Chair
A chair frame tough enough for a police station.
Material selection for a rugged desk chair: Ashby plots, a stiffness-per-weight index and semantic scales for how tough it feels. Ductile cast iron, ribbed and hollow where it counts.
Ribbed and hollow: stiffness kept, mass dropped.
One-piece casting, with fewer interfaces to fail.
Standard fasteners and replaceable glides. Parts wear out, not the chair.
- Brief
- Choose the frame material for a police department's desk chair, one resilient against both gunfire and coffee spills.
- Role
- Individual: requirements, Ashby screening, a performance index and semantic scales.
- Outcome
- Ductile cast iron, ribbed and hollow where it counts, with 34% less mass.
-34%
frame mass
Numbers steer, feel confirms.
- 01
Filter
Keep only what meets cost, strength and recyclability.
- 02
Rank
Chase stiffness per weight, P = √E / ρ.
- 03
Feel
Rugged and warm matter. Cast iron reads tough.
