Short Cantilever

A GGP benchmark: a 60 × 30 beam clamped on the left face with a downward point load at the mid-right edge. Eighteen free bars optimise their position, orientation, length, thickness, and membership density using the AMNA (MNA) characteristic function.

Running

ggp optimize --preset short_cantilever

To save the density image directly into the documentation static folder:

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

The preset uses the AMJax FEM solver (JAX-accelerated algebraic multigrid) by default (fem_solver: amjax in the YAML). To switch to the direct LU solver instead:

ggp optimize --preset short_cantilever --fem-solver direct --output-dir docs/_static

Result

Optimized density field after 250 MMA iterations (40 % volume fraction, C = 74.3).

Problem details

Parameter	Value
Domain	60 × 30
Mesh	60 × 30 quads
Formulation	Free 2D
Method	GP
Components	18
r_gp (σ)	0.5
Volume fraction	0.40
Algorithm	MMA
Max iterations	250
Compliance	74.3