Research On Vibration Attenuation And Sound Insulation And Core Design Of Periodic Lattice Sandwich Panels Based On The Band Theory

ABSTRACT:Periodic structures (PSs) have stop bands characteristics. That is, vibrations or fluctuations in these frequency ranges cannot propagate in the PSs, so that we can achieve the goal of structure’s vibration isolation and noise reduction. Periodic lattice sandwich panels are typical periodic structures with many good characteristics, such as lightweight, high strength and high energy absorption. It is a kind of good building material with multiple functions, important scientific value and practical significance.Three kinds of new type of periodic lattice sandwich panels, N-shaped, X-shaped and overlapped pyramid are designed in this paper, and by using the COMSOL software, the band structure of three traditional lattice sandwich panels and three new lattice sandwich panels are analyzed and calculated. For the two-dimensional periodic N-shaped lattice sandwich panel, we discuss the influence of geometric parameters and material parameters on its band structure, calculate its vibration transmission curve and analyze the characteristics of vibration isolation. For the three-dimensional periodic pyramid lattice sandwich panel, the influence of geometric parameters on its directional stop band is discussed, the sound transmission loss curve is calculated, and its sound insulation performance is analyzed. The results are as follows:1. For two-dimensional periodic sandwich panels, three kinds of traditional lattice sandwich panels display no wide completely stop bands, while three new kinds of lattice sandwich panels present good features in stop bands. Among them, the N-shaped periodic lattice sandwich panel exhibits the best.2. For three-dimensional periodic sandwich panels, no completely stop bands exist for all the six kinds of sandwich panels, but the directional stop bands in the thickness direction exist. Among them, the pyramid periodic lattice sandwich panel exhibits the best.3. Thickness of the panel and lattice constant in plane has a great influence on the location of the center frequency of stop bands, and the height, width and diameter of bars of the core body can effectively change the width of the stop bands.4. The vibration transmission curve of periodic N-shaped lattice sandwich panels and the sound transmission loss curve of periodic pyramid lattice sandwich panels show that, within a certain frequency range, vibration and acoustic wave present distinctive attenuation, and this range is coincide with the frequency range of stop bands in the band structure. This shows that utilization of stop band properties of periodic lattice sandwich panels can effectively restrain the vibration and acoustic wave propagation in structures, so as to realize the application of vibration isolation and sound insulation.