Abstract This paper makes a research on lateral double moment of generalized force in thin-walled beam,
describes the different influences on the applied condition of bucking direct stress and Saint Venant Principle
by lateral double moment during restraining twist rotation of open thin-walled beam and close thin-walled beam,
and first presents the calculation formula of max，buckling direct stress in thin-walled box beam under effect of
lateral double moment.
2005, Vol. 22 
