Mass spring damper with k being a function of x

[MChristensen1]

All,

I am trying to set up an odesolve function with a mass spring damper where my spring constant is a piecewise function associated with position. Sort of like a mass is being driven by a force while being acted upon by a damper until it suddenly hits a spring. Any Ideas?

[ValeryOchkov]

Odesolve with if - one example

[Werner_E]

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@MChristensen1 wrote:

All,

I am trying to set up an odesolve function with a mass spring damper where my spring constant is a piecewise function associated with position. Sort of like a mass is being driven by a force while being acted upon by a damper until it suddenly hits a spring. Any Ideas?

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OK, and where did you experience problems?

It may help if you would attach your worksheet so we can see what you are trying to do.

[tietjee]

You have picked an interesting problem.  I have seem a similar problem  a pendulum and changing the length based on angle.  In this case it was a child's swing.  Pumping (which changes the length) increases the height.  Adding a forcing function is a good start.  The solution was done using Perturbation Methods.  It treats the non linearity of the equation.  This was over 40 years ago.

Good luck

David 

[Fred_Kohlhepp · Accepted solution]

Express can't use solve blocks.

Does this give you a place to start?  (Sorry for the mess--this was a work in progress.)