Derivative of an equation for prediction of a filament strain under low yarn strain ∑▒〖y≤10%)〗

Derivative of an equation for prediction of a filament strain under low yarn strain (∑▒〖y≤10%)〗

This derivative was developed by Platte’s Model. The model shows the extension of filament in yarn under low tension.
 Let,    H = height of yarn having one turn of twist
         ∂h = yarn extension
          l = Length of the filament
         ∂l = Filament extension
         Θ = Helix or twist angle

Equation to predict filament strain for any given yarn strain ∑▒〖y≤10%)〗 at helix angle θ