• Finite Element Modeling Of Photoplastic Process In The Cold Drawing Of Polycarbonate Bars

      Choi, Dong Ju; Lee, Jonah H. (2001)
      The numerical simulation of the mechanical behavior and the photoplasticity method of polycarbonate have been studied by simulating an existing photoplastic experiment of a cold drawing process. This study will allow understanding the mechanical and optical behavior of polymers and also assessing of the adequacy of existing numerical models and the photoplastic experimental method such that both can be validated and improved in the future. We proposed several optical-mechanical relationships for the photoplasticiy method and also adopted two existing viscoplastic models for polymers. Among the studied optical-mechanical relationships, the Non-Gaussian optical-mechanical relationship for photoplasticity of large deformation of polycarbonate is found to agree well with existing photoplastic calibration tests. Two types of viscoplastic numerical models adopted in this study are the physically based constitutive model and the phenomenological constitutive model with J2 flow theory. The model with the physically based constitutive model and a non-Gaussian optical-mechanical relationship for the photoplastic method could simulate the cold drawing experiment better than the phenomenological viscoplastic model. This study included a parametric study of the physically based constitutive model with the imperfection geometry and several material property variances to understand the mechanical and optical behavior of polycarbonate.