Squeak & Rattle Simulation - A Success Enabler in the Development of the New Saab 9-5 Cockpit without Prototype Hardware

To achieve “right first time” design for SAAB projects, thus avoiding unnecessary development loops, a squeak & rattle simulation tool was required. This paper presents a new squeak & rattle simulation approach which covers the complete development process of interior parts. The process starts with a rough model, which is mainly based on styling data and ends with a model of a very high detail level close to serial tooling status. The detailed CAD model is then represented by a simulation model of similarly increasing quality. By using different types of analyses in the frequency and time domains (modal analysis, frequency response and transient analysis), the output of these simulations can be matched to the available FE model quality. During initial development the global behavior of the structure is of interest. Finally the relative displacement between two detailed trim parts is used to evaluate the risk for squeak & rattle. In order to identify the capability of the squeak & rattle simulation different correlation work between test and simulation has been performed. Examples of modal correlation on a global and a local level of the interior assemblies are shown. Also a procedure which enables the correlation between the tested and simulated relative displacement due to a random load is presented. This new squeak & rattle simulation has been used during the development of the new SAAB 9-5. Different examples of how the simulation results supported and guided the cockpit design clearly justify the benefits of this approach.