Analysis and modeling of plastic wrinkling in deep drawing

Yalçın, Serhat
Deep drawing operations are crucial for metal forming operations and manufacturing. Obtaining a defect free final product with the desired mechanical properties is very important for fulfilling the customer expectations and market competitions. Wrinkling is one of the fatal and most frequent defects that must be prevented. This study focuses on understanding the phenomenon of wrinkling and probable precautions that can be applied. In this study, dynamic – explicit commercial finite element code is used to simulate deep drawing process. The numerical experiments are compared with NUMISHEET benchmarks in order to verify the reliability of the finite element code and analysis parameters. In order to understand plastic wrinkling, the effect of blank holder force is investigated. Axisymmetrical numerical models of a cup are investigated with different blank holder forces. Wrinkling instability is illustrated in energy diagrams of the process. Effect of anisotropy on wrinkling is also discussed by comparing isotropic and anisotropic numerical experiments with the material as steel. Different drawbead models, both equivalent and physical, are implied to the problem and results are discussed. Besides numerical analysis, experimental verification is also conducted as conventional deep drawing operation by a hydraulic press. This yields to the ability to understand the effect of blank thickness on wrinkling formation through numerical and experimental analyses. The wave formations of different sized blanks with four different thicknesses are illustrated.
Citation Formats
S. Yalçın, “Analysis and modeling of plastic wrinkling in deep drawing,” M.S. - Master of Science, Middle East Technical University, 2010.