What was the purpose of putting all the great powers that had helped to defeat the axis power on the security council

TO assert the power of the nations as the upholders of virtue and might in the world.

Explanation:

There was a common assertion that the sides that won the war were at the moral high ground and thus would be in a position to reap benefits from it and were responsible for the future safeguard of the world in the position of another conflict.

Thus the security council in the UN was formed by the primary sides on the conflict who won the war and then they were responsible for keeping the peace of the world.

im not sure on this one