A Proposed Methodology for Calculating the Rigid Body Natural Frequencies of EPDM Rubber Fixed Supports with the Finite Element Method (FEM)

Abstract

This paper proposed a methodology for calculating the rigid body natural mode shape and frequencies of a piping system that are formed by a compressor and rubber supports with the aim to improve its reliability and durability. The rubber supports are manufactured by Ethylene Propylene Diene Monomer (EPDM) hyperelastic material. The methodology combines the Finite Element Method (FEM), experimental modal analysis (EMA) and ANSYS Workbench parameter evaluation software. First and using SpaceClaim Software, the geometry of the EPDM support was generated and imported in the ANSYS Workbench Finite Element Analysis Software. Then, a 3D parameterized finite element model was created in ANSYS Workbench considering tetrahedral elements with linear formulation. An experimental modal analysis was performed on said rubber supports, and using Brüel & Kjaer BK Connect Modal Analysis and BK Connect Geometry Software, the rigid body natural mode shape and frequencies were obtained. Subsequently, these natural mode shapes and frequencies obtained experimentally were compared with those obtained from the ANSYS Workbench Finite Element simulation varying Young’s Modulus of rubber supports. An agreement between the natural mode shapes and frequencies obtained from the experimental analysis and the FEM demonstrates that the proposed methodology could be valid for improve the design process of these type of products.