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 bending stress, The cantilevered beam made from the Z section...

The cantilevered beam made from the Z section is subjected to the two loadings as shown. (a)  Determine and show the orientation of the neutral axis on the cross section (angle

Define the methods of constructive solid-geometry, Constructive Solid-Geome...

Constructive Solid-Geometry Methods (CSG) Constructive models represent a solid as a combination of primitive solids. This modeling technique combine the volumes occupied by ov

Fluid Mechanics, Please help me solve the following problem. Steam is thro...

Please help me solve the following problem. Steam is throttled from a pressure of 700kPa to 100kPa and a temp. of 100 degrees Celsius. Determine the dryness factor of the steam

Withworth quick return mechanism, its definition, principle, explanation, a...

its definition, principle, explanation, application, and a diagram

Question.., Two concentric perforared plates are seperated by a 200mm laund...

Two concentric perforared plates are seperated by a 200mm launder and form the flow exit for a clarifier (figure 1). The inlet water flow of 1200 mcubed/hour into the clarifier is

Use roller support - steel trusses of bridges, Use roller support - steel t...

Use roller support - steel trusses of bridges: Explain, why do we use roller support in case of steel trusses of bridges? Sol. : In the bridges most of time external f

Illustrate boot-strap air evaporative cooling system, Why is it required of...

Why is it required of cooling the aeroplane ? Illustrate Boot-Strap Air Evaporative cooling system with neat sketch and T-S diagram.

Polythionic Acid Stress Corrosion Cracking, In Naphtha Hydrotreating Unit, ...

In Naphtha Hydrotreating Unit, does feed/effluent heat exchangers require passivation to avoid polythionic acid stress corrosion cracking.

Rope drive, Rope drive: What do you mean by the term rope drive? ...

Rope drive: What do you mean by the term rope drive? Sol: The ropes are circular in section. Rope-drive is mostly used when distance between the driving shaft and drive

Maximum shear stress and angle of twist, Maximum shear stress and angle of ...

Maximum shear stress and angle of twist: Torques are applied on the shaft as illustrated in Figure. Discover in which portion of the shaft, maximum shear stress & angle of twi

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