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

Explain rate pressure product, Q. Explain Rate Pressure Product? The sy...

Q. Explain Rate Pressure Product? The systolic blood pressure is multiplied by the heart rate to provide the double product or modified fusion time index. On presence of an obs

Thermodynamics, Convert the following readings of pressure to KPa absolute,...

Convert the following readings of pressure to KPa absolute, assuming that the barometer reads 760mm Hg: (a) 100 psig, (b) 8in. Hg vacuum, and (c) 76in Hg gage.

Simply supported beam, Simply Supported Beam: Simply Supported Beam: ...

Simply Supported Beam: Simply Supported Beam: The beam on which both ends are supported, either by point load or hinged or roller support.

Explain importance of continuum in thermodynamics, What is the importance o...

What is the importance of the concept of continuum in engineering thermodynamics. Sol: Tough the simplification of matter into atoms, electrons, molecules, and so on, is very c

Air-gas cross-limiting and air-gas ratio control, Q. Air-Gas Cross-Limiting...

Q. Air-Gas Cross-Limiting and Air-Gas Ratio Control? The Steam Generator firing demand signal is directed to two discrete signal selectors. A low signal selector ensures that

IDE101, Polygon law of forces

Polygon law of forces

Illustrates the effect of wall movement on earth pressure, Illustrates abou...

Illustrates about the effect of wall movement on earth pressure? Effect of wall movement on earth pressure About fifty years ago Terzaghi conducted a series of tests on larg

Working of engine lubrication system , Working of Engine Lubrication System...

Working of Engine Lubrication System: The oil flows from oil pump into the distribution chamber, where it is divided into two parts. One part enters into the right crankcase cove

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