How to Calculate Shell Edge Load

[msonys]

Hello,
I am working on simple model, a large rectangular plate having different openigs, i want to study the shear case, I tried to apply shell edge load on four sides, but i dont know how to calculate the magnitude as length and height of the plate are different.

shahid

 

[msonys]

units of shell edge load are N/mm. So its force per unit length.