- #1

I have read that any given bending moment is equivalent to a force couple applied about that axis. That is to say that the curly moment arrow on a FBD represents a force couple producing a moment. The upshot is that the moment of a couple is the same about any parallel axis, which can be useful for problem solving.

However, one engineering reference page said this

Thus, the internal forces in any cross section of asymmetricmember in pure bending are equivalent to a couple.

I don't see why the internal forces on a non-symmetric member would not be equivalent to a couple? I wondered if you would agree? Thanks!