Change section geometry before adding material: flanges, beads, offsets, formed hat stiffeners, shorter unsupported spans and better fastener locations are usually more efficient. In a simplified beam model, bending stiffness scales roughly with t³, while formed depth can increase second moment I dramatically.
Values in this article support engineering screening during design review, RFQ and prototyping. They do not replace formal calculations, material data sheets, qualified procedures or contractual standards.
ORDER-OF-MAGNITUDE CHECK
For equal width/material, increasing flat sheet from 1.0 to 1.2 mm adds 20% mass and theoretically 72.8% bending stiffness. Yet a 10–15 mm flange or shallow bead can raise local I with less mass. A cover is a plate, not a 1D beam; boundaries, cutouts and local buckling alter the result, so confirm by FEA and prototype deflection/modal tests.
DESIGN ACTIONS
- Divide broad flats into shorter spans; run beads through high-displacement zones toward supports. - Flange holes/louvers to stiffen and remove sharp edges, while checking forming limits. - Do not terminate long straight beads abruptly in a weak area; fade/radius ends to reduce oil-canning and read-through. - Place fasteners near load input; excessive pitch lets panels drum. - For noise, separate stiffness from damping: beads move natural frequency; constrained damping reduces resonance amplitude.
PROJECT CHECKLIST
Load/press point; allowable deflection; modal frequency; span; bead height/direction; openings; fastener pitch; forming and read-through.