Mechanical Engineering

High-temperature brake operation requires materials with excellent thermal conductivity to dissipate heat quickly, preventing brake fade and maintaining friction coefficient stability.

Equivalent dynamic load P = X × Fr + Y × Fa = 0.56 × 5 + 1.8 × 2 = 2.8 + 3.6 = 6.4 kN (approximate)

T = μ × F × r × n, where n = number of friction surfaces = 5 × 2 = 10. Therefore, T = 0.3 × F × r × 10 = 3.0 × F × r

At lower speeds (static loading), stress concentration has more severe effects as fatigue is not a factor and stress peaks can cause immediate failure. Larger fillet radii reduce stress concentration.

The L10 life (in revolutions) is directly affected by both the equivalent dynamic load and speed according to the bearing life equation: L₁₀ = (C/P)³ × 10⁶

Tensile load = σ × A = 120 × (π/4) × 16² × 6 = 72.6 kN (approximately)

Woodruff keys provide better shock resistance and are less likely to loosen under load reversals due to their semi-circular design and secure seating.

Using the formula for rim thickness: t = (ρ × v²)/(σ_allowable), where v = π × D × N/60 = 25.13 m/s, and ρ for cast iron ≈ 7200 kg/m³, t ≈ 25 mm

Using T = (P × 60)/(2π × N) and τ = (16T)/(π × d³), with τ_max = σ_y/(2 × FOS) = 80 MPa, solving gives d ≈ 35.2 mm

Hydrodynamic lubrication relies on the wedge effect: as the journal rotates, it wedges lubricant into the narrowing gap, building pressure that supports the load and maintains a fluid film.