MBB Beam

The half-symmetry Messerschmidt-Bölkow-Blohm (MBB) beam is a classic topology optimisation benchmark. The left edge is a symmetry plane (horizontal displacement blocked), the bottom-right corner has a vertical roller, and the top-left corner carries a downward point load.

Running

ggp optimize --preset mbb

To save the density image:

ggp optimize --preset mbb --output-dir docs/_static

The preset uses the AMJax FEM solver by default (fem_solver: amjax). To use the SLP algorithm with line search (original recommendation):

ggp optimize --preset mbb --algorithm SLP --use-line-search --output-dir docs/_static

Result

Optimized density field after 400 MMA iterations (40 % volume fraction).

Problem details

Parameter	Value
Domain	60 × 30
Mesh	60 × 30 quads
Formulation	Free 2D
Method	AMNA (MNA)
Components	18
r_gp (σ)	1.0
Min thickness	3 elements
Volume fraction	0.40
Algorithm	MMA
Max iterations	400