The Shear Center in Creep of Beams of Thin-walled Open Cross Section

Abstract

It is shown that in the case of creep bending of beams of thin-walled open cross section, in general, the neutral axes do not intersect at one point and that the concept of the shear center fails. The shear center is replaced by a family of straight lines such that when the plane of bending passes through such a straight line the cross section will suffer no torsion. These torsionfree axes do not intersect at one point except in special cases. The family of the neutral axes and the family of the torsionfree axes correspond to each other and they depend on the magni tudes of the bending moment and shearing force. When the creep law has the form σ = A ε n the two families are independent of the magnitudes of the bending moment and shearing force. The implication of this result is that for torsionfree bending of a beam to be possible it is necessary to have the above creep law. Exceptions to this result are discussed. Expressions useful for the calculation of the two families of straight lines are given.KeywordsNeutral AxisLongitudinal StressMoment VectorArbitrary Cross SectionShear CenterThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.