Strength calculations, Rear trailer hitch

I have had some plans on building my own tow hitch and according to SFRO (Svenska fordonsförares riksorganisation) an organisation that controls home build vehicles in close cooperation with the Swedish authorites here i Sweden, I am allowed to build my own tow hitch rated for the maximum totalweight of 1500 kg (3307 lbs). I guess thats close to a class 3 tow hitch that has a 3500 lbs gross trailer weight.
I am not enforced to make a calculation of the tow hitch, but if the inspectors belive it "Looks weak" I am obliged to show a calculations, that shows the tow hitch fullfilles the requirements stated further down in this post.
So has I have the knowledge and the tools why not make a calculation and see what is says??

The statical dimensioning loadcases are:

Axial: Pulling force 0,4mg; Pushing force 0,3mg
Vertical: Downwards 0,3mg; Upwards 0,2mg
Sideways: 0,15mg

With a gross trailer weight of m=1500 kg and g=9,81 m/s2 the above translates to:

Axial: Pulling force 5900N; Pushing force 4400N
Vertical: Downwards 4400N; Upwards 2900N
Sideways: 2200N

The recomended materials for the tow hitch are:

SS1311, SS1312, SS1232; (S235JR)
These materials allows a maximum stress of 170-180 N/mm2 (24.66-26.11 ksi) for the above loadscases.

SS1411, SS1412; (S275JR)
These materials allows a maximum stress of 210-220 N/mm2 (30.46-31.91 ksi) for the above loadscases.

SS2172, SS2173; (S355JR)
These materials allows a maximum stress of 250-260 N/mm2 (36.26-37.71 ksi) for the above loadscases.


Results for combined 5900 N pulling force, Downwards 4400 N and Sideways 2200 N.

This video shows the maximum principal stresses for the combined 5900 N pulling force, Downwards 4400 N and Sideways 2200 N. Maximum stress is around 210 N/mm2. All displacement is enhances x50 to make movements more visible.

This video shows the maximum equivalent stresses (Von Mises) Maximum 210 MPa. All displacement is enhances x50 to make movements more visible.

Same loadcase as above but this video is showing the maximum displacement. Maximum displacement is 1.5 mm (0,059")

Results for combined 4400 N pushing force, Upwards  2900 N and Sideways 2200 N.

This video shows the maximum principal stresses for the combined 4400 N pushing force, Upwards  2900 N and Sideways 2200 N. Maximum stress is around 140 N/mm2. All displacement is enhances x50 to make movements more visible.

This video shows the maximum equivalent stresses (Von Mises)Maximum 140 MPa. All displacement is enhances x50 to make movements more visible.

Same loadcase as above but this video is showing the maximum displacement. Maximum displacement is 1.1 mm (0,043")