Metallurgy and Materials Science

Ductile fractures occur in materials that undergo significant plastic deformation before failure, while brittle fractures occur with little or no plastic deformation and are characterized by rapid crack propagation.

Fatigue failure is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading. Key components include crack initiation and propagation, S-N curve, endurance and fatigue limits, and the effects of mean stress on fatigue life.

The stress intensity factor approach in fracture mechanics is a method to analyze the stress and strain near the tip of a crack, providing a way to predict when a material will fracture under a given loading and crack size.

The two main categories of fatigue are low cycle fatigue and high cycle fatigue. Low cycle fatigue involves a small number of stress cycles leading to failure, while high cycle fatigue involves a large number of stress cycles leading to failure.

Fracture toughness is a material's ability to resist the propagation of cracks. It is related to brittle fracture as materials with higher fracture toughness are more resistant to brittle fracture, making them less prone to sudden and catastrophic failure.