This conference paper was submitted for presentation at the NAFEMS World Congress 2025, held in Salzburg, Austria from May 19–22, 2025.

Abstract

Despite their extensive use in industrial applications through the past decades, modelling rubber-like materials can be very challenging when it comes to solving the system dynamics. Beside their complex geometries, the nonlinear material behavior makes rubber parts behavior unpredictable and increases the uncertainty level of dynamic systems. Due to the material structure, the mechanical response of these partes highly depends on excitation amplitude and the frequency. Besides, due to high elongation capacity the material undergoes large deformations which in turn leads to complex local bucklings and also contact non-linearities. In this study an integrated and hybrid finite elements-multibody dynamics approach has been adopted to optimize the design of a washing machine rubber gasket based on dynamic performance targets. This gasket application is probably one of the most challenging elastomer applications in industry due to its relatively large dimensions and harsh loading conditions in which the material undergoes significant and complicated deformations under varying excitation frequencies up to 25 Hz. Firstly, the elastomer material was characterized in detail to derive a comprehensive visco-hyperelastic constitutive model. Using this material model a non-linear finite element modelling approach has been developed to capture both viscoelastic behavior and also contact non-linearities under dynamic loading scenarios. Secondly, a detailed multibody dynamic model of the system was developed to test the dynamic performance of the system when using alternative gasket designs. Secondly, several random curves were generated to create alternative forms for axisymmetric design of the gasket. Using these forms, ideal axisymmetric designs were created. After evaluation of these designs according to calculated dynamic stiffness values an initial gasket form was created. Next, the dimensions of different segments of the initial form were parameterized. By applying size optimization iterations, an optimum form was created. Using the generated optimum form, a detailed design for the gasket has been developed and the dynamic stiffness behavior of the final design was calculated in three translational and three rotational axes. Using the calculated dynamics stiffness values a nonlinear bushing component was developed for the new gasket. The performance of the new and old designs of the gasket was evaluated in detail using the multibody dynamic model and the deformation levels on the gasket under operating conditions of the dynamic system were calculated. These deformation levels were applied as boundary conditions in finite element simulations and the durability of the design was evaluated in detail and approved numerically. The finalized design was prototyped. Detailed physical tests were carried on and the durability of the gasket design were approved experimentally as well. Additionally, the stability performance tests on the washing machines with the new optimized gasket reveal a remarkable increase of %30 in stability limits unveiling the success of the optimization study. The integrated approach proposed in this study can be adopted by researchers to develop optimum and more reliable gasket designs for dynamic applications.