Tensile Test With Extensometer Shimadzu Autograph Universal Testing Machine

[@TGUGCL]

great video. I was wondering why did the sample broke on the top and not towards the middle?

[@MechanicalTesting]

Thanks for asking . This is a very generic doubt many customers asked. Why the samples are not broken in the middle. Sample need not to be broken always from the middle. It can break anywhere in the Gauge length region .Up on reaching the ultimate load , the weakest point in the GL Region ( Any where ) , started nodding and eventually the sample break in the region where the nod devoloped . . Some times this nod develop in the middle , but not necessary that it always happens to be in the middle . . i hope the answer is clear . If you have any doubt , please feel free to ask

[@TGUGCL]

@Mechanical Testing I understand, it makes sense that the sample breaks where the "nod" creates since the lower cross section area will result in a higher Stress. My question is why the "nod" devellops there in the first place. Does it has something to do with the imperfections or dislocations in the crystal lattice in that particular area? Can we say that since the nod develloped there (anywhere) then its due to the fact that they were some imperfections present at that location?

[@Johnssj10]

@@TGUGCL that is correct indeed, alternatively the user might choose to artificially create a small surface imperfection which will create localized stress and will make it possible to measure strain after necking has occurred while using proper equipment. If such an experimental method is followed, the size of the imperfection needs to be calculated and applied with great accuracy otherwise the triaxiality value in such kind of loading conditions might change considerably.

[@rohtashrawat7238]

Sir can you tell me something about connection of extensometer

[@rohtashrawat7238]

How to connect it with PLC

[@MechanicalTesting]

Hi Rohtash , Can you be more specific for me to answer clearly . Extensometers are connected for yield point measurement , once the sample reaches the yield point ,we remove the extensometer and the test continues until sample break .

[@MechanicalTesting]

@@rohtashrawat7238 Extensometer is directly connected to to the Machine . . All UTM Machines have provision for connecting extenal sensors ( Like extensometer , Width Sensors , Strain Gauges etc etc )

[@zainsaeed147]

@@MechanicalTesting May i know in case we need to know the post yeild stress-strain behavior then what instrument we should rely on. As the strain gauges also worked until yielding point.

[@jheelpatel8650]

Why we rwmove extensometer at 1000micron mark

[@MechanicalTesting]

Hi Jheel , Extensometer are very delicate accessory and my damage when the specimen break . Thats why we are removing extensometer after yield point ( Extensometer is mainly for getting elastic data and yield data and industry standard allows you to remove the extensometer after yield point ) . But industry have also automatic extensometer which you can keep until break . But will be more expensive than conventional type extensometer

[@WISEMANYT]

@@MechanicalTesting If we are removing extensometer then how strain is calculated after yield point?