Hi,
I'm currently working on a project which involved some oscillation testing of a scale model. The issue I'm having is that there is a phase lag in the output data, i.e. the maximum force does not correspond with a zero crossing of amplitude as it should. Rather, it is either in phase with the force, or anti-phase with the force. I was hoping there was some way to sort this in MathCAD, it isn't a straightforward phase shift as the phase lag differs with each test run. Is there some coding that would allow to me to check for the various times at which amplitude = 0, and then adjust the data in the force column so that Fmax correlates with A = 0? The frequency and thus period are the same, so by sorting the phase shift corresponding to 1 point, the rest of the data should fall in place accordingly. Hopefully, this could be applied regardless of which data file is used so that for all test runs, Fmax correlates with a zero crossing of amplitude, and the results can be readily obtained.
I've created a very basic mathcad sheet to illustrate the problem. The input values for 'Series' and 'File' can be obtained by checking the arrays on page 3 i.e. the 'ID' column in each array refers to the file input, and R1/R4 refers to series 1/4 respectively.
The non-dimensionalised Force vs Amplitude shows a tilt in the graph which highlights the problem - this graph should be an ellipsis around the y axis passing through the origin.
Any help on this is greatly appreciated. I am using MathCAD 15
Thanks