The Plastic Bending of Beams Considering Die Friction Effects

This paper describes a theoretical and experimental analysis of the behavior of simple beams bent by a central load while freely supported at each end. Both plane strain and plane stress conditions and the effect of friction at the beam supports are considered. Materials tested are SAE 4130 steel and titanium 6Al-4V alloy. It is concluded that in beams, whose length between supports is at least 25 times their thickness, the load required to effect deflection is increased by the amount required to overcome friction, but does not affect the circumferential strain at midspan. Theoretical methods of analysis correlate well with experimental results and allow the computation of stresses and strains from the beam geometry and true tensile curves of the materials.