RCO Training – Mechanical Practice Test

Fatigue failure comes from repeated or fluctuating stresses causing crack initiation and growth over many cycles. The most direct way to reduce this risk is to design to minimize local stress concentrations, ensure loads are balanced, and keep the contact surfaces well protected with adequate lubrication. Sharp corners act as stress risers, so using fillets and smooth transitions lowers peak stresses under cyclic loading. Balanced operation prevents unexpected overloads that would otherwise drive higher stress during certain parts of the cycle. Adequate lubrication reduces friction and wear, lowers surface damage, and helps manage heat, all of which slow crack initiation and propagation. Relying solely on high-strength materials doesn't fix geometry-related stress risers, and reducing lubrication increases wear and friction, which worsens fatigue. So the best practice is the integrated approach described here.