Stochastic radiated sound power of structures with uncertain parameters

Due to the limited precision in any production process, manufactured geometries differ from the designed shape and therefore the dynamical and acoustical behaviour varies with the form of the structure. This means, that any numerical simulation of the structural dynamic and emitted sound is fraught with uncertainties. For a more precise and reliable simulation of the natural frequencies and the emitted sound, it is necessary to have accurate knowledge of the influence of the uncertainties of geometrical parameters. This especially applies, if the (pre-)product has to be optimised for its dynamical respectively acoustical properties. The stochastic vibro-acoustic analysis of sheet steel subjected to material and especially geometrical uncertainties is studied in this paper. To this end, the random eigenfrequencies and the equivalent radiated sound power are calculated. Therefore, the impact of the uncertainties is investigated by simulating a planar steel plate. The uncertain material and geometrical parameters with predefined probability density functions are assigned as model inputs. Using the Monte-Carlo-Simulation the systems' random responses are obtained. To reduce the number of experimental validations in a development process, the influence of each single uncertain parameter on the natural frequencies and equivalent radiated sound power is investigated in this study.