Transmission loss of aluminum extruded panel

A design of aluminum extruded panel for achieving reduction of vehicle interior noise level of high speed trains (HSTs) has been proposed. The reduction in vehicle noise is achieved by an increase in the structural transmission loss at the specific frequency band of interest. Since the vehicle noise level for an octave band with the center frequency of 500Hz plays an important role in quiet vehicle design, the local resonance frequencies of an aluminum extruded panel have been increased by altering the panel core section. The cross section of the vehicle floor has been redesigned without altering the total body mass of the structure. The proposed method is found to lead to an extra transmission loss at the specific frequency band which in this case is the frequency band with the center frequency of 500 Hz. A modification of the cross section of extruded panels provides better sound insulation performance for the HSTs. The next generation HST is currently on a test track undergoing noise evaluation at the top operating speed of 400 km/hr.