Theoretical analysis of three-point bending with flattening of tube

摘要

Three-point bending behavior of a tube is calculated by the energy method. This calculation includes not only flattening by the bending moment but also flattening by pressing of the punch at a loading point. The calculated results agree with the results obtained by the three-point bending test. In particular, the maximum bending load can be estimated accurately by this calculation method. The optimum size of the tube under the same cross section area was determined by this calculation method. The maximum bending load increases with increasing diameter, but it is smaller in the case of extremely large diameter because of flattening. This optimum size of the tube is not influenced by the cross section area but by the span of bending.