Fatigue and Fracture in Materials: Types and Examples Explained

Fatigue and fracture are two types of material failure that are commonly encountered in engineering and structural design. They can occur as a result of repeated or cyclic loading, which gradually weakens the material until it eventually fails. In this article, we will explore the concepts of fatigue and fracture in materials, and examine some common examples and types of these phenomena.

What is Fatigue and Fracture?

Fatigue is a type of material failure that occurs as a result of repeated or cyclic loading, such as vibration or flexing. Over time, the material becomes weaker and more susceptible to cracking, which can eventually lead to a complete failure of the component. Fatigue is particularly relevant for materials used in applications that experience cyclic loading, such as aircraft wings, car suspension systems, and wind turbines.

Fracture, on the other hand, is a type of material failure that occurs as a result of a single, sudden load or impact. This can cause the material to crack or break, and can be particularly dangerous if the component is under a high load or pressure. Fracture can occur in any material, but is particularly relevant for materials used in high-pressure applications such as pipelines, pressure vessels, and nuclear reactors.

What are Examples of Fatigue Materials?

Fatigue can occur in any material, but some materials are particularly susceptible to this type of failure. Metals are a common example of fatigue-prone materials, particularly those that are subject to cyclic loading, such as aircraft components or automotive parts. Other materials that can be prone to fatigue include composites, polymers, and ceramics.

One common example of fatigue in materials is the failure of aircraft wings. Aircraft wings are subject to repeated cycles of stress and strain as the plane takes off, flies, and lands. Over time, this can cause the material to weaken and crack, which can eventually lead to a catastrophic failure of the wing. To prevent this, aircraft manufacturers carefully monitor and test the materials used in their wings to ensure they can withstand the stresses of repeated use.

Types of Fatigue in Materials

There are several types of fatigue that can occur in materials, each with its own unique characteristics and failure modes. Some common types of fatigue include:

  1. Low-cycle fatigue: This type of fatigue occurs when the material is subjected to a relatively small number of cycles, but at a high load or stress level. This can cause the material to fail quickly, and is often seen in materials subjected to severe loading conditions.
  2. High-cycle fatigue: This type of fatigue occurs when the material is subjected to a large number of cycles, but at a relatively low load or stress level.

What are the 3 stages of fatigue?

  • 1st stage: Crack initiation
  • 2nd stage: Crack growth
  • 3rd stage: Failure