help with Numerical Soln to Differential Eqn

[hrishibhor]

Please help to implement following differential equation numerical solution in mathcad

Numerical solution for single degree of freedom elastic system.
Spring stiffness = k = 2000 lbf/ft
Weight = W = 64 lbf

Force function:
F(t) = 500t+50 if t <=0.1
=-1250t+225 if 0.1 <=t<= 0.14
= 50 if t>=0.14
Acceleration function:
A(t) = ½ F(t) – 1000 *Y

Say time step = dt = 0.02
Initial Condition:
Displacement:
Y0 = 0 that is displacement is zero when t = 0
Y1 = ½ * A0 *dt^2 that is first time step which t = 0.02 this gives displacement but in terms of Acceleration at t =
Acceleration:
A0 = 0 when t = 0

Solution:
Y (t+dt) = 2 * Y (t) – Y(t-dt) + A(t) * dt^2
For t – 0 to 0.4 with dt = 0.02

Return:
Y, A

[MikeArmstrong]

Never cross post.

Why have you posted this twice? Just a pointer - for a collab to help they will have manually type all the data into Mathcad, which takes times. It would be much easier if the question/query is accompanied with a worksheet.

Mike

[RichardJ]

Never cross post.

Now the worksheet has been postyed in the other thread, even though all the comments are in this one. Very irritating!

[hrishibhor]

my bad. This was my first post and so was an mistake Hope that i am not adding to the mess here by attaching the sheet.

Alan Stevens posted a ODE solution but i was hoping to solve it numerically based on the original post. I am attaching my workseet

Again apologise for the inconvenince.

Thanks

[f.kohlhepp]

Weight = W = 64 lbf

Weight is not forcce, it's mass.

Acceleration function:
A(t) = ½ F(t) – 1000 *Y

Acceleration is not force.

There are a number of ways to do this in Mathcad. Odesolve, Rkadapt, etc.

Let's see what you've tried. Post a sheet.

[RichardJ]

f.kohlhepp wrote:

Weight = W = 64 lbf

Weight is not forcce, it's mass.

Weight is indeed force.

[f.kohlhepp]

Richard Jackson wrote:

Weight is indeed force.

Sorry! You're right of course.

Should have said that for this application we don't want force, we want mass. Acceleration is force/mass (most of the time.)

[RichardJ]

Should have said that for this application we don't want force, we want mass. Acceleration is force/mass (most of the time.)

True