I'd like to calculate the damping ratio of a structure based on acceleration data.
To do so I usually take the logarithmic decrement of a nice sinusoidal wave. However, in certain cases I obtain waves that do not allow me to do so easily thus I would like to create a trend line that follows the peaks as shown in the PDF attached. With this curve I could estimate the overall damping of the structure.
The image below shows graphically what I would like to do.
Thank you in advance