Revealing the sound insulation capacities of TPMS sandwich panels

Triply periodic minimal surface (TPMS) sandwich panels have superior characteristics, including lightweight and extraordinary mechanical properties, so that they are widely applied in diverse industrial and engineering applications. However, their sound suppression potential is far away understood. The present study investigates P- and G-type TPMS sandwich panels’ sound insulation performances with two different boundary conditions through a method combining theoretical, numerical, and experimental studies. First, we use Reissner's theory for sandwich panels to construct the vibration governing equation for the four-sided simply supported TPMS sandwich panel. By introducing sound pressure as double Fourier series into the vibro-acoustic governing equation, we derive the theoretical solution for the sound transmission loss (STL) performance. Second, we employ the sound impedance tube method to experimentally investigate the STL performance of TPMS sandwich panels with free boundary conditions. Then, we numerically study the TPMS sandwich panels’ suppression of sound capacity under both boundary conditions based on the direct acoustic vibration coupling theory. The results obtained by the theoretical, numerical and experimental methods are in good agreement and demonstrate that the TPMS sandwich panels’ relatively good sound suppression ability. Last, we conduct parametric studies to correlate the TPMS sandwich panel design to STL performance. Results show that the G-type TPMS sandwich panel is significantly superior to the P-type TPMS sandwich panel in terms of sound insulation capacity, which can achieve sound insulation of more than 20 dB at a broad frequency range, extending from 250 to 5000 Hz by an ultrathin thickness of about 2.4 cm, approximately 1/57λ for the lowest working frequency. Besides, the P-type TPMS sandwich panel's sound insulation capacity is more sensitive to the chief design parameters than the G-type one. Moreover, the constant (C) and the latt