中文摘要：

首先分析声波在管柱中的传播机制和特性，接箍等效为声透层，依据突变截面管和波导管声波传播相关理论，利用传递矩阵法分析声波在钻柱中的透射和反射。对理想钻杆中沿管轴方向的纵波传播模型进行分析，推导出纵波频率方程。利用色散曲线对钻杆中纵波传输的频域特性进行分析，并通过有限长管试件进行声传输试验。结果表明：钻杆和接箍的长度和截面积决定了钻柱的频带结构，并且这种频带结构的变化呈周期性和对称性；在钻柱信道中，通带和阻带交替出现，钻柱表现为一种梳状滤波器，且在一个频带周期内随着频率的增加，通带先变窄再变宽，阻带则先变宽再变窄；钻杆长度增加使通带变窄，接箍截面积减小使通带变宽，钻杆各节钻管的长度不一致会使通带变窄。

英文摘要：

Firstly, the transmission mechanics and characteristic of acoustic wave within pipe string were analyzed. Joints act as acoustically transparent layers. Based on the theories of abrupt changes in the cross-sectional area of a pipe and acoustic waveguide, transfer matrix method was used to analyze acoustic transmission and reflection within drill strings. Secondly, the frequency equation of longitudinal wave was developed based on the transmission model that longitudinal waves propagate along the periodic drill strings. The frequency-domain characteristics of longitudinal wave propagation along the periodic drill strings were analyzed by using dispersion curves. The experiment of acoustic signal transmission was done with finite length pipes. The results show that frequency band mainly depends on the length of the drill pipe and area of the joints. The distribution of frequency spectrum exhibits periodic and symmetrical property. The pass bands and stop bands present alternately in this acoustical channel of drill strings which act as comb-filter. With the increase of frequency, the pass bands become narrow first and widen afterwards, and the stop bands widen first and become narrow afterwards in one frequency band. The pass bands become narrow with the length of drill pipes increasing, and the pass bands widen with the area of the joints decreasing. And the difference of drill pipes length leads to narrow pass bands.