Warpage deformation behavior of metal laminates

Abstract

The layered characteristics of the material in the thickness direction of the metal laminate make it more prone to uneven plastic extension during the thinning, rolling, flattening, and straightening process, resulting in plate-shaped warpage defects and cause the plate-shaped warpage of the metal laminate. The behavior is significantly different from that of a homogeneous metal plate. In this paper, the classical elastic mechanics method was used to establish an analytical computational mechanical model for the warpage of the metal laminate, and the quantitative relationship between the uneven extension in the thickness direction and the warpage of the plate shape was obtained; the online and offline states of the metal laminate were established, respectively. The finite element numerical simulation model of warpage deformation validated the analytical computational mechanics model; based on this, it revealed the mechanical roots of the shape warping defects of metal laminates and the effect of various factors on the shape warpage defects of metal laminates. The influence law of evolution and the difference in warpage deformation between double-layer and three-layer structure laminates and homogeneous plates, as well as the difference in warpage deformation between copper/carbon steel laminates and stainless steel/carbon steel laminates, were compared. Studies have shown that the warpage height of the metal laminate is proportional to the elongation difference and thickness ratio, and it is inversely proportional to the thickness. The greater the difference between the shear modulus of the base layer and the cladding layer is, the larger the effect of the thickness ratio on the warpage deformation of the metal laminate will be. Based on the numerical model, simulation studies were conducted on the deformation behavior and regularity of the plate shape warping of the laminated plate under the ideal uniform distribution of the initial temperature and the stress relief annealing process, and it was compared with that of the homogeneous plate. Finally, a sample of the warped laminate was taken at an industrial production site, and the initial extension difference was reversed by measuring its bending deformation. The result verifies the accuracy of the analytical computational mechanical model.

Keywords

• metal laminate
• warpage
• longitudinal extension
• analytical method
• finite element