Linear or Nonlinear?
Linear or Nonlinear?
For many designers, it might not be clear when it makes sense to use a nonlinear solver versus a linear solver. The truth is ALL studies can be run using nonlinear. The reason we don’t always use it is because it takes several times longer to solve. Many times, linear static will provide valid results and solves very quickly.
So, what are the situations where linear static studies are a good fit? Here are a few reasons to use linear.
Response is proportional to the applied loads
- If you double the load, deformation also gets doubled
- If you remove the load, model has no deformation
Material is linearly elastic
- The part returns to its original shape if the loads are removed (no permanent deformation)
Loads are static
- Loads are applied slowly and gradually. Rapidly-applied loads cause additional displacements, strains, and stresses
So, what are the situations where linear static studies are a good fit? Here are a few reasons to use Nonlinear.
Analyze plastic and rubber products- Material Non-linearity
- Deformation beyond yield
- Does not return to initial shape when applied loads are removed
Simulate large deflection effects- Geometry Non-linearity
- Load and deflection relationship is no longer a straight-line
- Capture change in stiffness as parts deform (like a guitar string)
Contact analysis (Pushing, Sliding, changing contacts)- Contact Non-linearity
- Observe change in loaded area between parts under load
- Calculate contact/reaction force
- Material strength variation with temperature change for Thermoplastic products
- Capture product instability due to complex buckling or collapse
Hopefully this has been enlightening enough to see there are several benefits to making the leap from the linear to nonlinear solver. It’s not just a tool for the analyst. It’s for everyone.
If you think you might need some additional simulation capabilities, or you’re interested in a wealth of extra tools and options for interpreting and manipulating simulation results, please consider having a look at the Simulation Add-In.