Destructive and Non Destructive Testing

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  • Topic: Nondestructive testing, Materials science, Magnetic-particle inspection
  • Pages : 8 (1911 words )
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  • Published : December 2, 2012
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Destructive and Non-destructive
Testing for Maintenance Applications

Why use testing?
* Make best use of limited budgets
• Repair vs. replace
• Increase load limits
* Preserve our infrastructure
• Economics
• Historic structures
* Make sound judgments to repair or replace
* Increase level of confidence / decrease uncertainty
* Increase overall safety

Destructive Testing
Destructive testing (DT) includes methods where your material is broken down in order to determine mechanical properties, such as strength, toughness and hardness. In practice it means, for example, finding out if the quality of a weld is good enough to withstand extreme pressure or to verify the properties of a material. Destructive testing is most suitable, and economic, for objects which will be mass produced, as the cost of destroying a small number of specimens is negligible. It is usually not economical to do destructive testing where only one or very few items are to be produced (for example, in the case of a building). These properties can’t be examined with non-destructive methods, as specimens of the material must be extracted. Destructive testing is generally most suitable and economic for mass produced objects, as the cost of destroying a small number of pieces is negligible. The samples are put under different loads and stress. That way we can analyze in which point your material eventually gives up and cracks. The results gained are then compared to regulations and/or quality guidelines.

Destructive tests are best when used together with our non-destructive methods: this combination gives the best information on materials and welds. Non-destructive tests show if cracks, corrosion or other faults exist. Destructive tests in turn indicate how and when the objects are in danger of breaking down or failing.

Benefits of Destructive Testing (DT)
* Verifies properties of a material
* Determines quality of welds
* Helps you to reduce failures, accidents and costs
* Ensures compliance with regulations

Types of Destructive Testing:
Stress testing
 is a form of testing that is used to determine the stability of a given system or entity. It involves testing beyond normal operational capacity, often to a breaking point, in order to observe the results. Stress testing may have a more specific meaning in certain industries, such as fatigue testing for materials.

Crash test 
is a form of destructive testing usually performed in order to ensure safe design standards in crashworthinessand crash compatibility for various modes of transportation or related systems and components.

Types of Crash Test:
* Frontal-impact tests: which is what most people initially think of when asked about a crash test. These are usually impacts upon a solid concrete wall at a specified speed, but can also be vehicle-vehicle tests.

* Offset tests: in which only part of the front of the car impacts with a barrier (vehicle). These are important, as impact forces(approximately) remain the same as with a frontal impact test, but a smaller fraction of the car is required to absorb all of the force. 

* Side-impact tests: these forms of accidents have a very significant likelihood of fatality, as cars do not have a significant crumple zone to absorb the impact forces before an occupant is injured.

* Roll-over tests: which tests a car's ability (specifically the pillars holding the roof) to support itself in a dynamic impact. More recently dynamic rollover tests have been proposed as opposed to static crush testing.

* Roadside hardware crash tests: are used to ensure crash barriers and crash cushions will protect vehicle occupants from roadside hazards, and also to ensure that guard rails, sign posts, light poles and similar appurtenances do not pose an undue hazard to vehicle occupants.

* Old versus new: Often an old and big car against a small and new car, or two different generations of the...
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