When the load is not large, the beam is basically in its maximum stiffness plane bending, but when the load is large to a certain value, the beam will produce a large lateral bending and torsion deformation, and finally very quickly lose the ability to continue to carry.At this time, the overall instability of the beam must be lateral bending and torsional buckling.
There are three solutions.
1, increase the beam’s lateral support points or reduce the spacing of lateral support points
2, adjust the beam cross-section, increase the beam lateral moment of inertia Iy or simply increase the width of the compressed flange (such as crane beam on the flange).
3, beam end bearing on the cross-section constraints, bearing such as can provide rotation constraints, the overall stability of the beam will greatly improve the performance.