Engine noise potential analysis for a trimmed vehicle body: Optimisation using an analytical sea gradient computation technique

For the optimisation of the vibro-acoustic behaviour of vehicle bodies above 400 Hz, statistical energy analysis (SEA) has become a common tool in recent years. Within this paper we would like to introduce a vibro-acoustic optimisation algorithm which is based on an analytical gradient computation of the energy of a subsystem with respect to SEA coupling and internal loss factors. The suggested interface of the method between vibro-acoustic complete vehicle optimisation with respect to SEA parameters and material optimisation in order to design the SEA loss factors, might offer a suitable work flow between OEM or system supplier and trim material supplier. With the help of the analytical gradient formulation, which is represented in Section 2, we show in Section 3 that the energy of subsystems, which constitutes the optimisation function, does not exhibit local extrema in the loss factor parameter space. Therefore, a straightforward optimisation procedure based on the investigation of the vibro-acoustic potentials of loss factors and the calculation of design targets is introduced in Section 4. After validation in Section 5 the method is applied in Section 6 in order to optimise engine noise of a coupé SEA model.