Define fatigue - materials, Civil Engineering

Assignment Help:

Define Fatigue - Materials

The normative view of the stress/strain is found in the example of the paper clip wire experiment. Take a paper clip wire and try to break it by pulling on it by hand. You are unable to break it because you need to exceed the ultimate stress of the material. Bend a paper clip between your fingers and the following is observed: when the wire rebounds to its original shape the proportional/elastic limit is observed; bend it farther to a point where the wire is permanently deformed, the yield point is observed; and, when the wire is bent one way then the other a few times, the wire breaks easily. The phenomenon is known as fatigue.

1968_Define fatigue - materials.png

All materials have microcracks. The cracks are not critical and are averaged as ultimate strength for the bulk material in a tension test. However, when the material is subjected to cyclic loading, the microcracks can grow until some of the cracks reach critical length, at which time the material breaks. The stress value at cyclic loading is significantly lower than ultimate stress of the material. Failure due to cyclic loading at stress levels significantly lower than the static ultimate stress is called fatigue. All engineered systems account for fatigue failure. At low levels of stress the failure may occur at millions or billions of cycles. Endurance tests determine the cyclic loadings and fatigue strength.

 


Related Discussions:- Define fatigue - materials

Properties of stones, Properties of Stones The following properties of ...

Properties of Stones The following properties of the stones should betake into account before choosing them for engineering works: Structure: The structure of the stone ca

Ecology, subdivisions of ecology

subdivisions of ecology

Engineering indicators in case of multi speed restriction, Multi Speed Rest...

Multi Speed Restriction (i.e. existence of two or more than two speed restrictions in continuation) When work of deep screening or sleeper renewal is in progress, there is situ

Example of magnetic dip, Example : Line AB was drawn with a magnetic ...

Example : Line AB was drawn with a magnetic bearing of 136° 45′ while the magnetic declination was 2° 30′ east In an old map. If magnetic declination is 3° 30′ west to what m

Describe about the baur-leonhardt system, Describe about the Baur-Leonhardt...

Describe about the Baur-Leonhardt system The Baur-Leonhardt system is included in the third type of anchorages which work under the principle of looping tendon wires at the en

What is the cost of phoenix activity, Q. What is the cost of phoenix activi...

Q. What is the cost of phoenix activity? Phoenix activity has a range of impacts on the Australian economy. Employees lose entitlements when phoenix activity has occurred and w

#title.steel desogn, Tension memebers example for a two channel connected t...

Tension memebers example for a two channel connected to a gusset .find the tensile capacity

Soil Mechanics, Good evening. I have two homework projects from the Soil Me...

Good evening. I have two homework projects from the Soil Mechanics. I am interesting if anybody can solve them.

Geofabric strengthening of perth soils, I need technical assistance. The pr...

I need technical assistance. The project is incomplete. I need someone to proofread it. Do you have someone who know Plaxis, Slope/W and Flac?. Can you arrange a case study for Geo

Major bridge and important bridge, Major bridge - Major bridge is one of wh...

Major bridge - Major bridge is one of which has a total linear waterway of 18 m or more for multiple span and total linear water way of 12 m or more for single span. Important b

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