Wilson-Theta Time History Analysis

[OLUBUKOLAADEBOY]

Good Afternoon Community,

Attached is a copy of Mathcad 15 file that I'm working on. I'm trying to convert a Matlab code into Mathcad file, I have done some work on the worksheet, but I ran into problem in converting Matlab programming into Mathcad programming. The Matlab code is at end of the worksheet. Would anybody please help me with the worksheet, my goal is to plot the time history of displacement, velocity and acceleration. Thank you in advance.

Boyer

[terryhendicott]

This is my final worksheet that incorporates the correction to zz and includes units.  This is should be marked as the solution.

[OLUBUKOLAADEBOY]

Good Morning Terry,

Thanks for your help.

Boyer

[terryhendicott]

The formula for kh in the Mathcad sample is unit inconsistent

k is mm^4

next term 3c/theta.dt is kg^0.5*m^2/s

third term is 6*ma/(theta*dt)^2 is kg/s^2

units for kh cannot be decided by Mathcad if units are applied to values.

The equation for kh as supplied in Matlab image is probably wrong!

You must use unit consistent values  without using units for solution as presented in Mathcad.

[OLUBUKOLAADEBOY]

Good Afternoon Mathcad Community,

Attached is a modified copy of FM Wilson-Theta  Mathcad file with units. The displacement ploted correctly but the velocity and the acceleration did not plot correctly. Would anybody be kind to take a look at the file an tell me what I'm missing in the code.

Best Regards,

Boyer

[Werner_E]

Maybe you confused yourself with variable names 😉

Plot "vel" or "vel_2" over time, not "v" !

BTW, the way you did it you call your functions three times which is quite inefficient.

Its better to do it as follows:

Concerning the plots I would suggest that you divide the variables in the plot by the appropriate unit. That way you are not limited to Mathcads standard units but may show miles per hour over milliseconds or whatever you like:

Furthermore, as you use labels for the axis, you may consider to hide the arguments for a cleaner display.

[OLUBUKOLAADEBOY]

Thanks Werner.

Best Regards,

Boyer