I performed a shaking table test.

I put the object on the table and fastened it by belt to the table. I moved the table up and down, and I measured tension applied to the belt and vertical acceleration of the table.

I got 2 time series data and I attached a part of them to this post.

Sampling frequency is 10[Hz].

X-axis represents time for 40 sec, and Y-axis represents tension [kN] and acceleration [m/sec^2] respectively.

It looks that there is an antiphase relation.

Now, I want to know how large tension response occurs in relation to the magnitude of the acceleration.

For example, in the red box, about 0.4 [kN] amplitude of tension is applied to the belt under condition of 1.5 [m/sec^2] amplitude acceleration.

This graph is just a sample, and I have much longer duration data (about 1week), so I would like to effectively analyze the relation between tension amplitude and acceleration amplitude.

But, I could not find a good way to extract amplitudes from time series data.

If you have any good idea, I would appreciate it if you would teach me.

Thank you.