Non linear simulations using static structural analysis

- March 23, 2020 at 12:40 am
  
  tpz1
  Subscriber
  
  Hello!
  
  I am trying to simulate compression tests with polymer samples. I did a static structural analysis but I manage to have the strain-stress curve with only the linear curve.
  
  What could I do in order to have both the linear and the non-linear curves? If I perfom tensile tests, will I have enough data to characterize the material in ANSYS?
  
  Thank you for your help
- March 24, 2020 at 3:32 pm
  
  Sai Deogekar
  Ansys Employee
  
  Hello,
  
  What kind of material did you define for your sample? If it was linear elastic, it will only give you a linear stress-strain curve. So first make sure that the material is defined correctly. Secondly, if your sample undergoes large deformation (i.e. has large strains or rotation), make sure the Large Deflection option is On.
  
  About your second question: if the material behaves in an identical manner under both tensile and compressive loads, then you can use the data from tensile tests to characterize the material. If the material shows different behaviors in compression and tension, then you will need separate data under compressive loads.
  
  Hope this helps,
  
  Sai
- March 25, 2020 at 5:46 am
  
  tpz1
  Subscriber
  
  Hello,
  
  Thank you for your help!
  
  At the moment, I use nonlinear materials available in the engineering data. Then, once I will perform tensile and/or compression testings (with polymers), I plan to define multilinear isotropic hardening. Is it enough to properly define a nonlinear material in the software?
  
  I ran a simulation (using Structural Steel NL) and I inserted a chart with total strain and equivalent stress and it is still linear… Do you have any idea what the problem is? My goal would be to display the strain stress curve with both elastic and plastic deformations.
  
  Thank you