Answer to Question #298055 in Mechanical Engineering for RAVINDER

Question

A high strength steel of yield strength: 1200 Mpa in form of wide plate contains a Semi elliptical surface crack of depth 10mm and length 100mm and located at centre of plate. The plate is subjected to tensile stress at 90° angle to crack. The plate was found to break in service in unstable manner resulting completely flat fracture surface. the size of plastic zone measured at minor crack tip just at the instant of fracture to be 0.25 mm. what could be have the fracture toughness

Answer 1

Stresses at or near a discontinuity such as a hole in a plate are higher than if the discontinuity does not exist. Elementary stress equations do not apply in stress concentrations. 

fracture toughness refers to a property which describes the ability of a material containing a crack to resist further fracture. Fracture toughness is a quantitative way of expressing a material's resistance to brittle fracture when a crack is present.