Simulating a Tensile Test?

[jzhaan55]

Is there a way to simulate a simple tensile test in autodesk inventor. Let's say I draft up a 1" x 1" x 10" bar. If I input all of the material properties such as yield strength, tensile strength, % elongation etc., is there a way that I can simulate a simple uniaxial tension test on this bar? If so, how do I set it up with the autodesk simulation engine?

Thanks a lot for the help,

Jessica

[jzhaan55]

Also, if I exceed the % elongation rating for the bar, will the bar physical break in half during the simulation?

[henderh]

The answer to your first question is Yes, and second question is No.

% elongation is not a material property for ductile or brittle materials, it is usually specified for non-linear materials like elastomers (e.g. rubber)

Since Inventor SA is a linear solver, it won't be able to simulate or display true deformations that occur after the yield point is reached.  This is when (in reality) the material plastically deforms to the point of necking, rupture and exhibiting the cup and cone fractured surfaces for ductile materials, or the non cup and cone for brittle fracture.

There is more information about the assumptions of linear stress analysis here:  http://usa.autodesk.com/adsk/servlet/ps/dl/item?siteID=123112&id=7263238&linkID=9242018

  If you require a non-linear stress analysis, we recommend using Autodesk Simulation Mechancial: http://usa.autodesk.com/adsk/servlet/pc/index?siteID=123112&id=13773836

Hope this helps.  Please let us know if you have any additional questions, comments or suggestions.

Best regards, -Hugh

[Edit: added some tidbits]

[henderh]

Hi Jessica,

  Were my replies helpful at all?  Another reason that this could be challenging for any FEA software is that what you are asking is that the package be able to include the microscopic dislocations of the materials 'crystal lattice'.  This is beyond what Inventor can do.

  Also, since the geometry is plastically deforming and strain-hardening in real-life, it may be necessary to create a new mesh based on the changing shape of the geometry.  There are only a few FEA packages I know of that can support a constantly changing geometry / mesh analysis.

Thanks, -Hugh

[alihillaldam]

Hi there,

Can you please explain how you simulate a simple tensile stress test?

Cheers

Ali

[henderh]

Hi Ali,

  Attached you'll find and R2013 part that has a typical tensile test applied to a 'dog-bone' specimen.  Since Inventor's Stress Analysis uses only the linear portion of the stress-strain curve, any results beyond yield are not applicable for ductile materials.

  These are the basic steps:

1)  Fix either the bottom face, or split the cylindrical face to create a smaller face that the "gripper" would grab on to in real-life for application of the fixed constraint

2)  Similar to 1) add a force to a face that would simulate the tensile load.

3)  Run the Simulate command

  Open the convergence plot and see that the result has converged below 1% without having to adjust any convergence settings.

Hope this helps! -Hugh

[alihillaldam]

Thanks for your reply.