Exam Question
(a) Define fatigue and fracture and specify the conditions under which it occurs. (8)
(b) Describe the different fracture modes and the mechanism of crack propagation in different fracture modes. (8)
Class 2 (2nd Engineer)
MEKG
📅 Oct 2024
Reference Answer
### (a) Definitions and Conditions of Fatigue and Fracture
#### **1. Fatigue**
**Definition:**
Fatigue is the progressive and localized structural damage that occurs when a material is subjected to cyclic or fluctuating stresses. The critical characteristic of fatigue is that failure occurs at a maximum stress level that is significantly below the material's Ultimate Tensile Strength (UTS) and often below its Yield Strength. The process involves the initiation and propagation of a crack, culminating in a sudden and catastrophic failure without significant prior plastic deformation.
#### **1. Fatigue**
**Definition:**
Fatigue is the progressive and localized structural damage that occurs when a material is subjected to cyclic or fluctuating stresses. The critical characteristic of fatigue is that failure occurs at a maximum stress level that is significantly below the material's Ultimate Tensile Strength (UTS) and often below its Yield Strength. The process involves the initiation and propagation of a crack, culminating in a sudden and catastrophic failure without significant prior plastic deformation.
Full answer on MeoMock — surveyor-grade reference answers for 7,000+ written exam questions.
Prepare on Android — MeoMock on Google Play