I doubt that there is a collapsible walking stick that would survive a full force blow at half its length. At least I have not found one. And I have been looking for years. To be at all effective it has to have some weight as well as strength.

I have not found a hollow rod of a size and weight that would meet walking stick criteria that would take such a punishment.

That said, there are several things you can do with a typical walking stick that would help if you were in a bad situation.

My favorite is if someone grabs you by the lapels, swing the stick over their arms, hold both ends and push it up their arms into the throat. With practice you can do that very fast. Probably break the stick, but ...

A two handed thrust with the point into some soft tissue is also effective.

However I would not recommend relying on such tactics. But if you have the stick in your hands, at least it has some use.

Let me know if you find one that is strong enough.

Nomad... been beating things with sticks for a long time.