Hello Rahul,
As per my understanding, A trend damping factor of less than 1 decreases(downward trend) the growth rate for each period recursively. Whereas A trend damping factor of greater than 1 increases(upward trend) the growth rate for each period recursively.
Let us say A trend damping factor of 0.5 decreases the growth rate for each period by 50% recursively. If, for example, the number of LED TVs is currently growing by 1000 per period, the growth in the number of cars sold in the next period would be 0.5 * 1000 = 500, and would be 0.5 * 500 = 250 in the period after that, and so on.
It is expected that some period in the future it is bound reach less than Zero value. In this case you will receive error like this - "Trend dampening terminated; negative forecast values"
Refer below SAP Help Link for additional details -
Trend Dampening Options for Exponential Smoothing - Creating a Master Forecast Profile - SAP Library
Hope this will help.
Thank you
Satish Waghmare