Sensitivities in the Production and Design of EPDM Rubber Springs
Abstract Modeling and robustness are two major concerns in the design and fabrication of rubber springs. This work is part of an extended program to investigate the relationships between rubber formulation, spring design, production variables, and spring performance throughout their useful life. The robustness of an EPDM compound to variations in composition or process parameters has been evaluated. The effect of crosslinker content, source of carbon black and mixing, was assessed in terms of standard mechanical properties. The elastic moduli were measured on lab size specimens and used to successfully model the behavior of a large toroidal rubber spring. Modeling included tailoring the cross-sectional shape and chamfering the corners to reduce strain levels, thus enabling spring compression up to 25% of its height with moderate strain. The spring behavior is unaffected by the scatter in friction at assembly stage or during service. The cross-sectional shape is shown to be a major factor in the spring behavior.