Abstract
<title>Abstract</title> <p>Lightweight design of box-type thin-walled structures requires coordinated changes in rib topology, shell dimensions, and openings while preserving load and support definitions, functional interfaces, and analysis conditions during geometry regeneration and finite element (FE) remeshing. This study presents a mechanics-informed semantic-geometry framework in which persistent object identities, connectivity, protected regions, and analysis labels are maintained across heterogeneous design operations. Stage 1 evolves a thickness-reduced dense rib network through sensitivity-guided updates and controlled topology collapse; Stage 2 screens panel and chamfer parameters; and Stage 3 refines explicit moving morphable void (MMV) openings under geometric and compliance checks. The framework transfers structural and analysis information between stages: each trial first undergoes geometric checks and shell-FE transcription/remeshing, and a successfully reconstructed trial is evaluated through the common FE workflow before the applicable stage decision is made. In the numerical case, mass decreased from 304.40 to 280.81 kg (7.75%), compliance from 302.42 to 296.13 N·mm (2.08%), and maximum displacement from 0.04337 to 0.03716 mm (14.32%). The results demonstrate coordinated topology, shape, and opening design while maintaining the reported global mechanical response and explicit geometric features.</p>