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 is pressure testing, Q. What is Pressure Testing? Pressure test sh...

Q. What is Pressure Testing? Pressure test shall be performed after completion of all welds and the PWHT of the boiler. Prior to final inspection and pressure test, the insi

Design for dynamic and wear loads, A gear drive is needed to transmit a max...

A gear drive is needed to transmit a maximum power of 22.5KW. The velocity ratio is 1:2 and r.p.m. of the pinion is 200. The centre distance between the shafts can be taken as 600m

Molding methods according to the method of making a mold, Q. Molding method...

Q. Molding methods according to the method of making a mold? Following are the molding methods according to the method of mold making: • Open mold method: the method is su

Thermodynamics, klfjaljf jlas jfklsj flasj; flkjs fklja sklfj ak;lsfj lkajs...

klfjaljf jlas jfklsj flasj; flkjs fklja sklfj ak;lsfj lkajsf; kljas fkl;ajsd flk;jads fklasjdfl kjkl fjdaskl fjdsklafj ksad ,ma,v. askjlvj kljdfiojajofj adjfkldsj fkljasdf lkjads;

Evaluate total extraction, Evaluate total extraction: The steel tie r...

Evaluate total extraction: The steel tie rod 50mm in diameter and 2.5m long is subjected to pull of 100 KN . To what length the rod must be bored centrally so that total ext

Home home, why 4R kinematic chain do not form different mechanisms?

why 4R kinematic chain do not form different mechanisms?

Different laws of perfect gas, (a) What is an ideal gas ? How does it diffe...

(a) What is an ideal gas ? How does it differ from perfect gas ? Write the different laws of perfect gas. (b) The pressure in a car tyre was checked at 15 o C temp. and reading

Grinding and brushing, Grinding & Brushing: Grinding is process there ...

Grinding & Brushing: Grinding is process there has an abrasive wheel that rotating at certain speed to smooth a surface or to give an even finish on material. In this Blade pr

Coplanar and non-coplanar forces, Coplanar and Non-Coplanar Forces: In...

Coplanar and Non-Coplanar Forces: In this unit, you have learnt to identify the different systems of forces. You have also learnt the many techniques of adding the forces to g

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