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COMPONENT FAILURE MUSEUM

The main sections of the museum are listed below;

Metal Fatigue
Manufacturing Faults
Bicycle Components
Corrosion
Polymers
Composite Materials

Tools of the trade, some ways to investigate problems;
Photoelasticity
Dye penetrant testing

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of materials engineering terms

 

Lorry steering arm failure

 

Click on pictures below for full size image in new window. 

 

 

 

1.  Steering arms

2.  Steering arm crack

 3. Steering arm surface

 A batch of 12 forged steel lorry steering arms showed fatigue cracking about 140mm from one end. Here the polished component in the centre picture shows a typical crack. The manufacturers had omitted the final heat treatment that left the steel's yield stress 30% lower than specified.

Image1 shows the steering arms.
Image2 shows a close up of the fatigue crack in one arm.
Image3 shows the classic fatigue fracture surface with 'beach' marks and final rough fracture.

Return to metal fatigue section

ED; AG 17/12/01

 
 
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