Hi,

 

I am running Linear static FEA in Solidworks simulation for an assembly in which all the parts are made up of steel.

I usually consider only Von mises stresses as failure criterion for this assembly. But now i want to know the maximum tensile and compressive stress in the assembly and its location.

 

Please let me know on how to get the values of maximum tensile and compressive stresses or plots for tensile and compressive stress.

 

Thanks in advance,

Sandeep


Categories: Simulation

Comments
Last comment By: Eric Christison   Tue, 17 Apr 2018 14:04:34 GMT
Re: Stress plots for Tensile and Compressive stress in a assembly.

any reason why you wouldn't plot P1 and look at the extremes?

By: Jared Conway  Thu, 24 Oct 2013 05:25:14 GMT
Re: Stress plots for Tensile and Compressive stress in a assembly.

Hi Jared,

 

As per your suggestion, i have plotted 1st principal stress. I have further queries regarding this. Kindly let me know your comments.

 

1. Does the extreme values in the plot indicate max tensile and compressive stress?

2. When do we plot 2nd and 3rd Principal stress and what does these plots signify?

3. What is the meaning when positive extreme of P1 crosses Max value in Von mises. Which is the stress to be considered for ductile material to predict failure?

 

P.S: I am running FEA on an assembly where the componants are of ductile material (SS) .

By: Sandeep S  Thu, 24 Oct 2013 17:09:19 GMT
Re: Stress plots for Tensile and Compressive stress in a assembly.

hi sandeep, let's dig deeper into your question. what are you trying to determine in your model? what is your failure criteria?

 

do you have expected results that you're comparing to simulation? are you concerned that the results you're seeing aren't what you're expected?

 

the reason i ask this is because i think there are short and long answers to your questions but are dependent on your goals and concerns.

By: Jared Conway  Thu, 24 Oct 2013 23:12:22 GMT
Re: Stress plots for Tensile and Compressive stress in a assembly.

Hi Jared,

 

Failure criteria that is considered is that the parts (SS- ductile) in the assembly should not cross half the value of yield strength (FOS = 2) in tension and bending. I am not so much worried about stresses in Compression. Hence i wanted to know if the High value of stress that i see in Von mises plot ( almost 2 times of Yield strength) is Tensile or compressive.

 

It'll be helpful if you can answer the following queries

 

1. Does the extreme values in the P1 plot indicate max tensile and compressive stress?

2. When do we plot 2nd and 3rd Principal stress and what does these plots signify?

3. What is the meaning when positive extreme of P1(Tensile) crosses Max value in Von mises. Which is the stress to be considered for ductile material to predict failure?

 

Also i do not have any expected results or Hand calulations to compare with the FEA results. I'll have to optimize (stress optimization) the assembly purely based on the FEA results obtained for Solidworks simulation.

By: Sandeep S  Fri, 25 Oct 2013 14:30:33 GMT
Re: Stress plots for Tensile and Compressive stress in a assembly.

Those questions may be irrelevant if the high stress is in the region of a singularity. I would suggest starting there. The rest you can come back to.

By: Jared Conway  Fri, 25 Oct 2013 14:46:54 GMT
Re: Stress plots for Tensile and Compressive stress in a assembly.

The high stresses that i see in the Von mises plot is spread over a continuous finite region. and is not in the region of singularity.

By: Sandeep S  Fri, 25 Oct 2013 14:51:11 GMT
Re: Stress plots for Tensile and Compressive stress in a assembly.

sounds like a redesign necessary

By: Jared Conway  Fri, 25 Oct 2013 14:57:28 GMT
Re: Stress plots for Tensile and Compressive stress in a assembly.

I will need to redesign if the stress are tensile. Hence i want to know more about principal stress plot to know if the stresses are tensile or compressive.

 

1. Does the extreme values in the P1 plot indicate max tensile and compressive stress?

2. When do we plot 2nd and 3rd Principal stress and what does these plots signify?

3. What is the meaning when positive extreme of P1(Tensile) crosses Max value in Von mises. Which is the stress to be considered for ductile material to predict failure?

By: Sandeep S  Fri, 25 Oct 2013 15:13:06 GMT
Re: Stress plots for Tensile and Compressive stress in a assembly.

Hi,

 

Can someone through some light into this Unanswered query please.....

How to extract tensile & compressive stresses ?

By: Ajay S.  Fri, 12 Aug 2016 03:35:26 GMT
Re: Stress plots for Tensile and Compressive stress in a assembly.

Hey Ajay,

 

I think the answer is not trivial so it's hard to find a concrete answer on what to do. I'm reading about this right now and I think in short this is what you do.

 

Max tensile stress = max of 1st principal stress

Max compressive stress = minimum of the 3rd principal stress.

 

Other things to keep in mind

     You can also look at the stresses in the X,Y,Z planes which is useful if your stress is in those directions.

     You should always increase your mesh size to check that your results are converging

     Check that the stress values do not occur at a singularity

By: John Miko  Fri, 06 Apr 2018 13:46:07 GMT
Re: Stress plots for Tensile and Compressive stress in a assembly.

If the principle stress is positive, it's tensile. Negative is compressive.

As a sanity check run an animation of how the part deforms under load and you can figure out for yourself whether a surface is being compressed or stretched. Another sanity check it check the strains, again, positive tensile and negative compressive.

By: Eric Christison  Tue, 17 Apr 2018 14:04:34 GMT
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