The acoustic characteristics of vehicles are increasingly perceived as an important quality criterion. For an efficient, resource-saving and economic development, it is desirable to assess the dynamic behavior as early as possible in the development process. In particular, the experimental determination of attenuation values and the balance of simulation models is usually possible only with great effort. It can produce a variety of process parameters, such as storage, excitation and the measurement techniques used affect experimental results. Numerically, the dynamic behavior can already be changed by a structure selection of the attenuation model. The aim of this project is to improve the reproduction precision of attenuation values and transfer functions of complex models. In the first phase, the influence of different model approaches to attenuation of different excitation signals and the windowing used in the calculation of response functions in the frequency domain (FRF: frequency response function) to simple one- and two-degree of freedom systems (DOF: degrees of freedom) was investigated. Next, various methods for determining attenuation of experimental modal analysis on the resulting transfer functions are taken a closer look into.
In the second phase, beams are analyzed as a continuum oscillator. In addition to the abovementioned points, the influence of storage in simulation and experiment is considered in more detail. It is further performed a sensitivity analysis with respect to the cross-linking in the simulation and the influence of the calculated transfer functions. The different attenuation models are compared in Abaqus and optionally further implemented.
In phase three, the sample designated as Urdeckel is sent to several research centers in order to obtain a comparison of different methods of measurement and an insight into the distribution of attenuation measurement. Based on this measurement data, the simulation model is calibrated in Abaqus and the influence of the different parameters investigated further which primarily addresses the uncertainties of different excitation and calculation methods as well as the bearings. One approach is to get through the simulation of storage and smaller deviations in comparison with experimental results.
In the last part of the project, the findings out of a practical component (cylinder block, etc.) are applied and further investigated. Throughout the considered project, a large number of possible influencing factors are analyzed. The investigations on simple models and samples, the effects of the individual effects can efficiently evaluate and identify the reliable relevant factors.
