Periyannan Suresh, Balasubramaniam Krishnan
Centre for Non Destructive Evaluation and Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600 036, India.
Rev Sci Instrum. 2015 Nov;86(11):114903. doi: 10.1063/1.4935556.
A novel technique for simultaneously measuring the moduli of elastic isotropic material, as a function of temperature, using two ultrasonic guided wave modes that are co-generated using a single probe is presented here. This technique can be used for simultaneously measuring Young's modulus (E) and shear modulus (G) of different materials over a wide range of temperatures (35 °C-1200 °C). The specimens used in the experiments have special embodiments (for instance, a bend) at one end of the waveguide and an ultrasonic guided wave generator/detector (transducer) at the other end for obtaining reflected signals in a pulse-echo mode. The orientation of the transducer can be used for simultaneously generating/receiving the L(0,1) and/or T(0,1) using a single transducer in a waveguide on one end. The far end of the waveguides with the embodiment is kept inside a heating device such as a temperature-controlled furnace. The time of flight difference, as a function of uniform temperature distribution region (horizontal portion) of bend waveguides was measured and used to determine the material properties. Several materials were tested and the comparison between values reported in the literature and measured values were found to be in agreement, for both elastic moduli (E and G) measurements, as a function of temperature. This technique provides significant reduction in time and effort over conventional means of measurement of temperature dependence of elastic moduli.
本文提出了一种新颖的技术，该技术使用单个探头共同产生的两种超声导波模式，同时测量各向同性弹性材料的模量随温度的变化。该技术可用于在很宽的温度范围（35°C - 1200°C）内同时测量不同材料的杨氏模量（E）和剪切模量（G）。实验中使用的试样在波导的一端有特殊结构（例如弯曲），另一端有超声导波发生器/探测器（换能器），用于以脉冲回波模式获取反射信号。换能器的方向可用于在波导一端使用单个换能器同时产生/接收L(0,1)和/或T(0,1)。带有该结构的波导远端置于加热装置（如温控炉）内。测量了飞行时间差与弯曲波导均匀温度分布区域（水平部分）的函数关系，并用于确定材料特性。对几种材料进行了测试，发现对于弹性模量（E和G）随温度的测量，文献报道值与测量值之间的比较结果一致。与传统的测量弹性模量温度依赖性的方法相比，该技术显著减少了时间和工作量。
