STATISTICAL-MECHANICS MATERIAL MODEL FOR THE CONSTITUTIVE MODELING OFELASTOMERIC COMPOUNDS

Material models for the finite element analysis (FEA) of polymeric and elastomeric compounds are only available in limited form in most comm ercial finite element (FE) packages. The most common are the phenomeno logical Mooney-Rivlin and the Ogden models,for which the constants bea r no relationship to the physical or chemical characteristics of the r ubber and their derivation is difficult. Both models are limited in th eir accuracy for filled rubbers used in combined states of tensile and compressive deformation, and since these are common operational condi tions for engineering components such as drive couplings, engine mount s and torsional vibration dampers, their use in engineering analyses i s restricted. In this paper a statistical mechanics material modelling approach for synthetic, filled elastomeric compounds in FEA is presen ted. Using styrene-butadiene rubber (SBR) as an example, the theory an d its application in the commercially available ABAQUS finite element analysis program is explained. FE models of tensile and compressive sp ecimens in two and three dimensions are used to demonstrate the use of the model, and results are presented, discussed and compared with mea sured data. Good correlation in both tension and compression is demons trated. A practical application of the model to the SBR blocks in a Ho lset torsional drive coupling is presented; this analysis involves com plex issues of mesh design and contact modelling. The results show goo d agreement with measured performance, and clearly demonstrate how thi s type of material modelling approach can be effectively used in the c omputer aided engineering and design of engineering rubber components.