response of metals

[ginsoakedboy]

How long does a material (say, steel) take to deflect to a corresponding magnitude of strain when acted upon by a certain stress? In essence, how fast do metals react (deform) under forces acting on them?

 

[metengr]

Well, if you are familar with tensile testing of ferrous metals the answer is obvious. Strain is what it is, a dimensionless quantity that represents deformation. During a tensile test as the load is applied using a specified strain rate per a standard test method, the strain response and load are measured instantaneously.

 

[CoryPad]

If you are interested in rate effects, then consider that strain waves travel through solids at the speed of sound.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[cloa]

I agree general magnitude of the speed of deformation but it would be only the speed of sound in the elastic region. When the metal plastic deforms, it would occur slightly slower as the metal forms dislocations (imperfections in the microstructure). It takes some time to form these and when you form lots of them, the stress waves are slowed as they drive these dislocations through the structure.