Research on a unified criterion of internal and external wrinkling of strip metal in-plane bending under unequal compressing

The instability wrinkling is the key problem urgently to be solved in the research of strip metal in-plane bending under unequal compressing. A unified mathematic description with more explicit physical meaning of internal and external wrinkling wave on the strip of in-plane bending is established, and it is easy to solve. And a unified criterion of internal and external wrinkling is established, then how to combine the FEM simulation system to make the numerical prediction of wrinkling into reality is also resolved. The experiments carried out show that the unified criterion of the wrinkling is reliable. The effects of the geometrical parameters, the material properties and the friction factor on the deforming result are analyzed by using the unified predict criterion. The results can serve as a significant guide to the design and optimization of the process.