Learning Forum

[saransh.verma2810]

I am conducting a TIG welding analysis to calculate residual stress.
first i calculated Temperature in transient thermal using convection, radiation and moving heat source.
Then this temperature was used a input in transient structural to calculate residual stress using fixed support as boundary condition.

The graph of stress only shows tensile stress but not compressive stress.But residual stress do have compressive stress

How can i correct it

Please Help me

[dlooman]

Residual stress requires path-dependent nonlinear material properties (plasticity) and the elevated stress free temperature of the molten material.  The effect of molten material cooling is almost entirely tensile, so your result doesn't surprise me too much.  Are you plotting a signed quantity like SX or an unsigned quantity like SEQV?

[saransh.verma2810]

I am plotting Equivalent (von-Mises) Stress vs length 

and the properties of materials are as followed

Material

[dlooman]

Since equivalent stress is unsigned you may be incorrectly assuming the stress is tensile.  You can't identify whether the stress is tensile or compressive with SEQV.  The material properties are good, but you still need to specify an elevated stress-free temperature for regions where the material has become molten.

[saransh.verma2810]

Where can I add elevated stress free temperature where material has become motlen like where can i find it in engineering data 
and which stress type should use to get desired results  

[dlooman]

In the details for the body you can specify the "Reference Temperature."  A "Normal Stress" like SX, SY or SZ would be signed.

[saransh.verma2810]

I am still not getting it like i should define reference temperature by body so what should be value of reference temperauture

and now while taking normal stress the stress is entirely negative 

[dlooman]

It's not an exact science, but a temperature at which the molten material begins to have some strength.  If you don't taken into account the elevated reference temperature you are just applying a thermal expansion load which will naturally produce compression.  Are both ends of the pipe fixed in real life?

[saransh.verma2810]

How can i take elevated reference temperature like from where should i add it 
and the ends of pip are fixed

 

[saransh.verma2810]

I tried giving it a elevated reference temperature where material has become motlen
now the stress have become more high 

Please Help me