What is linear elastic fracture mechanics?
Linear elastic fracture mechanics (LEFM) is based on the analysis of cracks in linear elastic materials. It provides a tool for solving most practical problems in engineering mechanics, such as safety and life expectancy estimation of cracked structures and components.
What is the central assumption of linear elastic fracture mechanics?
Linear Elastic Fracture Mechanics (LEFM) first assumes that the material is isotropic and linear elastic. Based on the assumption, the stress field near the crack tip is calculated using the theory of elasticity. When the stresses near the crack tip exceed the material fracture toughness, the crack will grow.
What is Griffith theory?
The Griffith theory states that a crack will propagate when the reduction in potential energy that occurs due to crack growth is greater than or equal to the increase in surface energy due to the creation of new free surfaces. This theory is applicable to elastic materials that fracture in a brittle fashion.
What is a linear elastic material?
A linear elastic material is a mathematical model used to analyze the deformation of solid bodies. It is useful to compute the relation between the forces applied on the object and the corresponding change in shape. In other terms, it relates the stresses and the strains in the material.
What is KIC?
A Knowledge and Innovation Community (KIC), is a highly autonomous partnership of leading higher education institutions, research organisations, companies and other stakeholders in the innovation process that tackles societal challenges through the development of products, services and processes and by nurturing …
What is Griffith theory of brittle fracture?
Definition. The Griffith theory states that a crack will propagate when the reduction in potential energy that occurs due to crack growth is greater than or equal to the increase in surface energy due to the creation of new free surfaces. This theory is applicable to elastic materials that fracture in a brittle fashion …
What is fracture in fracture mechanics?
• Fracture is the separation of a body into two or more pieces in response to a. static load which is applied at a temperature lower than the melting point of the material. • Fracture involves crack initiation and crack propagation.
What is flaw size?
flaw size (aCFS) is obtained when the maximum stress intensity factor for any one cycle of. the loading spectrum exceeds the fracture toughness value.
Which theory explains brittle fracture?
Which theory explains brittle fracture? Explanation: Griffith extensively studied brittle fracture. He proposed a mechanism to explain it. He did it using theory of microcracks.
What are linear elastic or Hookean materials?
A material which obeys hooke’s law is called a linear elastic or Hookean material. Hookean behaviour is also called linear elasticity.
What is isotropic linear elastic material?
A material is said to be isotropic if its properties do not vary with direction. Isotropic materials therefore have identical elastic modulus, Poisson’s ratio, coefficient of thermal expansion, thermal conductivity, etc.
What is linear elastic fracture mechanics (LEFM)?
Linear Elastic Fracture Mechanics (LEFM) is the basic theory of fracture, which was originally developed by Griffith (1921, 1924) and modified by Irwin (1957). Linear elastic fracture mechanics (LEFM) can be studied by either the near-tip stress field or the energy method.
Can linear elastic fracture mechanics be applied at the composite-adhesive interface?
The application of linear elastic fracture mechanics (LEFM) at the composite-adhesive interface requires consideration of the bimaterial properties of this crack tip. The mismatch in elastic properties is commonly expressed in terms of the Dundurs second parameter, β, under plane strain conditions ( Dundurs, 1969 ), which is given by
Can LEFM be used to calculate the fracture strength of aircraft?
The metals used in aircraft are ductile, and therefore LEFM cannot be used to calculate the fracture strength. With some modification, however, LEFM can be used to calculate the fracture stress of ductile metals. Two scientists named Orowan and Irwin modified LEFM to account for plastic flow at the crack tip.
Is Ki = KIC a valid criterion for hydraulic fracture propagation condition?
In the numerical models developed using a linear elastic fracture mechanics (LEFM) approach, a criterion that states KI = KIc, where KI is the mode I stress intensity factor (SIF), has been widely employed to determine the hydraulic fracture propagation condition 11, 12, 13.