridges, aeroplanes, cars and trains. The fuselage structure in the image is an example of a structure which can be modelled using the shear web theory.

  Copyright: Sovxx [CC BY-SA 3.0 (]

This idealization assumes that the shear webs only carry shear loads, while the bars only carry normal forces. Prof. Dr.-Ing. Hans Ebner was one of its main developers since the theory was first published in the late 1930s. The theory can be regarded as one of the precursors of the Finite Element Method (FEM) which is nowadays used to analyze most structural problems.


Program features

  • Graphical UI to model and analyze stiffened shear web structures
  • Calculation and graphical display of static determinacy, reaction forces, shear flows, bar forces and node displacements
  • Calculation of 2D and 3D structures
  • Rectangular, parallelogram and trapezoidal shear webs are supported
  • Loading and saving of files in *.mat format. This way larger structures can be scripted in MATLAB and loaded into Schubfresser
  • Graphics export capabilities into image (PNG) and vector graphic (PDF, SVG) formats

Some not implemented features which are still on our to-do list:

  • Calculation of irregular quadrilateral shear webs
  • Calculation of structures where one shear web side borders the sides of several other webs. As a workaround, using bars with a “near-zero“ stiffness is recommended
  • Modal analysis

At the time being, the GUI is only available in German.





Executables for Linux, MATLAB and Windows:



If you have found bugs or have any question regarding Schubfresser feel free to contact us at