Holzer's method uses excel's goalseek function to iterate or more exactly, to step or march to a solution. There are as many modes as there are torsional springs so you will have to goal seek different ranges until you find them all. The plot is meaningful as it will show you nodal crossings and help guide your seek ranges until you converge on the next mode. As always, just send me a comment and I'll try to help you out.
|Watch your UNITS!|
|Formulas are pretty straight forward...|
|Use goalseek to converge on a mode|
|Some common unit conversions|
|Simple stuff, but handy.|
Have a great day!