基于磁致伸缩位移传感器原理测量波导丝泊松比与线膨胀系数

Measurement of Poisson’s Ratio and Linear Expansion Coefficient of Waveguide Wire Based on the Principle of Magnetostrictive Displacement Sensor

波导丝是磁致伸缩位移传感器的核心元件,为快速测量波导丝泊松比与线膨胀系数,基于磁致伸缩位移传感器原理,提出了波导丝线膨胀系数与泊松比的测量方法。根据应力波传播特性以及应力波波速受温度影响的特性,构建了波导丝线膨胀系数、泊松比与波速的数学模型;利用传统的磁致伸缩位移传感器结构,测量了波导丝在25℃、50℃时的扭转波波速;设计了波导丝纵波激励结构,测量了波导丝中扭转波、纵波在传播距离相同时的传播时间;计算了波导丝线膨胀系数与泊松比。实验结果表明:实验中Fe-Ga波导丝的泊松比约为0.302,线膨胀系数约为18.70×10^-6/K。本文旨在深入探索波导丝弹性参数的新型快速测量方法,为传感器中波导丝的选型提供新思路。

According to the propagation characteristics of stress wave and the characteristics of stress wave velocity affected by temperature,a mathematical model for the relationship between linear expansion coefficient,Poisson’s ratio and wave velocity of waveguide wires is constructed.The torsional wave velocities of waveguide wires at 25℃and 50℃are measured by using the traditional magnetostrictive displacement sensor structure.The longitudinal wave excitation structure of waveguide wire is designed and the propagation time of torsional wave and longitudinal wave in waveguide wire at the same propagation distance is measured.The expansion coefficient and Poisson’s ratio of waveguide wire are calculated.The results show that the Poisson’s ratio of the Fe-Ga waveguide wire is about 0.302,and the linear expansion coefficient is about 18.70×10^-6/K.The purpose of this paper is to explore a new and fast method for measuring the elastic parameters of waveguide wires,and provide a new idea for the selection of waveguide wires in sensors.