Abstract:
This thesis explores a methodology to translate the hardness numbers of polymers and elastomers into useful parameters for Finite Element Analysis (FEA), as these hardness numbers, commonly provided by suppliers (such as Shore and IRHD), cannot be directly used in FEA software. The study focused on simulating hardness tests for one Shore method and two IRHD methods. The methodology involved creating 2D axisymmetric and 3D FE models of the test equipment and the material being tested. Due to symmetry, the 3D models were simplified to 2D models to significantly reduce computation time and simplify contact problems between the indenter and the test material. The simulations used LS-DYNA, with material models like *MAT_MOONEY-RIVLIN_RUBBER for rubber-like behavior and *MAT_PLASTIC_KINEMATIC for plastics. To find the material parameters corresponding to specific hardness values, an optimization process was performed using LS-OPT. The methodology successfully established a relationship between hardness and material parameters, although it was found that multiple combinations of parameter values could correspond to the same hardness number, indicating that the solutions were not unique. It was concluded that supplementing hardness tests with other experimental data, such as a tensile test curve, could lead to more unambiguous results. The verification of the method using the *MAT_PLASTIC_KINEMATIC model on known plastic material data showed good agreement, proving the method's potential to derive finite element parameters from hardness numbers.
