For any new vehicle development, NVH target setting is crucial activity. Structural modification are to be done in early design phase to improve cabin comfort by identifying the sensitive paths and taking appropriate countermeasures for reduction of noise or vibrations transmission to cabin.
A benchmark vehicle is taken to define the target areas for next model development. Numerical computations with suitably modified virtual model are carried out to accelerate the development cycle. Transfer path analysis (TPA) is an established technique for estimation and ranking of individual low-frequency noise or vibration contributions via the different structural transmission paths from point coupled powertrain or wheel-suspensions to the vehicle body [1]. TPA technique can also be used to define the improvement targets for future vehicles.
This paper presents the methodology of carrying out the “Target Setting” using TPA for numerical model development for new model prior actual prototyping which will result into achieving desired NVH level in cabin. The activity has been carried out on Cross-over 2WD platform which has been taken as a benchmark for next generation utility vehicle. Virtual model of subject vehicle is created and correlated with actual vehicle condition. For numerical input, noise transfer function is calculated on subject vehicle using Transfer Path Analysis technique [2] for decisive location inside cabin. Input force is also calculated for contribution analysis over a wide frequency range for different driving conditions. Using the operational data, the problem areas are identified and further improvement target are decided keeping the vehicle class in view. Structure-borne noise is the major source of noise inside the vehicle compartment; hence improvement of bush isolation is identified as major area of improvement.