# Measuring Ultimate Tensile Strenght (UTS)

#1

Welcome!

I would like to ask that is it possible with SimScale to measure UTS of different materials besides of tension forces?

I would like to import a custom CAD volume to apply two equal ,external forces (N/mm2, Pa) on the two edges and then simulate until the σ equals the UTS for a certain material.

Would be also good to somehow calculate the UTS of the given paramters by SimScale.

#2

The UTS, ultimate tensile stregnth, is the stress at which a material fails. It is a material property which you can find by looking online e.g. MatWeb. When simulating forces on an object the simulation gives you (among other things) the applied stress which you must then compare to the UTS to make sure they are below the UTS. Remember that the ultimate strength of a material is different depending on if the force is tensile, compressive or torsional. You also need to make sure your stress does not reach yield stress which is the threshold for plastic deformation rather than total failure. With ductile materials like steel its ok for some local plastic deformation but for brittle materials like ceramic its unaceptable.

#3

Thanks for the feedback. I described my problem wrong, sorry.

I have to create a stress test for a custom CAD model. I have to calculate the maximum strength, after I make random dislocations in the inner region of the object.

Say, there is an H-shaped material to analyze. If we shrink the transverse section of it from 10 cm2 to 5 cm2 OR remove some inner region of it OR create a big hole in it, what is the new (deformed, reshaped) object’s maximum force withstand. It is clear, that if shrink it, we have to do a reduced force value to broke it.

This is my practice, I have to calculate the new maximum force that it can withstand without destroying it.

Is it possible in SimScale or via any framework?

#4

I guess the term you are referring to is ‘Maximum Stress’ not ‘Strength’. Strength is the property of the material and is constant irrespective of the cross section of the part.

So, here you can determine if your structure is able to withstand the applied force by dividing Proof strength of the material by calculated Von-Mises-Stress. There you will get Factor of safety for the particular case.

Regards,
Rajan

#5

In addition to what @rajan19us said you can also show the overload of a structure, a small instruction from my colleague Richard (@rszoeke) can be found here: Show overload of a structure. Please note that the calculator filter is not available in the workbench but this approach can be used in offline Paraview - the principle stays the same.

Best,

Jousef

#6

Thanks for the feedback!

Yeah, I meant Maximum Stress, not Strenght, my bad.

So recently I had an update what I have to do. I have to create a True Stress-True Strain diagram on an object, which is structurally intact 100%. Then compare it to the same object’s diagram, but instead make one or more cuts on its side.

So I have to make defections in the object. Compare the “perfect” and “defected” object TrueStress-True Strain diagram.

Do I have to measure von Mises Stress for it? Sorry for my incompetence, just learning CFD and solid analysis for two weeks.

Thanks for helping.

#7

#8

Stress exsists in different directions. Think of the von mises stress as the 3D stress magnitide. The truth is slightly more complex than that but its the easiest way to think about it.

#9

Hi @znovak!

No worries! I would then advise you to visit the SimScale Academy in order to learn more about the basics of FEM as well as CFD. Please note that the platform version used in the training is not up-to-date so if you have any questions regarding that, please just put your questions and thoughts into that section: https://www.simscale.com/forum/c/simscale-academy

Cheers!

Jousef