Linearity and nonlinearity

- December 13, 2019 at 4:04 am
  
  danilo98
  Subscriber
  
  Hi guys.
  
  I have two questions.
  
  The first is what is the difference between a linear and a nonlinear analysis in workbench and how can I know which of them I am using.
  
  And the second is, how workbench uses the Young`s modulus in order to calculate the stresses.
  
  Thank you for your help.
- December 18, 2019 at 4:23 pm
  
  peteroznewman
  Subscriber
  
  Hi Danilo98,
  
  There are three kinds of nonlinearity in Structural models.
  
  Geometric is when there are Large Deflections. You turn that on under Analysis Settings.
  
  Material is under Engineering Data where you can add things like Plasticity or Hyperelastic models. If the only property is from the Linear Elastic category or Physical Properties like Density, then you have a Linear material model.
  
  Contact is added under the Connections folder. The linear contacts are Bonded and No Separation. The nonlinear contacts are Rough, Frictionless and Frictional.
  
  The FEA model uses nodes to track deformation (displacement). For a 1D linear element like a LINK, there are only two nodes. The change in length of the element is divided by the element length to compute Engineering (linear) Strain. Stress = Strain*E where E = Young's Modulus.