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This paper presents a study of experimental transfer path contribution with the estimation technique of the projected operational force under CVT clutch lockup operational condition. Since transfer path analysis is conducted with respect to the evaluation location, the forces applied onto the substructures are, therefore, also required to estimate the coherent operational forces. In order to estimate the forces, the coherent inertance matrix, which is the projection of the inertance matrix onto the subspace with respect to the evaluation location, is estimated without measuring it directly. The acceleration responses at the connections of the passive substructure are measured by the excitation at the evaluation location with reciprocity. The proposed technique decomposes the acceleration responses into the output and input element vectors on the subspace. With those vectors, the coherent full inertance matrix considering cross coupling effects is constructed.

This paper presents a new technique to estimate the coherent operational forces, with respect to the evaluation location, at the connections of separated passive substructures with reciprocity. Since transfer path analysis is conducted with respect to the evaluation location, the forces applied onto the substructures are, therefore, also required to estimate the coherent operational forces. In order to estimate the forces, the coherent impedance matrix, which is the projection of the impedance matrix onto the subspace with respect to the evaluation location, is estimated without measuring it directly. The acceleration responses at the connections of the passive substructure are measured by the excitation at the evaluation location with reciprocity. The technique decomposes the acceleration responses into the output and input element vectors on the subspace. With those vectors, the coherent impedance matrix is constructed.

Road Noise is generated by the change of random displacement input inside the tire contact patch. Since the existing 3 or 6 directional electromagnetic shakers have a flat surface at the tire contact patch, these shakers cannot excite the vehicle in a manner representative of actual on-road road noise input. Therefore, this paper proposes a new experimental method to measure the road noise vehicle transfer function. This method is based on the reciprocity between the tire contact patch and the driver's ear location. The reaction force sensor of the tire contact patch is newly developed for the reciprocal loud speaker excitation at the passenger ear location. In addition, with this equipment, it is possible to extract the dominant structural mode shapes creating high sound pressure in the automotive interior acoustic field. This method is referred to as experimental structure mode participation to the noise of the acoustic field in the vibro-acoustic coupling analysis.

A finite element (FE) model of vibro-acoustic coupling analysis, such as a vehicle noise and vibration, is utilized for the improvement of the performance in the vehicle development phase. However, the accuracy of the analysis is not enough for substituting a prototype phase with a digital phase in the product development phases. Therefore, conducting the experiments with the prototype vehicle or the existed production vehicle is still very important for the performance evaluation and the model validation. The vehicle noise transfer function of the road noise performance cannot be evaluated with the existed excitation equipment, such as the 3 or 6 directional electromagnetic shaker. Therefore, this paper proposes new experimental method to measure the road noise vehicle transfer function. This method is based on the reciprocity between the tire contact patch and the driver's ear location.

This paper presents new technique to estimate the projected operational forces, which is the operational forces with respect to the evaluation location, at the connections of the separated passive substructures with reciprocity. Since the transfer path analysis (TPA) is conducted with respect to the evaluation location, the forces for the substructures are, therefore, also required only to estimate the projected operational forces. In order to estimate the forces, the projected inertance matrix, which is the projection of the inertance matrix onto the subspace with respect to the evaluation location, is estimated without measuring it directly. The acceleration responses at the connections of the passive substructure are measured by the excitation at the evaluation location with the reciprocity. The technique decomposes the acceleration responses into the output and input element vectors on the subspace. With those vectors, the projected inertance matrix is constructed.

For a numerical model of vibro-acoustic coupling analysis, such as a vehicle noise and vibration, both structural and acoustical dynamic characteristics are necessary to replicate the physical phenomenon. The accuracy of the analysis is not enough for substituting a prototype phase with a digital phase in the product development phases. One of the reasons is the difficulty of addressing the interior acoustical characteristics due to the complexity of the acoustical transfer paths, which are a duct and a small hole of trim parts in a vehicle. Those complex features affect on the nodal locations and the body coupling surface of acoustic mode shapes. In order to improve the accuracy of the analysis, the physical mechanisms of those features need to be extracted from experimental testing.

The accuracy of the vibro-acoustic coupled system model for the low frequency range depends on how accurately modal characteristics are represented at the input, output, and the structure-acoustic coupling surface. This study focus on extracting the detailed acoustic mode shapes on the coupling surface for the improvement of the model accuracy. In order to extract the acoustic mode shapes on the coupling surface from an experimental test, the applied method is initially evaluated by FE model results. As the next step, the same procedure in the previous step is applied to the test data of an actual vehicle for the purpose of extracting the detailed acoustic mode shapes at the coupling surface of the body structure and cabin interior acoustic field.