基于半波偶极子理论的锚杆长度无损测量仪设计

摘要

针对声频应力波法应用于金属锚杆无损测量时反射波信号处理复杂及测量长度受限的问题，设计了一种基于天线理论的锚杆长度无损测量仪，通过添加一根金属参考线的方式，将单根金属锚杆等效为半波偶极子天线，采用AD9913作为天线馈源产生0～100MHz的正弦扫描信号耦合进金属锚杆，检测金属锚杆首次发生谐振时对应的正弦信号的频率，依据谐振频率与波长以及波长与天线长度的关系，计算出金属锚杆的长度。在整个测量过程中，电路对信号的相位特性不需要严格约束，对10m长以上的锚杆进行实际测量，绝对误差可控制在5％以内。%Aiming at the complex reflected wave processing and limited measuring length of audio frequency stress wave method applied in non-destructive measurement for metal bolt. A new non-destructive measurement method is developed based on half-wave dipole antenna theory, by adding a metal reference line, the single metal bolt is equivalent to half-wave dipole antenna; AD9913 is used as antenna feed to generate a 0~100MHz sinusoidal signal, which is coupled into the bo the first corresponding signal resonance frequency is detected, in accordance with the relationship between frequency and wavelength, and the wavelength and the antenna length, length of the metal bolt is calculated. In the whole measurement process, no strict constraints are required for signal phase characteristics, and the absolute error can be controlled within 5 % in actual measurement of bolt more than 10m.