A new test method for sheet metal deformation subject to tension under cyclic bending and compression (TCBC)

A new test method for sheet metal deformation, Tension under Cyclic Bending and Compression (TCBC), is developed in this study. The TCBC method is capable of testing material deformation under tension, bending, and compression with cyclic loading. The effect of each deformation mode can be independently controlled by adjusting corresponding parameters. Using the TCBC test rig developed, aluminium alloy AA5251-H22 is tested under four different testing conditions: simple tension, tension under cyclic compression, tension under cyclic bending, and tension under cyclic bending and compression. The maximum elongation of the tested specimen at fracture and the tensile force required for material plastic deformation are evaluated. The results show that the maximum elongation increases significantly under the TCBC condition due to localised plastic deformation under compression that delays the fracture. Finite element modelling of the TCBC test is developed to obtain stress distributions to explain the enhanced formability. The new TCBC method may be used for testing material formability that resembles double-side incremental forming.