Motor bracket redesign with FEA for a 30% mass saving

Hessler sells gear-motor drives for airport baggage and parcel conveyors. Each drive hangs from an L-shaped bracket welded from S355 steel plate: a 220 × 160 × 12 mm base, a 180 × 200 × 10 mm upright and two 8 mm gussets. It weighs 6.2 kg and costs €46.80 to make.

A large logistics customer has asked for a lighter drive so two fitters can lift it at height without a hoist. Their target is a 30% saving on the bracket, which means 4.34 kg or less. Sales has already said yes. Engineering now has to prove it is safe.

The loads are known. The motor and gearbox weigh 42 kg with their centre of mass 160 mm in front of the upright. The belt pulls 2.0 kN horizontally at 95 mm from the upright face. During transport and emergency stops the design rule is 3 g vertical on the motor mass. The motor pilot face must deflect no more than 0.15 mm under the working load, or the belt tracks badly. Peak von Mises stress must stay under 60% of yield.

Your job: - write the load cases and check the existing bracket by hand; - model it in FreeCAD FEM or Fusion 360 (student licence) and show the mesh is converged; - redesign it, for example with pockets, a thinner upright with better gussets, or a bent sheet design, and check it with FEA; - issue a drawing with general tolerances to ISO 2768 and GD&T to ISO 1101 for the motor mounting holes; - estimate the new part cost.

All of this is done in software. You do not need the physical part. Done looks like a redesign at or under 4.34 kg that passes stiffness and stress, a hand calculation that agrees with the FEA within 15%, a drawing a supplier could quote from, and a one-page cost comparison.