07-03-2011, 09:45 AM
PREPARED BY
ABHISHEK KUMAR SHARMA
Abhishek Sharma ME-3.pptx (Size: 1.44 MB / Downloads: 287)
Fracture Mechanism In Design And Failure Analysis
Introduction
Separation of solid into two or more pieces under applied load or stress
Applied load or stress may be tensile or compressive in nature
Fracture due to
1. Crack initiation
2. Crack propagation
Principles of Fracture Mechanics
Quantitative study of failure is called fracture mechanics
Fracture mechanics is the relationship between
Material properties
Stress level
Presence of cracks/defects in material
Types of crack-propagating mechanisms
The aim is: “ design to prevent structural failure”
Intention is to allow better design we design, only works well if ……………fracture and inter-relationships and limitations.
Classification
Fracture in material can be broadly classified in two main category;
Ductile Fracture
Occurs after prolonged plastic deformation.
Crack initiates from formation of voids and propagates slowly.
Ductile Þ sy < sf
] yields before fracture
Mechanism of Ductile Fracture
Original specimen
Necking
Crack Nucleation
Crack Growth
Shearing at surface
Fracture