Selection of Material and Shape Case Studies 1/11/2019
Floor Joists: Wood or Steel? Aim: Light, stiff and strong joist for supporting floors in buildings Traditionally, wood with rectangular section of aspect ratio 2:1 is used; steel I-beam with 15Be25 could be used instead Which one is better? 1/11/2019
Floor Joists: Wood or Steel? 1/11/2019
Floor Joists: Wood or Steel? 1/11/2019
Floor Joists: Wood or Steel? While M1 are more or less the same, M3 of pine wood is much better than that of steel The cellular structure is the nature’s answer to bending! But steel can be standardized. 1/11/2019
Forks for a Racing Bicycle Aim: light strong frame Loading on frame is not obvious, but that on the fork is predominantly bending. First maximize f2/3/, regardless of shape 1/11/2019
Forks for a Racing Bicycle Six materials are singled out and shown in the next page All except wood can be made into tubes 1/11/2019
Forks for a Racing Bicycle 1/11/2019
Efficient Spring Consider a leaf spring, the stored energy The bending stiffness The force F is limited by yielding Substituting F and SB into the equation for U For torsion bars or helical springs 1/11/2019
1/11/2019