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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

Glossary
of materials engineering terms

 

Polymer failures

Leaking car cooling water system.

Click on pictures below for full size image.
Click on green text for explanation of term or see glossary.

 

Many car engine components are now made as thermoplastic injection mouldings. This manifold held temperature sensors in the coolant system close to the cylinder head and began leaking after 5 years service. The housing was secured by two bolts which compressed an 'O' ring elastomer seal. This reduces the need for accurately matched faces when an ordinary gasket is used.

Unfortunately stress relaxation by creep of the 'O' ring had occurred and the original section was now quite flat and offered no resistance to the clamping bolts. This caused the seal to be inadequate against the pressurised water and a leak occurred.

A simple replacement of the 'O' ring gave a cheap repair that should last another 5 years.

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ed: AG 17/12/01

 
 
© 2005 Materials Engineering - Page last modified 18-Dec-2007