Calculate the critical crack length, Mechanical Engineering

Assignment Help:

Calculate the critical crack length:

A wide plate of mild steel is subjected to uniform tensile load causing a stress of 100 MPa. Calculate the critical crack length in the centre of plate which when reached will cause the plate to fracture, if fracture toughness of mild steel is 1340 N / mm2

Solution

The crack will become unstable in the centre of the plate, i.e. the fracture will occur when the crack has attained a critical length (say ac) under given stress ? which remains constant. At this moment KI → KIC.

KI for a large plate with central crack of length 2a is by Eq.

1433_Calculate the critical crack length.png

and hence

211_Calculate the critical crack length1.png

or        

629_Calculate the critical crack length2.png

∴          2ac = 114.3 mm

[This example explains how the knowledge of fracture toughness of material and KI of a crack can be used to calculate the length of a crack which must not be permitted to exist. If the cause of crack extension may not be controlled, the only thing left to designer is to calculate critical length in advance. Then the crack length would have to be monitored throughout the life of the structure and as soon as it approaches the critical value, the structure should be discarded to avoid sudden fracture or other measures be taken by which either KI is reduced to KIC is improved.]


Related Discussions:- Calculate the critical crack length

What are methods used in rating for time study, a)What are methods used in ...

a)What are methods used in rating for time study. Illustrate them. b) Write down principles of motion economy.

Belt drive, how will u designate a v belt

how will u designate a v belt

Foil butt seam welding, Foil Butt Seam Welding This is a modification o...

Foil Butt Seam Welding This is a modification of seam welding, in which thin narrow strips of metal arc introduced between one or both of the circular electrodes and the work p

Tolerance analysis, Tolerance Analysis This discusses the importance o...

Tolerance Analysis This discusses the importance of assigning tolerances to the dimensions. Tolerance analysis is the process of assigning suitable tolerances. Proper assignme

Example of change of enthalpy, Example of change of enthalpy: Q 0.5...

Example of change of enthalpy: Q 0.5kg/s of a fluid flows in steady state process. The properties of fluid at the entrance are measured as p 1 = 1.4bar, density = 2.5k

CNC Machining, how to determine proper the depth of cut for the tool if the...

how to determine proper the depth of cut for the tool if the drill is made of HSS and the work piece is made of alluminume alloy?

Relative velocity in mechanism, how can I determine the relative velocity ...

how can I determine the relative velocity in mechanism

Shielding gas, SHIELDING GAS The primary function of the shielding gas ...

SHIELDING GAS The primary function of the shielding gas is to exclude the atmospheric air from the arc zone. However, the shielding gas has significant influence on the arc cha

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd