ELASTIC STRESSES FOR PIPE ELBOWS SUBJECTED TO IN-PLANE OPEN-BENDING MOMENTS
In order to evaluate the engineering safety of pipe elbows,a mechanical model has set up to formulate the meridian stress of pipe elbows subjected to open-bending moments.The construction of the meridian-stress formula due to open-bending moments has the similar appearance with that due to close-bending moments.Except for the relation of tension stress and compress stress transforming each other on the same place,there are different values in meridian stress.The open-bending meridian stress is always larger than close-bending meridian stress for different bending moment coefficients and different angles on the cross section.But the formula-shape of open-bending circumferential stress looks identical with that of the close-bending one.Their stresses have equivalence and reverse relation.Under the action of an in-plane bending moment,elastic stress of pipe elbows just is a special case of the elastic stress of reducing elbows.The elastic stress of reducing elbows may be attained by replacing the cross-section radius of pipe elbows with that of the reducing elbows.