Noise and vibration characteristics of certain systems can be random by nature. Therefore, in order to accurately tackle noise and vibration problems, engineers must address them from a random, statistical point of view. For example, the high acoustical excitations induced by a powerful jet or rocket flow, are random by nature and induce random vibrations into the aircraft fuselage, spacecraft launcher fairing panels or satellites.
LMS Virtual.Lab Random Vibro-Acoustics is specially developed to assist in solving these random problems. This complete solution addresses both the structural responses and the acoustic response. For the structural response, it is possible to assess the vibration amplitudes due to a random acoustic excitation. For the acoustic responses, the solution supports the transmitted and scattered sound due to random structural and/or acoustical excitations. LMS Virtual.Lab Random Vibro-Acoustics is a flexible and full featured solution incorporating structural and acoustical load calculations, mechanical force spectra (PSDs) and acoustic wave excitation, including diffuse fields and partially coherent loadings.
In terms of structural responses, the solution pack offers not only the possibility to calculate vibration amplitudes (power spectra), but also supports stress recovery by providing stress spectral densities for the structural elements based on the stress modal vectors obtained by standard FE solvers. As such, engineers can assess critical points of a structure in terms of vibrations and in terms of stress levels.
The acoustic mesh can be created using Virtual.Lab, saving weeks of modeling time, or by general CAE pre-processors. The solver then takes into account the deterministic and random characteristics of the behavior, with the option to go for a fully coupled model of the two-way, fluid-structure interaction or one way coupling.
Using dedicated post-processing tools, the engineer can analyze the results in a straightforward way to determine if focus must be placed on sound transmission or structural response, and then use either the Fast Modification Prediction to assess the influence of structural changes on the vibro-acoustic responses, or the Mesh-Based Design Tool to apply structural changes directly on the FE model.
