Approach to an FE simulation of coating damage on bulk metal forming tools

• Determination and FE-modelling of residual stresses in amorphous DLC coatings
• Classification of failure mechanisms of amorphous DLC-coatings
• All-embracing FE-simulation of thin-coated forming tools with special attention on failure effects
• Comparison with thermally sprayed thick coatings

This paper describes the numerical simulation of failure mechanisms of coated forming tools and explains the procedure of a finite element analysis (FEA) of the coating - substrate - system.The development of a static failure model is explained using the examples of thermally sprayed and amorphous carbon coatings. Furthermore, its implementation into the FE model is demonstrated. Sprayed thick coatings are used initially, the developed methods are then transferred to amorphous thin coatings. Necessary thermomechanical material properties, especially in the case of thin coatings, as well as system characteristics such as adhesion strength are insufficiently known. Together with FEA several techniques are employed to determine applicable model parameters using parameter identification. The paper only considers monolayers. In a first approximation both substrate and coating are considered homogeneous and isotropic.