Variable Spring/damper parameters

[9msl1]

Hello

Is it possible to define a spring constant or damping constant that can follow a load curve for non-linear analysis such as mechancial event simulation?

Thanks

[AstroJohnPE]

Spring, yes. A "General contact element" has 2 spring constants in tension and 2 in compression. You can also use a truss element with the material model set to "Curve". This type of truss element has input for a stress strain curve which is equivalent to a force displacement curve = spring constant. So you can define as many intervals as desired.

Damping, no.

[david.cross]

john

how can this be applied to cad geometery, IE a model of a wire rope isolator

thanks

david

[9msl1]

Hello 

Thanks for your advice!

Btw. I have another issue that you may be able to help me with.  My computer crashed halfway through a 60h simulation and now I only have half the results.

Is there anyway to get multiphysics to "pick up where it left off."  I'd hate to waste 3 days reduing the analysis...

Thanks very much.  It is very appreciated

[AstroJohnPE]

In case you did not see the response in one of the other threads, the answer is yes: you can restart a crashed MES analysis, and it will restart at the last completed time step.

For your other question about creating a nonlinear spring from a CAD part, if you meant that you want to assign a CAD part to truss or general contact type of elements, that cannot be done. I cannot think of any other material model that would let you use a CAD model (brick elements) and make it behave like a nonlinear spring.

You will need to figure a way to replace the CAD part with a single line that you draw in Sim Mechanical. (Or it can be multiple lines, whatever it takes to simulate the CAD part.)