High-frequency vibro-acoustics simulation for an agricultural tractor using combined DEA/SEA analysis

Dynamical Energy Analysis (DEA) is a mesh-based high frequency method modeling structure borne sound for complex built-up structures. Simulations are done directly on finite element meshes circumventing costly re-modelling strategies. DEA provides detailed spatial information about the vibrational energy distribution and transmission path within a complex structure in the mid-to high frequency range. We will present here progress in the development of the DEA method towards handling complex FEM-meshes including Rigid Body Elements and sound radiation. The results for simulations are compared to measurements on an agricultural tractor model both for structure borne vibrations and sound pressure levels (SPL) inside the cabin. The tractor consists of a chassis frame including transmission casing and a front frame and a cabin - the latter includes doors and windows. The excitation is applied at rear side of the transmission using a shaker. For simulating the sound pressure level (SPL) at the driver's ear position, a combined DEA/SEA analysis has been developed as a post-processing tool. The DEA results are used as an input for an SEA model consisting of the panels of the cabin and the interior of the cavity formed by the cabin. The simulation results compare favorably with measurement results both for vibration levels measured across the structure and SPLs inside the cabin.