How to define the nonlinear stiffness of the hard stop component in a Simscape model?

I want to use a nonlinear hardstop model to represent a soft material, as the following simplified model shows, the model would have a hard stop and a torsional spring damper, for the hardstop component I want to make the contact stiffness to be a nonlinear value, either from a lookup table or an equation related to the rotational angle.

Thank you.

Answer 1

[Steve Miller]

There are many ways to create a nonlinear hard stop.

1. Custom code: The most flexible way would be to take the source code for the rotational hardstop (click on the Description tab), save it to a new file, and put your own equation or lookup table in there.
2. Custom schematic: You can create a nonlinear spring by assembling an ideal Force Source, and then calculate the value of the force using the Physical Signals library (to avoid an algebraic loop). There are lookup table blocks there, or you can implement equations.
3. Nonlinear Spring Block: The Nonlinear Translational Spring in Simscape Driveline lets you define the spring as a lookup table, and it can be asymmetric. This lets you define a nonlinear hardstop.

--Steve