-->//(Springs) Example 10.20
 
-->//Pre-load on the compression spring Pmin (N)
 
-->Pmin = 375
 Pmin  =
 
    375.  
 
-->//Permissible torsional shear stress in the spring tau (N/mm2)
 
-->tau = 750
 tau  =
 
    750.  
 
-->//Permissible outer diameter of the spring D (mm)
 
-->D = 42
 D  =
 
    42.  
 

The design is safe

Wire diameter(d) = 5.000000 mm

Mean coil diameter(Dmean) = 37.000000 mm