Metodološki pristup razvoju gumeno metalnih opruga

Abstract

The doctoral dissertation defines a new integrated methodology for the development of rubber-metal springs based on the application of modern virtual product development tools. The defined methodology encompasses all analytical, numerical, experimental and optimisation procedures necessary for the virtual rubber-metal springs development process. The main advantages of the new methodology reflect in the decrease in necessary experimental investigations, usage of realistic service loads instead of assumed loads and introduction of design of spring based on transmissibility and damping as the main parameters of the vibration control process. In contrast to the classical approach to rubber metal springs development, where the selection of rubber compound was done solely on previous experience of the designer, the thesis defines the systematic procedure for the selection of rubber compound based on the required spring natural frequency. Furthermore, the dissertation introduces a new procedure for approximate determination of the hysteresis damping value based on the experimental testing by uniaxial compression. The methodology also introduces a new procedure for the determination of heat generation during dynamic loading, as the main factor influencing rubber aging, which completely relies on virtual product development tools. The research into the prediction accuracy of several constitutive models of multiple rubber compounds commonly used in rubber metal springs was also conducted. In order to apply the finite element method in the rubber-metal springs development process, the new procedure for approximate determination of the rubber-metal contact friction coefficient value was developed and the research was conducted on the influence of finite element shape and order selection on the accuracy of rubber-metal springs numerical simulations using the finite element method. By applying the new methodology for the development of rubber-metal springs, the primary suspension spring of the locomotive 441 (444) of the JSC Serbian Railways was developed. The developed spring was manufactured, and laboratory and exploitation investigations were conducted, which led to obtaining the service permit for the railways operated by the JSC Serbian Railways. During the laboratory and exploitation testing the rubber-metal spring performed in accordance with the results obtained by the application of the new development methodology, which verified the new integrated development methodology and proved its practical applicability.