Integration in the time domain - forced SDOF system

[TulaRen]

I would like to do a simple simulation of a single degree of freedom system with a known excitation force in the time domain, i.e.,  integration in the time domain. 

It is a very common problem, and someone must have done it before. So instead of re-writing code from scratch, just wonder if someone would like to share the LabVIEW code if he has it?

Thanks.

Ian

[JustNI]

Hi TulaRen,

There is a function in LabVIEW called “Numeric Integration”, an explanation of which can be found here:

https://www.ni.com/docs/en-US/bundle/labview-api-ref/page/vi-lib/analysis/8numeric-llb/numeric-integ...

Is this what you are referring to as integration in the time domain?

[TulaRen]

JustNI

No really.

The method I am looking for is for solving a second order differential equation (the classic "forced dynamic response of a single degree of freedom system" issue)

ma(t)+cv(t)+kx(t)=f(t)

where

a is the acceleration

v is the velocity

x is the displacement

f(t) is a known excitation in the time domain.

m,k,c are corresponding mass, stiffness and viscous damping of the system, respectively.

Thanks.

Ian

[JustNI]

Hi Ian,

Sorry, I’m not super familiar with this subject, it’s been some time since I’ve had to work with differential equations. Have you already taken a look at the “Shooting Method.vi” example in LabVIEW or the ODE Solver VI (https://www.ni.com/docs/en-US/bundle/labview-api-ref/page/vi-lib/gmath/ode-llb/ode-solver-vi.html)? While these may not be exact solutions to your problem, they might give you an idea of how to go about solving it.

As well, do you have access to the Control Design and Simulation Toolkit? If this is something you need to do on a consistent basis or may need to expand on, it may prove to be helpful. 

Hopefully some of this information is helpful