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

Determine the forces on bar, Determine the Forces On Bar Two bars and ...

Determine the Forces On Bar Two bars and a cable are used to support a block as shown. The two bars have negligible weight and the pulley is free to rotate. The mass of the pu

Motion/movement, What are the different types of Mechanical Motions/Movemen...

What are the different types of Mechanical Motions/Movements?

Drive the expression for critical pressure ratio, Drive the expression for ...

Drive the expression for critical pressure ratio for steam nozzle and illustrate critical pressure. Air flows in a 200cm 2 duct at a velocity of 180 m/s, a pressure of 119 KPa

Compressors, How can I construct a tyre pumping machine.

How can I construct a tyre pumping machine.

What is the drilling operation, What is the Drilling operation Drilling...

What is the Drilling operation Drilling operation can only performed in vertical direction. Hence drilling hole at angle is not performed by drilling machine. It is a big drawb

Reduce system to a single force and couple, Reduce system to a single force...

Reduce system to a single force and couple: Q: A system of parallel forces is acting on rigid bar as shown in the figure given below. Reduce this system to  a single force

Hot working of metals, advantages and disadvantages of hot working of metal...

advantages and disadvantages of hot working of metals

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