Theories of failure and tensile testing

In summary, the conversation discussed why theories of failure are based on 1-D tensile testing and why 2-D or 3-D testing is not used. The question was posed if there are any situations where these additional types of testing would be beneficial. The conversation also mentioned recent work on why bent spaghetti shatters instead of just snapping. The answer to the question about 2-D and 3-D failure theories lies in the study of fatigue, where shape can concentrate flexure damage and initiate failure.
  • #1
Death eater
22
1
Why theories of failure have been developed from 1-D tensile testing. Why can't we go 2-D testing or 3-D testing?
 
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  • #2
Can you give any examples of where these additional types of testing would be beneficial?
 
  • #3
There was recent work on why bent spaghetti shatters rather than 'just' snaps.
https://phys.org/news/2018-08-mathematicians-age-old-spaghetti-mystery.html
IIRC, they found that applying torsion to um, pre-stress it made it snap clean when bent...

Per OP's query, I think the answer lies in the study of 'fatigue', where unfortunate shape concentrates flexure damage to initiate failure. Once that begins, a simpler model may approximate...
 
  • #4
JBA said:
Can you give any examples of where these additional types of testing would be beneficial?
I am just asking why we are using theories of failure to determine 2-D faliure stresses why not practically test it as it is done with 1-D
 
  • #5
Nik_2213 said:
There was recent work on why bent spaghetti shatters rather than 'just' snaps.
https://phys.org/news/2018-08-mathematicians-age-old-spaghetti-mystery.html
IIRC, they found that applying torsion to um, pre-stress it made it snap clean when bent...

Per OP's query, I think the answer lies in the study of 'fatigue', where unfortunate shape concentrates flexure damage to initiate failure. Once that begins, a simpler model may approximate...
I have a just simple question why theories of faliure was developed for 2-D and 3-D failure??
 

FAQ: Theories of failure and tensile testing

What is the purpose of a tensile test?

The purpose of a tensile test is to determine the mechanical properties of a material, specifically its ability to withstand tension or stretching forces. This allows for the evaluation of a material's strength, ductility, and elasticity.

What is the difference between a ductile and brittle material?

A ductile material is able to undergo significant deformation before failing, while a brittle material will fail suddenly and without warning when subjected to stress. Ductile materials have a higher ability to absorb energy and are more commonly used in structural applications.

What are the main types of failure that can occur in a material?

The main types of failure in a material are tensile, compressive, shear, and fatigue. Tensile failure occurs when a material is pulled apart, compressive failure occurs when a material is crushed, shear failure occurs when a material is subjected to parallel forces in opposite directions, and fatigue failure occurs when a material is subjected to repeated cyclic loading.

How do different theories of failure explain material failure?

Different theories of failure, such as the maximum normal stress theory, maximum shear stress theory, and maximum strain energy theory, provide mathematical models that predict when a material will fail under different types of loading. These theories take into account different factors such as stress levels, material properties, and loading conditions to determine the point at which a material will fail.

What factors can affect the results of a tensile test?

The results of a tensile test can be affected by factors such as the speed of loading, temperature, and the presence of defects or imperfections in the material. The dimensions and shape of the test specimen can also impact the results. It is important to carefully control these factors in order to obtain accurate and reliable results from a tensile test.

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