Sahil Sura
Ansys Employee



Hello Naresh Jogi,
The material properties mainly affecting the results of the linear elastic static structural analyses can be the Modulus of Elasticity (which plays a key role in assessing the stiffness) and Poisson’s Ratio. The Tensile Yield Strength also plays a key role when determining the safety factor, but this does not affect the calculation of stress and deformation.
So if checked via Ansys Material Library, Structural Steel ASTM A992 has a Young’s Modulus of 2.1239e+05 MPa at 23 Degrees Celcius, while from the other sources for the same conditions, Structural Steel ASTM A 36 has a Young’s Modulus of 1.9994e+05 MPa. So if noticed the difference in Young’s Modulus, there must be a very minor deviation observed in the results.
Thus considering this the results should vary to a certain extent. These FEA algorithms are based on numerical methods and thus have limitations; accuracy can be compromised as per the application to a certain extent and thus is up to the user.

A simple hand calculation would also help in addressing the difference observed in the results, which can be a great baseline for comparison.

The solution to the problem can be -
Re-verifying the material properties from physical testing
Turning on Large Deflection to capture better plasticity effects 
Refining the mesh and checking the boundary conditions

Hope this helps!