State of the art methodologies for numerical spring design
Springs have a complex geometry. In operation, large elastic deformations occur. Contacts within the spring, e.g. contacts of coils, and contacts to bordering components have to be taken into account. They all lead to great nonlinearities. Further difficulties are caused by spring natural oscillations in dynamic operations such as higher stress levels, friction, noises as well as lateral movements. The experimental analysis of springs is time-consuming. Therefore numerical simulation programs have been used more and more often. These programs are only usable by calculation engineers, specialy trained in the utilized numeric method and in spring technology. Therefore, with the FEM-spring-processor (FEM=Finite-Element-Method) and the MBS-spring-processor (MBS=Multi-Body Systems) two powerful object-oriented programs were developed, both usable without special knowledge of the numeric methods, with an easy-to-use graphical user-interface. The FEM-spring-processor includes modules for different helical springs, torsion springs, Belleville springs and a feature based branch for easy modelling of complex shaped springs made of wire or strip. Nonlinearities can be computed, results are load curves, stresses and natural frequencies. For the analysis of highly dynamic applications, the additional use of MBS is advised. The MBS-spring-processor includes models for helical compression springs. The paper describes the programs and examples of use.