钢花管是管棚支护结构中的核心承力构件。将超声导波技术应用于钢花管的无损检测显得十分重要。首先优化选取了适用于钢花管检测的压电陶瓷片尺寸以及激励频率为 30kHz 的 L(0,2) 模态。为研究钢花管管体上的 孔对低频纵向超声导波检测能力的影响，试验研究了钢花管孔数与检测信号特征之间的变化关系。结果表明：钢花管孔数的增加对频率为 30kHz 的 L(0,2) 模态回波信号幅值几乎没有影响，表明低频纵向超声导波具有对长距离钢花管无损检测的潜力；而频率为 30kHz 的 L(0,2) 模态的群速度随钢花管管体中孔的增加呈线性下降的趋势。该 研究结果为基于低频超声导波技术的钢花管无损检测奠定了一定的基础。

A steel floral pipe is a key load-carrying member of pipe supporting structures. It is important to apply ultrasonic guided wave technique to nondestructive testing of steel floral pipes. Firstly, the dimensions of PZT elements are optimized for the inspection of steel floral pipes and the excitation frequency of L(0, 2) mode at 30 kHz. In order to investigate the effects of the holes in steel floral pipes on the inspection ability of this low frequency ultrasonic longitudinal guided wave mode, the relation between the number of holes and the characteristics of received inspection signals are obtained from experimental research. Research results indicate that the holes in a steel floral pipe have almost little effect on the peak-to-peak amplitudes of L(0, 2) mode at 30 kHz. As a result, it is shown that low frequency longitudinal guided waves have potentials to inspect long range steel floral pipes nondestructively. Furthermore, group velocity of L(0, 2) mode at 30 kHz tends to decrease linearly with the increase of the holes on steel floral pipes. These research results provide a basis for nondestructive inspection of steel floral pipes based on ultrasonic guided waves in low frequency range.