研究了二维三元周期结构的声禁带加宽现象产生的物理机理 .用有限元方法分别计算了嵌入 1,3和 5排铁柱和具有橡胶包层铁柱的周期复合结构的声能量传输谱和禁带形成过程 .通过比较二元和三元周期复合结构中的声场分布情况 ,认为三元样品宽声禁带的形成机理是Bragg反射和局域化共振共同作用的结果 ,前者在高频段的作用更为明显 ,而后者在低频段起主要作用 . The physical mechanism of the sound-forbidden band broadening phenomenon of two-dimensional ternary periodic structure was studied.The acoustic energy of the periodic composite structures embedded in 1, 3 and 5 rows of iron columns with rubber cladding iron column were calculated by finite element method Transmission spectrum and forbidden band formation process.By comparing the distribution of sound field in binary and ternary periodic composite structures, it is considered that the formation mechanism of ternary bandgap in ternary samples is the result of the combination of Bragg reflection and localization resonance, The role of the high frequency band is more obvious, while the latter plays a major role in the low frequency band.